Continuing saga update aluminum radiator install
 

Figured I'd start a new thread since this whole thing is actually a conglomeration of a few threads; aux fan install, tranny cooler install, running hot, radiator advice etc.
For those following along this is where I'm at. Last week I installed a new Dewitts aluminum rad to help with a running hot problem. This problem occured mainly on the hi-way, 70mph or better, a/c on and 90 degree outside temp or better. My temps would get up into the 240 range before I shut the car down. Thats it in a nutshell. The list of fixes I attempted is long and all inclusive. This was the last step only because I didnt want to part with 500 bux earlier and kept trying the cheaper fixes first. I finally had no choice but to go for the dough.
Anyway, took a 22 mile two way ride on the hi way tonite, outside temp maybe 80 deg give or take a few. Traffic was heavy so going 70 or better was difficult. My temps for the outgoing 11 miles at 65 mph were in the 190-195 range with no a/c. The return trip was with a/c going and the temps were in the 205-210 range at 65 mph. I would have to assume that at 70 with a higher ambient temp my engine temps would be even higher. Oil temp reached 273 deg! Shutting off the a/c brought about a very quick drop in temps. At 50-55 the temp would read 175-178 so I assume that corresponds with the opening of my t-stat which is a hi flow summit bought 180 deg model. These readings are with digital nordskog gauges. Looks like I spent 500 for nuthin, wonder if mr dewitt has a money back guarantee? Probably not. If the summer has another day or two of 90 deg days and if I'm able to take the vette out I'lll certainly do so to confirm what I feel is the inevitable. This whole thing is extremely frustrating. I've worked very hard for the last 2 yrs to get this project road worthy and enjoy it and I always have to keep an eye on the temp gauge.
I'm gonna add my list of fixes just to avoid the "did u try this" questions.
new motor GM 290 hp crate
new water pump oem style
new alum rad
new fan clutch HD
new 7 bladed fan
all new belts, tightened
new chin spoiler
new chin spoiler extension
new rad seals
new hood insulation
a/c converted to 134
double pass heat sink tranny cooler
ran 100% water with water wetter
replaced old edelbrock alum performer manifold with new one in case the old one had a leak or was porous.
All new hoses including spring in lower one
hi flow t-stat
heater core by passed
mobil one oil
infra red laser temp gun
Lars rebuilt Q-jet
Lars rebuilt distributor
timed anywhere from 6 deg btdc to 16 btdc
2 1/2 inch duals, no cat
2 flex a lite 10 inch elec fans mounted inside the shroud
ran w/o the t-stat

Have I missed anything?
If I did please let me know I'll try anything!
Last thing I'm gonna try is adjusting the fan clutch according to a prior post.
ANybody wanna make me an offer for a 79??? Only if you live in a cooler climate, south of the mason dixon line need not apply!

Extremely frustrated in NY
ESU :willy:

Did you try a 160 tstat yet? is the clutch fan working .

Neg on the 160, cant maintain 180 wont do 160 for sure. Clutch is brand new.
ESU

ESU I'm sorry to see you so frustrated. :( I wish I had some suggestions for you. Have you tried fabing a scoop like rihwoods did on his '78? I don't have a/c on mine yet, and with I think the original radiator. I have only experianced the temps getting up to 210* at 70mph 3000 RPM 4spd trans air temp 97*. I hope dealing with this is less stressful than being on the force.

:eek:

Dumb question? Why...when they designed the radiator to lay at roughly 30 degrees, did they not design the radiator for these cars with the cooling fins angled at the same degree for "straight through" air flow? Uninpeded from the front to the rear of the fins? Does this make sense? I truly believe the flow of air is disturbed as it passed through the fins...:leaving:

100% could be a big part of your problem. Antifreeze actually helps keep it a bit cooler, and I would also double check the themostat is actually opening correctly. Easy to do, put it in pot of water with a thermometer and see when it opens. I would go with a 160 since you are having problems. It should open at 160 so the engine should run cooler as well. You put on a new radiator, but how about the flow through the ac coil in front of the radiator? Is it blocked? That will keep the radiator from cooling. Also check your fan clutch. Little things add up. The initial air flow is not the best and these things run hot anyway. Good luck.

Keep in mind that although the 'Vettes run a little hotter than some other vehicles, the engineers did a good job considering the space constraints. I think the solution lies in something that has deteriorated or has been changed from stock.

You said that shutting off the AC made the temps drop noticeably. Maybe the problem is in the AC system. R134 is not as good a coolant as R12 so maybe the condenser is running a lot hotter as a result of the conversion and heating up the air going through the radiator. Also, why aren't you running a 50/50 mix of anti-freeze in the system? The anti-freeze will raise the boiling point of the coolant as well as lowering the freezing temp.

:cheers:

Rick B.

ESU,
From what you reported above, that doesn't sound all that bad. You said it would go to 240 before and you would shut it down.
Now, with the new radiator it went to about 190 without the AC and 210 with the AC, and considering that you are using 80-90 degree air for the cooling media, that's not far from normal. Should you be running cooler, yeah probably, but you certainly aren't going to hurt the engine at those numbers. The oil temps (275) sounds a little fishy though, why is that so high?
I'm not crazy about running electric fans and mechanical fans at the same time. In fact, just this week I had a customer that sucked the electric fan blades back with the mechanical fan and it blew the fan blades right off. I would like to see one or the other on there to see if it makes a difference with the new aluminum radiator. What's the total CFM of the flex-a-lites? Maybe they are pushers? Just offering ideas...
Now I can't take back a used radiator but if you want to try the Spal duals (2780 cfm) and eliminate the shroud and the mechical fan I will let you return these if you are happy with them. I don't think I've ever had anyone tell me an aluminum radiator/dual spals didn't work. If the flexalites are 2000 cfm or more, try removing the mechical fan completely. Maybe it's blocking the electric fans flow. If they are below 1500 cfm, try removing them and see what the mechical fan can do. If you want to talk more, call me at the office tomorrow (Friday). My secretary is on vaction and I get to answer the phones all day! 810-220-0181

ESU...Don't give up...except for engine and that alumimum rad,we have the same set-up...let's see what happens when you re-calibrate the clutch fan...
PM coming....

I only tried 100% water for a few weeks because I was told that water actually releases heat better and that the water wetter works best with 100%water. I have since returned to a 60/40 mixture of water/af to take advantage of the higher boiling point. On more than one occasion I've used a garden hose to try and blow thru the condensor for leaves and crap. This last t-stat is actaully my 3rd one, they cant all have been bad.
ESU

The a/c 134 vs r12 thing is possible but now what? Replace my condensor for another $125 plus the cost of an evacuation and refill. Oh and another $60 or so for a new drier? Not sure how much more money I want to pour into this. ANti freeze is now 60/40 approx, 100 % water was only a short experiment.
ESU

No, it doesn't. :nono: Nothing will run cooler than straight water however water alone offers no inhibitor package and that will void our warranty. I don't think ESU is running straight water anymore, he just tried it for trouble shooting, Right ESU? You do need to have some coolant in there, at least 30%.

It seems the "angle" of the radiator always becomes a question in radiator/cooling threads and that will not affect anything. When things are working right these systems work. My 80 still has the stock ten year old copper unit and I can do just about anything on any day. It can be 100 out, with the AC on, in traffic, and the temp goes to 190. One of the reason is that it is simply un-modified, bone stock and everything is working as it should. Block the bottom of a sieve and see if the water flows out still:lol:

Ahh, the old raise the boiling point idea. I here this one everyday too. Yes, a mixture of 50/50 will have a higher boiling point and changing to a higher psi cap will increase it too however, unless you are going to see 270 or higher, who cares if you raised it? If the system is running at 190-220 range it doesn't matter if you raised the boiling point from 240 to 270 does it?

WHen rihwoods starts mass production I'll be 1st customer. SOmetimes this is more stressful that the force .
ESU

Can you explain what you mean by re-calibrating the fan clutch?

Example: The one I have is calibrated to start engaging at 170/180...it will fully engage at 220...it is a thermal clutch fan with the coiled spring that senses air thru rad...that spring can be reset so clutch fan comes on sooner...or so we have learned...mine is new...and works...but I don't like the idea of it fully engaging at 220...think it free wheels at about 2800 rpm...
Rich

Tom,
Thx for the reply and please before someone hijacks this thread or misinterprets my comments i am NOT in anyway trashing your product! Does everyone hear that? Now that thats out of the way. If I stayed at 210 at 70 mph, a/c on, 90 plus day I'd be very happy. 215 even might be OK, higher than that doesnt give me a lot of leeway if something else goes wrong.
As for the fans, I was running all 3 with the c/b rad but with the alum I'm only running the mechanical for starters. I wanted to see what the reaction was. I left all the electrical hook ups in place so I can re-install with a little less headache. . I had one hooked to the a/c with a relay and the other to a temp probe in the rad fins with a controller set to about 200 deg.
The fans are 10 inch pullers, they sucked as pushers. They flow either 1050 or 1250 cfm each I forget. So a little over 2000 cfm minimum.
As for the oil temp I agree thats hi, I was told 230 -250 is normal. This is a fresh oil change less than 100 miles, mobil one. This temp also came down quickly after turning off the a/c.
As for the SPALS I'm not sure about another couple hundred bux right now, my pockets are bleeding. I will however call you tomorrow just to talk, thx for the offer.
ESU

I just hope you get the problem solved, and have a car you can enjoy. In the mean time I will keep watching as the saga unfolds. Just think cooler weather is a few months away, and you won't need the A/C. I think you should check the oil temp with a analoge gauge if you haven't done so already. That temp seems high, but I could be totally wrong.

I can actually hear my fan spinning up to about 2800 then it winds out and I no longer hear it. Does this mean its now freewheeling? Funny how my problem crops up at 3000 rpms just when I can no longer hear mine spinning,
ESU

Of course me being related to Mr Murphy and his law my heater core has a slight leak/drip to it so during the cooler weather when I open the bypass valves I have to keep refilling every now and then.
ESU

gonna grab a beer and head to bed, maybe the wife will have sympathy on me lol.

Yep..they dis-engage about that RPM...assumption is 3000 rpm/higher,you should be getting enough air flow at 65-70 + mph or so thru grille/valance openings...that's why I slow down if temps get high..to let the turkey kick in..

Rich

This topic has been on my mind since I've been dealaing with my own cooling problems which I think I've solved. My problem now is I think I've overcooled when on the highway and have been trying to find a way to cool a little better in heavy stop and go traffic with the ac on. I'll throw out a few thoughts which may or may be helpful to you.

You mentioned a Summit high flow thermostat...I looked it up on their site and I wonder if it flows as well as a Robershaw / Mr Gasket. Instlallinig the Mr Gasket brand of high flow stat DRAMATICALLY reduced my temperatures. It may be worth a try. Secondly, there are some different brands of fan clutches...is yours really a heavy duty? I've been spending some time on the Hayden web site trying to find a way to get a heavy duty fan clutch on my 71 to improve low speed cooling. According to their site the HD clutch turns at a faster speed than their standard thermal clutch. Its easy for any company to throw the word "heavy duty" on their box, but is it really a quality brand. http://www.haydenauto.com/index.htm

Hope this info is helpful.

This is not meant to hijack your thread.I have a 74r with the largest custom rad that can fit in the space,no shrouds,no seals no mech fan.it has an oil cooler rad and a trans cooler rad stacked in front of it at the bottom,has the standard stock chin spoiler only.My 383 and custom long tube headers make fierce underhood temps,i have a single electric fan puller 14" rated at 3400 cfm....i have no engine temp issues at all even when autocrossing,none in stop/start traffic even on 100* days....i have a standard 180 thermo with manual override switch....i do not have aircon....but as tom said earlier there is no obvious reason for you to have these problems......sorry i don't have an immediate answer,but there must be one....john:thumbs:

Put a 160 tstat,or try without one and see if any change.

I called Hayden after a fun two days running my 78 L-82 in Amboy,Ca in temps of 110-112 F last July....The tech guy said the fan clutch calibration was 170-220 F...(my old GM thermal clutch fan engaged sooner than 220..I'm certain of that and it was noisy)...my stock thermostat is supposed to be 195 F...think I'm going to pull the 180 and go back to the 195 just for giggles/tee hees...and see what happens...another discussion I had with Hayden is my 7 blade fan pitch...he told me I cannot go to their "Severe Duty" clutch unless pitch was over 2 1/4"...my rough measure is my pitch is 2 1/8" -2 1/4",so I'm sticking with either HD or Standard..
BTW...I tried running A/C (70 mph)pulling a gradual grade(Amboy to Barstow) and temps creeped...slowly..to 220)...I got chicken and shut A/C down...temps came back down to 205 and pretty much stayed there...and Raytek ground temps were 150 F...:ack:
Rich

2 things to check: timing and vac leaks. 6-16 degrees is not enough advance. Retarding spark will cause it to run hotter. I tried running without a vac advance distributor, and it would heat up over 220 on the highway. Around town it was fine. You need 36 mechanical advance in before 3000 rpm, then another 10-16 on a vac cannister at cruising speed for 52 total at cruise.

I learned this from forum member Matt Gruber who dyno tunes down here in FL.

Vacuum leaks will make it run lean and hot too.

I'm probably thick headed,but I can't understand the 160 stat idea...
and here is why...my 69 502 has a C/B four row, clutch fan (5 blade) and a 180 F stat(no A/C)...since June,where I live air temps have been 90-100...a few days at 113 (new record)..this 69 runs no hotter than 205 in stop/go traffic,on highway at 80 mph even pulling a hill...in 90 F just tooling around town at 40-50,it runs 180-195...not a problem IMO..

Rich

thermostat
 

Take the thermostat out of the equation. Do the boil water to see when it opens. I worked with an old time mechanic who showed me 4 different brand new thermostats that opened at different temps than they were supposed to. Some did not open enough to allow decent flow. So this is important as several other people have stated.:)

I've boiled some...but now I check thermostat with my Raytek mini temp gun as engine warms up...just by reading stat housing....also use those readings to compare my temp gauge readings....:)

And Raytek Me2 temps were running about 6 degrees higher than everyone else...

:rofl: Think your tee shirt reading was 102 F.....:lol:

so do you have the dual electric fans installed but not hooked up and operating? I guess they spin on their own when you are at highway speeds, or maybe even the mechanical fan gets enough air going to make them spin. But are they obstructing air flow? If you are overheating at highway speeds I would suspect an airflow problem. How hard would it be to remove the electric fans that you aren't using?

What kind of aluminum H2O pump are you running? The 1984 and later pumps are reverse rotation for serpentine drive belt systems. Maybe your H2O pump is causing problems, I would also say that timing that is not advanced enough will cause overheating problems along with lean fuel mixtures. Have you had Air Fuel Ratio checked? is your timing at least 8 to 10 degrees initial with a decent advance curve? did you get the cooling system filled all the way? (I fill my Vette through the thermostat housing, then mount the Tstat and finish filling the radiator.) One last thought, is the radiator sealed to the support like it was when Chevy built your Vette? If the radiator insn't sealed, air will leak around the radiator and kill the cooling efficency of a Vette.

Other than installing dual spalls there should be nothing wrong with your cooling system. I continue to believe it has something to do with your engine. Your timing,as suggested above, could very well be causing all the problem. You didn't say if you had the problem before the engine swap. There are too many people not having your problem with the changes you have made. You will solve it and all will be good!:thumbs:
Bernie

Mine was hitting about 210 on the highway with the AC on, 195 everywhere else. That was with a C/B rad. with dual spals, the cultch fan wouldn't even keep it from overheating at idle, much less going down the road.

Went with an alum rad. and dual spals before i put the motor back in this time, and I cant get it to go up to 190. Idles around 155, normal driving 165, and AC on about 180. I left my thermostat out but now I'm thinking I need to put it back in. after 5-10 minutes after shutting it off I can lay my hand on the radiator and it's cool, try that with a C/B.

I'm not saying dual spals will correct your problem, but it can't hurt. My motor is radical and put's out a tremendous amout of heat under the hood (hot enough to melt cheap plastic wire seperators!!), so the inside of the motor has to be way hotter. BTW, I live in Ga. and the temps here are high 90's to 100's all summer.

The 160* thermostat will only set his minimum coolant temperature (and he's way past that). It won't have any effect on the coolant maximum temperature.
I agree that temporarily removing the thermostat (for testing only) might provide some interesting information regarding the effects of coolant flow rates and cooling differences. But I'm guessing the solution will be unrelated to the thermostat.

Let me preface this by saying I drove a 1979 for 17 years.

I will go against the current by saying your 1979 is probably running at perfectly normal temps. I base that on those years of experience at summer temps from 40F to 100F. A t-stat of 195F is correct for your car (for emissions reasons). In fact if you go to a GM dealer that is the only one they stock. That sets the baseline, warm-up temp. At the ambient temps you mention it is probably open 80% of the time. Switching to 160 or 180 will make no difference. Water boils at 212F. If you use a 60/40 or 50/50 coolant mix and combine that with a 15psi rad cap, that raises the boiling point quite substantially. Your temp gauge is red-lined (danger zone) at 250 if I remember correctly. I would also point out that the optional GM auxiliary electrical cooling fan in 1979 had a temp sensor/switch in the passenger side head that activated at 238F.

All this to say that operating temps of 195 to 215 are not unusual. In fact at the latter, water under 15psi of pressure would not even boil. My 1979 did not have A/C but at 70mph on a 90F day the top of the range at 210-215 was consistent over many summers. I sold the car in 2003 (to family) and to this day it is still seeing those temps. And still running well.

http://img.photobucket.com/albums/v1...tricfan003.jpg

:iagree: Check your owners manuals these emission cars are setup for 210-230-they get better milage and pollute less at those temps..

I believe he has a new GM 290 hp crate engine. Not sure how much of the stock emissions crap has been hooked up to the new engine.

My clutch is either a 4 seasons or hayden, cant remember which I ordered. It was described as a HD, thermostatic type. I can try a robert shaw t-stat, whats another 15 bux.
ESU

Isos,
my car was tnued by Lars last year, carb and dist, timimg is as u say, 16 total, 36 in by 3000, 52 at cruise.
ESU

I can watch my temp gauge and see when the stat opens. It usually maintains 175-178, then for a few seconds it will go to 180+ then right after it will go back to 175 or so. Seems to me to be indicative of the motor gettng a little hot, the t-stat opens and cools it down soon after.
ESU

As for vac leaks, this has always been a concern of mine. Even with a brand new motor I only pull 12-13 on the gauge. I've isolated all vac connections on the motor and still only 12-13. It's one of the reasons I changed the manifold, thinking I may be leaning out and causing a hot condition. Every hose has been changed along with the headlight actuators etc. Manifold even after being changed was removed and replaced by me once and once I brought it to a shop just to be sure, still 12-13. I pulled the plugs and they dont show a lean condition.
ESU

I have a chrome t-stat housing so I cant read off that.
ESU

The dual elec fans were previously hooked up with the copper brass rad but are not hooked up now or even installed. I'm running just the mech fan just to see what happens. I left all the electrical hook ups installed for ease of re-installation in case its needed.
ESU

Dont have an alum h2o pump, its a factory style pump purchased from pep boys when I installed the new motor 18 months ago.Timing right now is 16 initial with a LArs rebuilt and tuned dist. I reburped the system when I put in the alum rad by parking the car on my very inclined driveway and inserting a 2 liter soda bottle into the rad opening and half filling that with water/af to watch it burp.
All new seals from doc rebuild are in the car.
ESU

The old motor ran just as hot with a 3 row rad. When I swapped motors and it still ran hot I bought a cheapo copper brass 4 row rad and put that in. Unfortunately it was late sept of last year and the hi ambient temps were gone, the motor ran at 180 all day long and I thought I licked my problem. This summer when the 90 plus days came back so did my problem. The only part left over from the old motor was my intake manifold, also one of the reasons I changed it , the carb and the dist (MSD). Carb was rebuilt by Lars. For a awhile I even ran a a new edelbrock 1406 carb just to see what happened and still no good.
ESU

The smog crap is all gone, no cat either.
ESU

How's the radiator cap? Do you know that it's holding pressure as it should?

Cap is new 15 or 16 lb, not sure.

wow man it looks like you have covered just about everything! I have nothing to offer you.

I just wanted to chime in and try to dispell the myth that a thermostat won't change the overall operating temp of the engine. It will.

I used a 170 stat with a new alum radiator. Never ever got over 170*-175* (in car guage) even in 100* heat. Ever.

I swapped to a 195 and now it is right under the 200 mark and never budges above that. Of course this is a 1975 l-48 and doesn't produce much power/heat. But the thermostat DID change my operating temp.

You are missing the point, if your car runs at 210, changing from a 190 to 160 stat will do nothing. In your case of course your temp went up when you change the stat since it was operating at a temp lower than the 195 you switched to.

I realise that you don't want to spend any more dough, but if the oil temperature is your worry, why not install an oil cooler.

I am considering fitting one to my '76. I have a new 383 with no smog stuff, so the carbon canister in the left hand of engine bay has been removed. I am lookking at installing a small cooler in here where air exiting the engine bay via the fender side vent will pass through the cooler first.
This should knock a few degrees off my oil temp, without adding more obstructions to the front of the radiator, or adding heat to the engine bay.

Sounds like you've tried everything else, I admit, my first thought was something wrong with the engine to create too much heat in the first place, but you seem to have addressed all the usual suspects there.

Also sounds like the a/c being on makes a big difference. This can really only be due to the heat from the condenser pre-heating the incoming air and reducing its cooling efficiency once it gets to the radiator. No simple or cheap solutions, but perhaps spacing the condenser further off the radiator would allow more 'fresh' air to access through to the rad.

Best of luck,
Douglas
From normally chilly Scotland, but basking in the high 80's this summer. Hmmmm, global warming, I know its a bad thing, but......:)

In my opinion, running at 185*-200* is fairly typical. Add a few degrees when A/C is turned on and a few degrees for days when it's above 90* outside. Running 210* on a hot day with the air conditioner on should not be an issue. On a recent cruise driving 70-80 mph with temperatures in the mid 80's and no A/C, my temperture got to a bout 195*. Both C5's I was traveling with were running over 220* without their A/C turned. No one was concerned that their car was over heating or running too hot. From my understanding, a C5 is expected to run over 200 degrees.

Oohhhhhhhh I see...ok. :thumbs:

Would it be possible for you to post some pics of your setup. Maybe someone here will be able to spot something we've missed. Is the seal that fits between the top of the radiator and the hood in place?

over heating?
 

All though you installed new exhaust I would recheck heat riser or restriction in the exhaust system. I hope yoy can fix it . Good luck Ron.

One difference here: Clutch fan...the older GM thermal clutch fans fully engaged at 190 F....and interesting is they disengaged at around 3500 RPM....
Hayden current clutch fans fully engage at 220 F...and disengage at around 2800 RPM...
Think about what difference that makes...that to me means a "shift" to higher operating temps...
By the way..this info is noted on Dewitts coolingpdf article on his site...and it got my attention..;)
Rich

Do not lower your thermostat temp, a thermostat needs to close for the cooling system to maintain a constant temperature. This allows the coolant in the radiator to cool. Your’s is probably staying open all the time. If anything go to a 190.
Put in a 50/50 mix with Water Wetter.
Take the radiator cap off and allow it to reach operating temp to release trapped air.
Put your timing as close to factory spec as possible, make sure it’s not advanced.

I have a Dewitt’s radiator and recently started my hi-performance 350 up after a rebuild. With the engine sitting there being revved it never got above 200. I live in Virginia where it’s hot as he**, the car didn’t run hot before the rebuild. I have a 180 thermostat with a small hole drilled in it to release trapped air. It’s not the climate, the car has a problem. Good luck.

Cory you said you have 12-13 inches vacumn-do you think at 70mph you could be lower yet and not pulling all of your 52* advance in?Also 2979 has a point if you still have a heat riser-those were vacumn controled.

:iagree:

Heat riser/EGR has been removed but the valve is still in the pass side exhaust. Cant figure out which way its supposed to for open, up or down.
ESU

I'll take some pics, top seal is in.

Do you have it secured so it wont move?

I can idle all day long with a/c on and never go above 180 in the driveway, same if just 20-30 mph around town. Hiway above 70 w/ a/c is when I get hammered.
I burped the rad for 30 mins after the rad was installed. Not going with a lower stat for sure, not going to help.
Water wetter works best with 100% water, very little help on a 50/50 mix. ALready tried it anyway, no help.
ESU
ESU

Not sure but Lars did do my timing last year and it was ti his all around specs. That heat riser valve for the EGR on the pass side exhaaust is that what u mean? It's still in, but unsure which way is open or closed, it goes either up or down. Anybody got one laying on their work bench to check?
ESU

Nope, I push it up or down depending on my mood lol. Wish I knew for sure which way then I'd wire it that way.
ESU

EGR: intake; removed, noted
Heat riser: exhaust, assume still intalled -
when the weight on the heat riser is raised up (horizontal) the valve should be closed; when in the lower position (vertical) it should be open. You can use some machinist wire, coat hanger wire, etc., to hold it open for a test. Sometimes on old cars, the valve blade will rust off of the shaft and fall into the exhaust pipe where you can't see it, potentially plugging or partially plugging the pass. side.

It needs to go down to be open-----------vacumn held it closed before

So if I push it down it should be open?

down it shall be.
ESU

If your A/C system is working properly, it's either your:

1) Radiator and/or shroud seals

2) Timing is advanced.

Wouldn't run 100% water in a street car, there is no advantage. It may give you a slightly lower temperature on a race track. 50/50 with Water Wetter and forget it. Good luck.

I agree. With the weight down it is open. It is vacuum-actuated via the EFE (early fuel evaporative) valve located on the snout of the t-stat housing. That is designed to open the valve when engine coolant is about 120F. You seem to have removed that system so the heat riser may be mis-behaving and looking for guidance that is no longer there. Or it may be corroded shut, directing exhaust through the intake manifold cross-over passage and thus making things very hot under the carb and by extension nearby coolant. Either weld that valve open or gut its internal butterfly valve. Mine is mig-welded open.

In this pic from last October (32F) at start-up temps you can see the free flow of exhaust on both sides at a time when the heat riser should be closed on the passenger side.

http://img.photobucket.com/albums/v1...storage006.jpg

It's just the opposite. The engine, and that's the expensive part we care about, only cools when the thermostat is OPEN, not closed. Cooling the engine requires that the heat (via the coolant) flow out of the engine into the radiator. Yes, the radiator will cool down if the thermostat closes, but at the expense of the engine heating up further. Not a good thing if engine overheating is the problem.

The thermostat should never let the coolant temperature get hot enough to damage the engine, if it does it’s broke. If you remove the thermostat the water in the radiator will not have as much time to be cooled down. A system with a thermostat will maintain a constant temperature better than a system without a thermostat, that temperature should be in the optimum operating range of the engine. A car without a thermostat will be more subject to outside temperature variations and different driving conditions.

:iagree:

What's the problem? I don't see one? I wish I could run 210* @ 65 mph with the A/C on. My 2003 Chevy truck runs 210* everyday, all day, and will occasionally get to 225* in heavy non-moving traffic.

Reading your above info., I think the Dewitts radiator fixed your problem. Folks get real anal about temps, but motors run better, and actually prefer the 200-220* range. I tried running mine with a 160* stat, and though it worked good on the highway, in the city it sucked as my temps were sometimes as low a 160*, and the motor didn't like that at all.

I say go drive, and have fun!

One more time, have you ran with out the t-stat and see what happens,it wont cost money to pull it,and if it runs cooler install a cooler t-stat.or maybe I didn't pay attention of what the problem is.

[QUOTE=ESU]I can idle all day long with a/c on and never go above 180 in the driveway, same if just 20-30 mph around town. Hiway above 70 w/ a/c is when I get hammered.
I burped the rad for 30 mins after the rad was installed. Not going with a lower stat for sure, not going to help.
Water wetter works best with 100% water, very little help on a 50/50 mix. ALready tried it anyway, no help.
ESU
ESU[/QUOTE
You said you put a chin spoiler on,it helped my car run cooler,
do you think maybe the clutch fan some how stops working at hiway speeds

As I suggested earlier, your car is normal. Just get out and drive and enjoy!

Read through the whole thread but I'm not sure if you said whether or not you checked your air/fuel ratio.

One thing I would try just for a short term thing is to richen up the mixture a bit and see how it runs, just to see. If it does nothing then that obviously rules out being too lean.

MS.,
compared to your problems this probably seems minor. My new trailblazer also runs 210 all day but I believe thats the way they were engineered. When the vette gets higher than 215 I start to get nervous. Just dropped the timing to 6 btdc and still made 220 after some hi way and street driving with a/c on. Without a/c I do OK, wonder if something in that system is screwed up? After a long conversation with Tom Dewitt we both think its not the cooling system its the motor generating too much heat for whatever reason. 3000 rpms is the magic number, maybe my MSD box is whacko who knows?
ESU

T-stat was out, ran hotter, faster.
ESU

Never checked A/F, dont have a gauge and wouldnt know how.
ESU

:crazy:

Huh? That makes no sense... At worst, it should have made no difference (which is what I would expect after having read through this thread). At best, it would have run cooler.

Very strange...

Tom...I'm really glad to see you engaging threads again relevevant to your expertise! Thanks for not "giving up on us":thumbs: and :cheers:

How many miles are on the new motor?
The car runs well around town ,but only gets hot 230+ with ac on and going down hiway but is normal when ac off 190.
Sounds like you need more cfm throught rad.

You say you're running a q-jet right? Try a size or two skinnier on your metering rods and see what happens.

Cory-the heat riser not in the open position can be a source for the motor generating too much heat-did you wire it open and try it?

*Edit*-Offending comment deleted.

Be patient Paul-give him a little time to get used to that 215 figure.I think he was used to it not stopping around there and he is a little gun shy "and" he does have new motor.It sounds to me like there is a good possibility with the new rad. it can maintain that even on a hot day.Lets keep our fingers crossed for a 90* day roadtest.

OK, it's just a shame to see so much time and $s spent for a non-issue.

*Edit* - Taking back a few words. The threads have been long and my memory is short. My conclusion is that the DeWitt rad solved the problem. I do not have or endorse that product from experience but they have a fine reputation. I do have an original Harrison aluminum rad in my 1967 and it runs 180* in the city and about 205* in highway heat at 70mph. No A/C.

Not completely off topic but still sorta on topic.

When I switched out my original 3 row copper for a northern aluminum semi-direct fit in my '81 the temps went down from 200 degrees in town and 220+ on the highway down to ~180 everywhere. I've driven it up to LA from San Diego a few times since the install and autocrossed with it. Barely reached 200 during autocross. This is with an automatic with A/C that doesn't work right now. The condensor is there but it does nothing right now.

I would think his temps would be a bit lower than 200 degrees with an aluminum radiator and a new engine. My engine was rebuilt about a year and a half ago so it's relatively new and has no issues.

Less than 2000 miles on motor.
ESU

Wired open, will take a ride tomorrow.
ESU

Paul, are you honestly gonna tell me that you wouldnt fret if the temps in that gorgeous 67 (?) of yours hit 240 and looked like it might go more???? If not then you've got brass b____s and deep pockets . I dont have either. As DW said I'm still waiting for a 90 plus day so I can take a good ride on the hiway with no traffic so I can maintain 70mph and we'll see what happens. So far I've seen maybe a 5 deg drop in temps at this point. Not enough to draw the conclusion that all is well. If you think I like spending all this money for nada you're crazy. Especially with a nickname of ole t-rex arms if you know what I mean lol. I've asked for opinions for the last year on this forum as members here have been an absolute godsend when it comes to helping me get this car on the road. I've tried suggestions in a logical and thought out progression to attempt to solve my problem. I didnt just thro money at this thing. Like I said 240 deg aint nothin to sneeze at and I certainly wouldnt call it a non issue. 210 215 I could live with, we'll see what happens on the road.
ESU

Esu
 

hey LT. ,Ive been reading about your problem and im having the same with my 75 l48. spent 11,000 on it to get street worthy and afraid to drive it more than a half hour without creeping into 210-230 range. broke my original shroud when redoing engine and installed electric fans and a good friend old school mechanic said to me that chevy's engeneer is smarter than us and to put it back the way it was.so today i put the mechanical fan on without shroud for the hell of it and it didnt go over 210 (ac not hooked up yet).some mods to engine but orig rad and 160 tstat. by the way im right over the bridge from you and also on the job UCSO #7 NJ. ill be watching and learning.. and being im close if i can help,let me know..

That shroud is very important as are the seals that go with it, dont leave those out. It may cure your problem but it didnt cure mine, be safe,
ESU

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