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

 

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.

 

 

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...

 

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.



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. 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

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