ESU

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

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

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

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

ESU

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

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

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

ESU

The smog crap is all gone, no cat either.
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gerry72

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

ESU

Cap is new 15 or 16 lb, not sure.

flood

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.

Fevre

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.

Blue Juice

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......

mandm1200

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.

flood

Oohhhhhhhh I see...ok.

jdmick

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?

rjones2979

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.

rihwoods

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

Ed Blue 03

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.