Still battling the overheating issue on my car.

Back information: 76 cutlass 442, originally had 350 engine.
3.42 rear end, auto

Put in a built 455, nothing monster but better than stock.

Still using original 3 core radiator. Put in a 195 thermastat, runs 210.

I have since decided the old radiator isn't cutting it and have since ordered a new AL radiator out of Summit SUM-380457.

I got home from a 40 mile cruise last night popped the hood, and tried turning the radiator fan, it turned with a tad bit of resistance. Shouldn't the fan be locked since the thermo clutch is hot? And release and turn freely when cool by running down the road or after sitting over night and lock in when hot?

https://www.opgi.com/cutlass/1976/co...ing/fans/FC57/

This is the type of fan clutch I put on new a few years ago when I finished up the engine build...

 

No, the fan will not lock solidly, it will just get more difficult to turn. The fan clutch provides a viscous coupling between the water pump shaft and the fan, kind of like a torque converter on an automatic transmission. If yours doesn't have significant resistance when hot, it may be faulty.

Also, after sitting overnight the fan will be hard to turn because the silicone fluid has drained from the reservoir into the working area.

http://www.haydenauto.com/upload/Hay...n-clutches.pdf
A thermal fan clutch is engaged on a cold startup because the fluid drains into the
working area when the engine is shut off. The fan clutch will slow down shortly after
startup as a result of a pumping action produced by a difference
in speed between the shaft and the body of the clutch.

 

210 is not overheating with a 195 thermostat.

 

I agree, but I would modify that to say that with a conservative 10% +/- margin of error for a mass market non-scientific thermometer, at about 190° your actual temperature could be anywhere from 175° to 215°.

- Eric

 

Which is still not an issue with that thermostat.

 

My point exactly: It could not be a "problem" at all. The thermostat could be opening and closing at exactly the right temperature, but the gauge is not a calibrated scientific instrument.

Your observations are only as accurate as your equipment is.

- Eric

 

Very true. Not to say this applies to the op, but sometimes people install gauges in their car and realize in traffic that temps start to climb. The temps can reach 215-220 and then drop as the car starts to move back up to speed. This is normal.

 

Pay attention to the T-Stat too...Be aware they are not all created equal. Steer clear of offshore junk. There is standard and heavy duty T-Stats as well as specialty aftermarket stats. I use the Stant HD equivalent of the standard recommended PN for Olds. It touts better regulation ... less hysteresis...or less dips & spikes for better control. The Robertshaw design is supposed to be good. Bottom line is it doesnt sound like you have a problem.

 

Thank you for the input guys ! I wondered what the +/- would be over the rating n the thermostat.
I am concerned though that the factory three core behind the original 350 smogger won't cut it for a heated up 455 in midwestern summers with the a/c blowing.

Have a Summit AL replacement radiator, crossflow with 1" tubes arriving today to install.
For the midwest guys Iowa, Nebraska, Kansas, Illinois, etc.. what temp of T-stat have you guys used with a/c cars, out of curiosity.

 

Just to be clear, I don't know the exact tolerance of a standard automotive temperature gauge or thermostat, but 10% does not not sound out of line for a standard consumer product. If you went to 5%, you'd still have 10° leeway either way.

- Eric

 

Well guys, i worked late after work on my car. Installed the new aluminum radiator from Summit Racing, Put in a 180 degree thermostat, and new premixed coolant we sell at our Deere Dealership, and she is running like a champ. Temps lower and holding with the larger radiator.
next on tap, recharging the a/c and finding where it leaked over the winter.

 

Excellent!

- Eric

 

Update, cooling issue controlled. Transmission is still leaking. Not from the pan...
just some back history, had the transmission rebuilt in 2011. Put in the car and sat until car went to the body shop in 2/2014. Car back in 12/2015. Snafu happened on transmission, original shop pulled and rebuilt.
However the front pump seal, not shaft seal, is leaking after driving the car... I am greatly regretting not having just bought a rebuilt and tested transmission.

I may have an intake leak now to on the back of the intake, going to look around on the brake booster hose first before anything drastic... But will wait until the trans shop will pull the trans again, and see what is up with that pump seal.... ugh... It is mid May !!!