Billyboy746

Thermostat Question
4 years ago I rebuilt my 71 Olds 350, & got a new radiator with shroud. I have headers with dual exhaust.
When it is hot outside....80 and up.....if the car sits for a while running like in a line or waiting on a train,
it runs a bit hot. I have turned the heater on and brought it down some.
If the car is driving, it usually doesn’t get hot. Would changing the thermostat help? Not sure what is in
there but should it be a 180?
Do I have to get an electric fan for the radiator? It has always run a little warm when idling even before I had the
work done, but it did have a cooling fan that the rebuilder said I really didn’t need.
Any suggestions?
Thanks, Billy

Vintage Chief

I have the same engine.
I'm not at all understanding what "...runs a bit hot..." represents. Without specific temperature readings, "...runs a bit hot..." is virtually meaningless.
You turned on the heater and brought it down some? Down some from what temperature?
The normal thermostat is 180°.
If it isn't boiling over and puking coolant it's probably w/in temperature operating range.

oldcutlass

What is the actual temperature at extended idle and cruise speed?

Billyboy746

joe_padavano

Let's not forget that at 16psi, the coolant boiling point is about 250 deg F. That's why cars have a pressurized cooling system.

Billyboy746

Sorry about the vague running hot. My temp gauge is like the fuel gauge. Cold, a mark at 1/4...1/2....3/4.....and Hot.
It runs at 1/2 and up to 3/4 if at idle for a while on 80 plus days.
I just don’t know if this is normal as on our newer cars the temperature gauge usually never gets hotter than 1/3 of
the gauge.
I hope this helps with explaining the running hot.
Billy

JOHNNYOLDS442

Yeah the guys are right.
What is running Hot? alittle antifreeze spitting out versus alot?
check cap and thermostat.

Billyboy746

I’ve never had any antifreeze puking out...but isn’t that too far to go on the hot side?

joe_padavano

You have absolutely no idea how that gauge is calibrated, or if it is even accurate. Personally I wouldn't bat an eye at this. If you're really losing sleep over it, get an IR thermometer and figure out exactly what the temp is at that reading, then decide if you are worried about it or not. If "3/4" represents a 220 F coolant temp, that's completely normal.

oldcutlass

You can get a mechanical temp gauge and install it temporarily to see what your temps are. Frankly as Joe P. said, I would not worry about it.

Billyboy746

Thanks all for your help with my heating concern. I guess as it doesn’t have numbers on the gauge and only
1/4 marks, I get concerned when it goes over the 1/2 mark. The newer cars barely go over 1/3 on hot days even
with the air conditioning on.
I may check the temperature if it goes over 3/4 on the gauge otherwise I won’t worry.
Have a great holiday to you all.
Billy

FStanley

Buy a infrared temp gun to check temps


Put a piece of cardboard in front of the radiator at idle


then watch gauge rise and check with gun at intake temp sensor area


then you'll know what the gauge means.. C, to H


for cooling troubleshooting look here


https://classicoldsmobile.com/forums...e-heat-105434/

cjsdad

Heating up is heating up, regardless of the markings on your temp gauge. If your engine gets hotter when stopped in traffic but then cools back down when moving it is possible your fan clutch is going bad. The fan clutch is supposed to engage and pull more air through the radiator when the engine heats up. Or more to the point, when the air temp coming through the radiator gets hot, and then disengage when the air cools down. Check the fan clutch before starting the engine and get a good feel for how easy it rotates, take it for a drive and get the engine hot, let it set in the driveway for a bit until the temp starts climbing, shut it off and check the fan clutch again. If it is not more difficult to turn when hot, get a new one.