93sc running too COLD!

BlackSC

Registered User
Hello all,

I know that the "What degree thermostat should I be using?" question has been beat to death around here. But this time I really want to look at it from a different angle. I recently got done replacing virtually every part in my cooling system except hoses to and from the heater core and the core itself. Radiator, hoses, water pump, sensors, and checked the fan out. So now it will run in town in 100 degree weather with the ac on and barely get to the halfway point on the gauge. However, in this process I stepped the tstat down to a 160 degree unit - which didn't help at all when I did it. But now, all is fixed even in hot weather and in cold weather (50-65 degrees ambient) the gauge never get's above the line by the 'C'!

So the question is this - are these symptoms possibly caused by the low tstat? If the gauge is barely lifting off I would think that the system isn't getting to 160 degrees where the thermostat is a factor. At any rate, I do plan to go back to the stock tstat or at least a 180 tstat but after reading about "sludge" problems due to running too cool I'm not sure which. So is it possible that the tstat is at fault here, and which tstat should I aim for to keep cool yet not frigid temps?
 
If your car is stock, you should be running a stock 195 stat. Your car should be running at optimal temps, for as long as the rest of the cooling system is in good shape.
 
BlackSC said:
which didn't help at all when I did it. But now, all is fixed even in hot weather and in cold weather (50-65 degrees ambient) the gauge never get's above the line by the 'C'!

Do you mean that in 100 degree weather you still run almost half way, after the changes and 160 tstat? And is it only in the cool weather you get around the C?
Doug
 
I had that same problem, but I had not done anything to the cooling system. But, my gauge was pretty much staying on "C". Turned out it was the connection to the sensor wasn't on fully. I think it was Aaron recommended that I check that and if fixed it! So, I would recommend that you check that connection. It is a single wire into a 90 degree bend right onto the sensor which is on the intake manifold towards the front left (drivers side).
 
Doug, that's exactly what I mean. I know that sounds fine but I don't want the car to run all winter without ever heating up and burning out the crap building up in the coolant passages. Yup, the gauge sensor is connected firmly. I suppose this weekend I'll probably toss the stock tstat in - I suppose they ran right from the factory and that's practically where this cooling system is now.
 
I suggest you put in a 180 t-stat to warm it up a little higher before it allows coolant into the radiator. During the fall and winter your stock fan settings will be okay, but it will run cooler in the summer if you install a adjustable fan controller to the low speed fan circut to make it come on at around 185 degrees.

Heat kills head gaskets.

David
 
Part of my heartburn with the SCs is this big difference you are experiencing. Runs normal in 100 degrees with a 160. With a hotter tstat I overheat in Texas summers. I have one car that runs cold, a 90 AOD recently bought. When I find out why I will do the same to the others, or just a bigger radiator and/or elect pump. Just wanted to see how the cold SC would do on the track last weekend and it was great. Engine stayed cold for 20 minute sessions on a road course. After 4 of those the AOD overheated, but was OK after cool down. Engine stayed cold and that is what I wanted to know as I run 5spds usualy.
 
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