TX Red

1983 Porsche 944 (my father's car) 90,000 miles

When he bought the car 2 months ago, the indicated normal operating temperature was about at the middle of the range.
It only got above this range when he was pulling a steep grade such as a mountain pass: The temperature returned to the middle of the range shortly after he started down the other side of the pass.
The coolant fluid levels are OK and are within the prescribed limits: there is no indication of coolant loss.
Gradually, the temperature has moved to higher equilibriums up the scale under normal operating conditions. It now reads at the lower limit of the high temperature range.
When he checks the engine coolant when the temperature gauge shows the engine is hot, the coolant is only mildly warm to the touch: also, the engine does not appear to radiate much heat. The hoses going to the radiator can be touched and/or squeezed, but are not extremely hot.
The auxiliary electric cooling fan does come on sometimes once he has stopped the car.
Any suggestions on what might be causing this? We have some general ideas, but need to get more specific. (Water pump, thermostat, sensor????)

ELLSSUU

I'm by far no expert, but if you have "cool" hoses then you may have a bad thermostat or water pump.

Hans

If it is realy overheating, then the head / cam tower will be realy hot.
You might also have some corrosion on the sender or contacts / grounds, fooling the reading.
TakeCare

K27w

Maybe try bleeding the system, could be a bit of air.

Type_LT

Bleeding the air is a good idea, see if the short hose that connects the waterpump to the tube running over the exaust manifold is hot this part bypasses the thermostat, I'm guessing it will be roasty toasty. If it's hot then the thermostat is probably bad.

TX Red

Great, thanks for the suggestions. I don't want to have to buy and replace 10 different parts before finding out what's wrong. So I will bleed the system, and check the hoses on the water pump. Anything else I should check?

993Maineiac

Bleeding the system is a good first step, but don't disregard the thermostat if the hoses are cool after the fan(s) has/have kicked in.

TX Red

[quote]Originally posted by 944Maineiac:
<strong>Bleeding the system is a good first step, but don't disregard the thermostat if the hoses are cool after the fan(s) has/have kicked in.</strong><hr></blockquote>


I am starting to have a pretty strong feeling it is the thermostat.