pjburges

Don't know if the 928 has this problem - but on the 944 motor the temperature goes up not because of the slow movement of the vehicle - but low RPM's on the engine. If I keep the RPMs at 2K while stopping and going I run much cooler (below the half mark). If I just let it idle normal - it climbs to the half mark.

The oil temps always go down once the car is underway - which seems to help bring the coolant temps down a little too. Remember - if your headlights (and gauge backlights) are on it can sometimes skew the gauge reading because of bad grounds.

Randy V

Not yet.

I had actually gained improved cooling by moving the cooling fan shroud into proper position. The hanger tabs were sitting behind the radiator, reducing airflow through the radiator.

I'm still running a bit warm, but usually just below the third white line now.

mark kibort

the thermostat has nothing to do with overheating, unless it is defective.
you have a cooling issue due to coolant flow conjestion or air flow.

This is another topic riddled with misconceptions! I like the guys that put in some snake oil in their radiator and say how their car runs one marker line cooler!
once the system gets to temp, the t-stat is running wide open. 83c or 75c is the difference is that the t-stat starts to open with the different rated t-stats

GlenL

A cooler thermostat will give a cooler charge resulting in more torque.

I did hear a guy saying he liked a cooler thermostat so the engine didn't heat so quickly when coming to a halt in stop-and-go traffic. That was the only explanation that has ever sounded reasonable.

GregBBRD

Back when we actually were trying to make 944s "live", we had customers insisting that we install lower temperature thermostats, all the time. Unless you change the fan switch to a lower temperature fan switch, at the same time, don't expect very much change.

928 customers, when the weather turns from cold to hot, all question what the temperature gauge should be reading. Look at the gauge. The "middle" of the gauge is 170 degrees. The "third" white line is 210 degrees. The thermostat doesn't open until 181 degrees (83C). The fan switch turns on the "first stage" at 185 degrees (85C). So, the absolute "best" that could occur is for the temperature needle to "sit" halfway between the middle and the third line. However, note that the fan switch is on the left side of the radiator and the temperature sender is on the water crossover just before the water leaves the engine and goes into the radiator....on the right. The radiator, even without the fans running, is going to remove heat from the coolant....the fans will not come on, until the temperature of the water leaving the block is significantly over the 185 degree mark.

Over the years, I've seen more than just a couple of 928s. It seems that the average "normal" indication on the temperature gauge is about 2 needle widths below the third line. This is where I tell everyone their car should be running, in the summer.

The "electric fan" 928s have a "second" stage inside the fan switch, which controls the fans. This switch closes at 93C. This will switch the fans from "normal" speed to "high" speed. If you hear the fans running at "high" speed more than in really severe situations, you need to think about doing something with the cooling system...otherwise, it is probably fine.

Go clean the "contacts" at the temperature sender and the wiring loom. That may make your gauge read a needle line width lower.

GregBBRD

Mark:

You need to put some thermostats into water with an accurate thermometer....the numbers on the thermostats are when they "start" to open....not when they are full open. All the German thermostats are the same way...coolant, oil, transmission, etc.

mark kibort

typo. I agree. starts to open.

vze2jshn

For what it is worth, I found that the lower temp thermostat when installed in my '78 would not allow the coolant to get hot enough for comfortable heating temps in the winter on the highway in NJ.