Another Temp question

[fatboy007]

I was wondering What is the optimal engine operating temps? My 89 94n/a 139.000 miles is running consistently 100C or 212F. I'd was told by one porsche shop this normal. I think it's a little hot and the days where cooler this week.
I replaced -
Waterpump, not spinning on shaft
thermostat 180F
temp sending sensor
lower temp fan switch
Radiator hoses
Flushed and bled
No mixing of oil and coolant

Thanks!

[Techno Duck]

Both my 951 and n/a have a temp sensor in the upper radiator hose which is the hottest point of the cooling system essentially. I normally see between 180-185*F running on the street with ambient around 70*F. Fans kick in around 190*F at idle and cool right down. This is using a digital gauge, not an analog so its accurate to single digits.

This was using the low temp fan switch and stock range thermostat. When i ran a stock range fan switch, i was seeing temps creep up into the 205*F range when sitting at idle and takes much longer to cool off. 212 is still fine, but in my opinion on the high end of the normal range. Double check that the gauge is working accurately, clean your grounds and also clean up the connectors on the cylinder head temp sensor. Mine were heavily corroded.. i ended up completely replacing the spade connectors which helped settle the 'bouncing' gauge. Also double check your A/C condenser and radiator fins are not clogged with road debris.

My dash gauge is usually under the 1st mark and i dont think i have ever seen it go past the 1/2 mark during normal driving, even in the dead of summer. Personally i think the dash gauge reads a little bit low. I have a theory that this is the same reason the gas gauge reads 3/4 of a tank on almost every late interior 944 i have ever seen. I think the needle slips on the peg a little bit after 20 something years causing slightly lower readings. Thats just my theory .

[John_AZ]

If you flush your radiator and condensor, spray some Simple Green or similiar product on and wait for a couple of minutes.

Take a hose from the engine side with a nozzle and spray OUT the front. Something like an old insect spray wand from a small home tank sprayer works well if adapted to a garden hose. (remove the front tip)

If you spray from the front to the engine, you are shoving the bug bodies and wings deeper into the fins and you may actually raise the operating temp.

GL
John_AZ
1988 924S + 1987 924S

[smokin_944]

There are a variety of different temp ranges available for thermostats and thermal switches on the 944. If your cooling system is stable and in excellent running order, and is a 2 fan system, you should be able to more or less dial in the operating range you want (within reason). If you want your 89 to run cooler, use a 160 degree F Tstat (71 degrees C) and a 140/149 degree thermal switch (60/65 degrees C). This will drop your temp very considerably. In 70 degree F weather, my 84 runs at 170 to 176 degrees F with that setup.

[mikepellegrini]

A couple of weeks ago, I dismounted the fans on my NA and using compressed air, I blew the bugs out of my radiator. Actually, I didn't see any bugs, but there was an awful lot of sand/dirt. I spent maybe an hour on it.

It seems like it runs a little cooler now. Plus my A/C seems cooler too.

It makes sense if you open up more air passages, the radiator/condensor will cool more efficiently. The older/crapier the radiator, the more gain, I'd think.

[fatboy007]

I like to thank everyone for their great advice, these are the things I didn't think of.

Thanks Again!