teleloco9

i have a 85 944 stock motor setup. i thought the thermostat was stuck open since it ran cool on the hiway and in the winter. i went to put a new one in and saw there was not one in there (and no retaining ring). i installed the thermostat and filled the cooling system as per recommended procedure jack up front. bleed screw it took just shy of 2 gallons and i thought it was ok.

drove the car and now the fans dont come on until the 97 deg mark vs 89 deg mark the car will hold at idle at the 97 deg mark but driving the car the temp will go up into the 105-120 region.

the car ran pretty normal in summer temps with the fans coming on at the 89 deg mark and would cool the car back to the 80 deg mark

i tested the thermostat it opens about 3 mm at 80 deg, i burped the system by squeezing hoses ran with bleed screw open just coolant flowing out several times and nothing changes

the heat in the car is robust but the lower hose from radiator to thermostat doesnt get very hot after the fans come on it feels cool

the coolant drains easily from the radiator when the lower hose is removed from thermostat housing...

is there a way to test the water flow or water pump function?

mytrplseven

IMHO:
Are the fan thermo-switches and the thermostat the same temp value? Are they the proper value for your car? When you bled the system, did you do it with the heater selected to "on"? I've heard and also did this myself, to raise the car, driver side up to ensure all the air is out of the system. Does the system cool down with the A/C on (turns the fans on)?

specsalot

I've bled the coolant system a few times (when changing coolant). It does seem to be faster / easier with the front of the car elevated on ramps.

odonnell

Another trick (in addition to jacking up the front) is to bleed it, then run the car up to the temp where the thermostat should have opened. Then bleed again. This gets any air that may not have been bled the first time because of the smaller loop.

teleloco9

as stated earlier the car worked as should be w/o the thermostat in there in the fall. so i believe the switches and sensors and thermostat are as should be, the fans come on and keep it at the 97 deg mark or will cool it from the 105 mark down to 97 but stay on like they should, and they stay on post shut down to keep cooling.

i did it with the front of the car up and the bleeder was weeping coolant only....cold. hot several times. the cooolant lelvel was same weeping out of bleeder as was in expansion tank. there's no way this is air lock. i didnt remember how much thermostats open but i remember it more than 3mm like this one which wood be a flow restriction but shouldnt be that serious....im thinking i will flush it and run it with straight h2o and drain it and try to feel flow by squeezing lower hose with no thermostat.

i'm thinking restriction or poor flow from pump.....which is why the previous owner had no thermostat in there. i didn't drive the car in the winter b/c the temps never got up with out idling and got way cold when moving.

it seems like you should be able to tap a valve into a junction and open it before its too hot to see what type flow you get out of the system.

how common are pump impeller and pully spinning on shaft etc types of issues?

thanks alot for input! now that my road is almost open over the pass i want to drive this car!

teleloco9

also the heater valve was wide open and the heat was very robust which made me think the pump was pumping ok.....

william_b_noble

why does 97 deg bother you? my recollection, which may be fading is that the car runs warmer than that, a pressurized system can run hotter than the sea level boiling temp of water. What does the factory service manual say for temperature?

teleloco9

97 is 3rd mark, i could live with that but car is at 105 while driving uphill with 15 deg outside temps, when its 30 deg the car will overheat and it doesn't correspond with the fan switches

odurandina

I've never seen so many cooling system threads in one week/month....

jaysus what a bunch of ****boxes.... my car included. 2 blown H20 pumps in 2013.

is that a record???

and count my car among the damn, this effiing moneypit motor runs hot category.

just one more reason to say, "good riddance ****scum Porsche motor."

course, I could have posted my rant on 70 other threads...

I had to let off some steam. just sorry your thread had to be the one.

message to the board: "go V8."

mytrplseven

I'm wondering if you have a radiator hose that's collapsing or a water pump that isn't being driven by the timing belt (belt tension). Rule of thumb: if you can barely turn the w/p pulley by hand then the timing belt tension is about right. If it turns easily, then your belt tension is likely too loose. Also check belt for obvious contaminants (oil, water, etc) on back-side of belt causing slippage on the w/p.

odonnell

Is the system itself holding pressure?

Replacing the expansion tank cap fixed my pressure problem.

konakat

You've been controlling your outbursts pretty well lately, I won't give you a hard time about this one. I do find it interesting that different issues seem to be 'popular' for a month or two, then another will take it's place. Idle issues were all the rage in the fall, now it seems like cooling is the en vogue issue.

teleloco9

i did retention the timing belt when i did the balance shaft tensioner, ill check that out, i did the 90+45 deg twist tension upon recommendations of the group. the belt was clean then and no leaks....ill check it out,
thx