Porsche Repair: Porsche 944 Problems, degree thermostat, porsche 944

Question
I recently had my Porsche 944 painted, the whole process didn't go well, and it ended up taking 6 months.
Before the paint job the car ran well, didn't break, was properly maintained, and was a good car.
Now I've had it for just over two weeks and have run into problem after problem (a/c compressor going, exhaust going, starter going). When we got the car back we took it to get as flushed as possible.
When we got the car back the heat didn't work, the temperature control didn't work, and the two sliders that control where the air goes didn't work. I checked the fuses and they're good.
We had the radiator flushed, and I don't think the people did a very good job. First of all the temperature fluctuated from normal to the orange in like 15 seconds of it being stopped. It has taken 1 gallon of antifreeze. We had a new thermostat put in that now shows it as always running hot. I read online that you have to have the heat on to flush the radiator or else it will be full of air, which I think might be the problem.
Can you find any way to fix my heater problem to hopefully fix my cooling problem?

Sorry about the long message,
                            Matt


Answer
Hi Matt,

Don'tcha just hate it when the car comes home with more things wrong than when it left!  And none of the things now wrong were even involved with the reason it went away in the first place.  Exasperating!

Good idea to take one thing at a time now.  Heating should be easy.  Bet you've heard that before!

First, find out what temperature rating is on the new thermostat.  It should be on your bill.  If not, verify with the shop what rating was removed and what rating was the replacement?  For example, if you started with a 180 degree thermostat and all was well, as you said it was before the paint job, there should be no reason to change it for a 195 or a 160, etc.

Verify the thermostat is working properly by doing this test.

1.  Start and idle the car work the throttle awhile so the coolant temperature begins to rise.  2.  Keep the car idling.  3.  Locate the topmost large rubber coolant hose from the engine block to the radiator.  At start-up and til now the hose should be relatively cool because the hot (and getting hotter) engine coolant isn't yet moving past the themostat into the raditator to be cooled.  Your objective for this test is not to burn yourself!  Also, it's to verify that at a certain point that 'coolish' raditor hose will get hot as the thermostat opens and lets the hot engine water flow through that hose.  4.  At that point, when you feel the change in the hose's temperature, note the action of your coolant gauge.  5.  First, note the gauge reading when you determined the hose was hot.  While still idling, the gauge reading should start going down immediately after the thermostat opens...meaning the hot engine water is being effectively cooled by the radiator.  Right?  It won't go down to zero, but it should definitely reverse its upward path and level off to a "normal" range....  

Any other outcomes and you should talk to your mechanic...or write right back to me...I'd like to know what you find.  One step at a time OK?

Dave