Aditional thermostate on 944 Turbo?
06-17-2001, 05:15 AM
#1
Instructor
Thread Starter
Join Date: Jun 2001
Location: Nevada City, CA
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
Aditional thermostate on 944 Turbo?
I was shopping around the internet on Pelican parts web site- my car is running hot so i was hoping to find a lower temp radiator fan switch- no luck there but in their thermostate section they mentioned that there was an aditional themostate on the 944 turbo. I am only awair of the one in the water pump. where is the other one? Could this be the source of my cooling problem? My cars temp goes up and down way too much, never quite overheats but she gets awfully close, thanks 
06-17-2001, 04:05 PM
#3
Nordschleife Master
The turbo thermostat isn't your problem, though I suppose that could be bad, too. It is right next to the main thermostat on the water pump inside the flange that feeds over to the turbo. Didn't you see that?
Anyway, you need to narrow down the problem. Does this up and down biz happen when you are going a steady 65 mph? The fan thermoswitch and fans should be irrelevant at that speed.
If it does then I would suspect the thermostat and get a new and/or cooler one. You can test the current one by putting it in a pan of water on the stove with a thermometer and watch when it opens and closes.
If you have a nice normal steady temp at 65mph then there could be several problems related to the cooling system and efficiency. The thermo fan switch could be opening when it is too hot - get a cooler one. You can test your current one but it is a bit harder to prop it up in water with the electrical leads dry and you need the volt/ohm meter clipped on the leads to see when it completes the circut. There are several available that will swith on starting way down in the low 70 deg C, so about 160F. Don't know if I would go that low, though.
If the thermo fan switch isn't the problem, then you are off on the elusive search: crud on the front of radiator fins or bent fins, corrosion/blockage in the radiator or cooling system, air lock in system, etc.
Do the 65 mph test and tell us what happens.
Anyway, you need to narrow down the problem. Does this up and down biz happen when you are going a steady 65 mph? The fan thermoswitch and fans should be irrelevant at that speed.
If it does then I would suspect the thermostat and get a new and/or cooler one. You can test the current one by putting it in a pan of water on the stove with a thermometer and watch when it opens and closes.
If you have a nice normal steady temp at 65mph then there could be several problems related to the cooling system and efficiency. The thermo fan switch could be opening when it is too hot - get a cooler one. You can test your current one but it is a bit harder to prop it up in water with the electrical leads dry and you need the volt/ohm meter clipped on the leads to see when it completes the circut. There are several available that will swith on starting way down in the low 70 deg C, so about 160F. Don't know if I would go that low, though.
If the thermo fan switch isn't the problem, then you are off on the elusive search: crud on the front of radiator fins or bent fins, corrosion/blockage in the radiator or cooling system, air lock in system, etc.
Do the 65 mph test and tell us what happens.
06-17-2001, 04:31 PM
#4
Instructor
Thread Starter
Join Date: Jun 2001
Location: Nevada City, CA
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
At 65mph the temp is rock solid. The up and down of the gauge is always during stop and go driving and idle. Weird thing is I already replaced the fan switch. It isnt a low temp unit, I was told that i could'nt get one by the local import parts store (thanks for nothing). Im going to order a lower temp unit today and see it that helps.
One thing i noticed is when i turn on any lights or fans the temp guage jumps a bit. does not make a huge difference but still...
One thing i noticed is when i turn on any lights or fans the temp guage jumps a bit. does not make a huge difference but still...
06-17-2001, 06:08 PM
#6
Nordschleife Master
Automotion has one they say goes on at 85 to 92 C. That seems pretty high and quite the error range in turning on. I would call around tomorrow and ask big outfits. Would be nice to know what yours is turning on at right now.
Anyway, you now know your problem is almost a certainty this switch if when in stop and go the car will kick down to normal temps once the fan turns on. It is just turning on at too high a temp. Take your time and find a cooler switch that you are sure is actually cooler.
The reason the temp gauge jumps around when you load the electrical system is because your wiring is less than great and you are having fair sized voltage drops as load increases. No bearing on this current problem.
Plenty is now in the archives on what to do about that, but cleaning up the grounds or installing new battery grounds is first on the list. Your battery cable is probably quite corroded and in places you can't see like a foot or so up the insulation. Then there is cleaning up the positive connectors in exposed places like sender sensors and the battery post. These also may have corrosion not only on the plug but also creeping up the wire under the insulation. It's what you get with 15 year old wiring which was marginal when it came fresh out of the factory.
Anyway, you now know your problem is almost a certainty this switch if when in stop and go the car will kick down to normal temps once the fan turns on. It is just turning on at too high a temp. Take your time and find a cooler switch that you are sure is actually cooler.
The reason the temp gauge jumps around when you load the electrical system is because your wiring is less than great and you are having fair sized voltage drops as load increases. No bearing on this current problem.
Plenty is now in the archives on what to do about that, but cleaning up the grounds or installing new battery grounds is first on the list. Your battery cable is probably quite corroded and in places you can't see like a foot or so up the insulation. Then there is cleaning up the positive connectors in exposed places like sender sensors and the battery post. These also may have corrosion not only on the plug but also creeping up the wire under the insulation. It's what you get with 15 year old wiring which was marginal when it came fresh out of the factory.
06-18-2001, 11:41 AM
#7
Track Day
Join Date: Jun 2001
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
One last thing to check before changing anything. At low speed or changing engine RPM the alternator has problems keeping the voltage constant. On my 951 the temp guage would react just like yours. Pop the hood and use a volt meter to measure the voltage between the NEGATIVE battery pole (Yes the negative one) and a ground on the engine. If the voltage reading is greater than about half (.5) volts then you have a grounding problem. If you don't have a meter then connect a jumper cable from the negative pole and attach it to a solid location on the engine and see if it cures your problem. If so the fix or add a new ground to the engine. Apparently this is a common 924/944 problem.
Tom C 87-951
Tom C 87-951
