What range of coolant temp have you measured?
04-13-2004, 12:01 PM
#16
Three Wheelin'
Originally posted by 944S Boyeee
Does the 928 have fans that run after the car is shut down? I've had my 89 S4 for like a week and the temp guage is always just below the third white line. In traffic, it sit right on the line, but never goes any higher.
When I shut the car down, no fans run. On my 944, I always had fans running after shut down.
Does the 928 have fans that run after the car is shut down? I've had my 89 S4 for like a week and the temp guage is always just below the third white line. In traffic, it sit right on the line, but never goes any higher.
When I shut the car down, no fans run. On my 944, I always had fans running after shut down.
04-13-2004, 01:08 PM
#17
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Garth,
Rechecking the o-ring and distance between thermostat disk and rear seal is the reason I will be going back in there. I tested both old & new (sic.) thermostats in a pan of water on my stove. New thermostat was from one of the Big Three, so at least I know it's the right one.
I guess I agree with you on the impeller... it won't get checked until the next scheduled timing belt job (unless something dramatic happens), that's for sure.
Doug,
I'll need to check the oil temps, but the coolant temps always crowd or exceed 90C.
That web page seems to be missing?
Lag,
I was fastidious about insuring that there was no recirculation; all seals are in place & make contact. Behavior also occurs with hood open, idling.
=================================================
My fan controller supplies 12 volts to the fans. I believe that some later models supplied full battery voltage, 13.5+. If I ever stumble upon one, I may be able to pick up another 10% airflow from updating that. I tried using the output of the controller to switch relays to apply full battery voltage, but the protection circuit in the controller was triggered. I could do a little more engineering and run a load through a dummy resistor, etc., but the marginal benefit doesn't seem worth the effort & complexity (and I know I need to focus on finding the problem, not hacking a solution).
Rechecking the o-ring and distance between thermostat disk and rear seal is the reason I will be going back in there. I tested both old & new (sic.) thermostats in a pan of water on my stove. New thermostat was from one of the Big Three, so at least I know it's the right one.
I guess I agree with you on the impeller... it won't get checked until the next scheduled timing belt job (unless something dramatic happens), that's for sure.
Doug,
I'll need to check the oil temps, but the coolant temps always crowd or exceed 90C.
That web page seems to be missing?
Lag,
I was fastidious about insuring that there was no recirculation; all seals are in place & make contact. Behavior also occurs with hood open, idling.
=================================================
My fan controller supplies 12 volts to the fans. I believe that some later models supplied full battery voltage, 13.5+. If I ever stumble upon one, I may be able to pick up another 10% airflow from updating that. I tried using the output of the controller to switch relays to apply full battery voltage, but the protection circuit in the controller was triggered. I could do a little more engineering and run a load through a dummy resistor, etc., but the marginal benefit doesn't seem worth the effort & complexity (and I know I need to focus on finding the problem, not hacking a solution).
04-13-2004, 01:24 PM
#18
Range Master
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The airbox on the SC install blocks air flow through the a small %age of the radiator......however, standing still that should not make any difference.
I do note that my car runs considerably cooler if it is moving than if it is standing still. I get readings over the top white line at idle, (but not in the red zone), and 1/8 inch below the top white line when cruising. I live on the top of a mountain. Climbing the 700 feet from the valley up to my farm runs the temp up over the last white line.
Where are people getting these IR temperature meters, sounds like a neat tool to have.......an oil temp gauge sounds like a good idea also......
I do note that my car runs considerably cooler if it is moving than if it is standing still. I get readings over the top white line at idle, (but not in the red zone), and 1/8 inch below the top white line when cruising. I live on the top of a mountain. Climbing the 700 feet from the valley up to my farm runs the temp up over the last white line.
Where are people getting these IR temperature meters, sounds like a neat tool to have.......an oil temp gauge sounds like a good idea also......
04-13-2004, 01:47 PM
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Gretch, sounds like you are running warm, too. Welcome to the club. 
Sears has an IR for <$50.
Agreed on the gauge, but my cockpit is starting to look like the Space Shuttle, as it is...
Sears has an IR for <$50.
Agreed on the gauge, but my cockpit is starting to look like the Space Shuttle, as it is...
04-13-2004, 06:34 PM
#21
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Hi Old & New,
at 90C the thermostat is not yet fully open and only about halfway between the closed and fully open points. What temp does the IR reader show the vee and valve covers to be at that point?
The thermostat's late full open point of 98C is significant in this engine as you need to consider that the oil cooler's thermostat only opens at 87C and is probably fully open near 95+C
Don't be fooled by the gauge
Regards
at 90C the thermostat is not yet fully open and only about halfway between the closed and fully open points. What temp does the IR reader show the vee and valve covers to be at that point?
The thermostat's late full open point of 98C is significant in this engine as you need to consider that the oil cooler's thermostat only opens at 87C and is probably fully open near 95+C
Don't be fooled by the gauge
Regards
04-13-2004, 10:30 PM
#22
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I just tested the used Wahler 75C thermostat. I measured the gap at different temperatures:
149F / 65C crack
158F / 70C 0.20"
167F / 75C 0.27"
176F / 80C 0.38"
185F / 85C 0.51"
194F / 90C 0.55" (max)
According to these numbers (which are averages of several cycles, all data +/- 0.05"), my thermostat is wide open idling at operating temperature and the temp is controlled by the cycling of the fans (which are usually on).
I have yet to measure the vee and valve covers.
149F / 65C crack
158F / 70C 0.20"
167F / 75C 0.27"
176F / 80C 0.38"
185F / 85C 0.51"
194F / 90C 0.55" (max)
According to these numbers (which are averages of several cycles, all data +/- 0.05"), my thermostat is wide open idling at operating temperature and the temp is controlled by the cycling of the fans (which are usually on).
I have yet to measure the vee and valve covers.
04-13-2004, 11:13 PM
#23
Burning Brakes
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Hi Old & New,
Thanks for posting the progressive temperatures for the 75C thermostat
For normal use I wonder if the 75C thermostat is really such a good idea
After doing the temperature testing I would never use one in my car!
Regards
Thanks for posting the progressive temperatures for the 75C thermostat
For normal use I wonder if the 75C thermostat is really such a good idea
After doing the temperature testing I would never use one in my car!
Regards
04-14-2004, 01:46 AM
#24
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Understood / agreed. It is what I took out and replaced in kind. One of the Big Three told me they sold 3:1 over the higher temp units & in a pinch I went with it. (Addendum: Previous post about the "right" thermostat from one of Big3 was to highlight the fact that I found a couple of aftermarket units to have a substantially smaller diameter back disk... possible improper occlusion of the rear seal!)
...but given the situation with this cooling system, I don't think its rating is any more than academic fodder at this point.
When I straighten this out, I will be putting the higher temp unit in.
Is it possible to install the thermostat O-ring improperly and still seal the housing? I'm sure I didn't do that, but I'm wondering why it is discussed on the forum...
Next I will put a boiler plug in the block and remove the t-stat to rule it out as part of the problem.
I'm running four 900 cfm fans. I don't suppose anyone has specs on the stock fan airflow or coolant pump flow???
...but given the situation with this cooling system, I don't think its rating is any more than academic fodder at this point.
When I straighten this out, I will be putting the higher temp unit in.Is it possible to install the thermostat O-ring improperly and still seal the housing? I'm sure I didn't do that, but I'm wondering why it is discussed on the forum...
Next I will put a boiler plug in the block and remove the t-stat to rule it out as part of the problem.
I'm running four 900 cfm fans. I don't suppose anyone has specs on the stock fan airflow or coolant pump flow???
Last edited by Old & New; 04-14-2004 at 03:01 AM.
