update 4: overheating
01-26-2006, 09:47 PM
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update 4: overheating
background:
1998 A4 2.8 Q. Year ago did 60k mile service, timing belt,water pump, thermostat, cam seals. Immediately after water temp guage routinely would meander above "noon" (straight up) where it never had before in 7 years. Summer rolls around and A/C cuts out in ~80F weather. Replace water pump, viscous coupling (thermocoupling that engages the mechanical fan), the thermostat. Winter comes, going up hill in 10F blowing snow at 45mph water temp guage goes to the 2nd major tick mark and coolant overheat light comes on. Replace thermostat again, and the water temp guage. All are OEM parts. Water temp guage still pushes 2nd tick mark but doesn't quite get there, on uphill climbs.
Yesterday the radiator was replaced. Problem still is happening where water temp guage goes to 1.5 ticks. It does it everytime I stop at a red light. And does it seemingly randomly when driving at a consistent 60mph speed on the highway. Up to 1 tick mark, down to "noon", up to 1.5, down to noon, etc.
So everything related to the cooling system has been replaced. WTF is going on???!! Help!
1998 A4 2.8 Q. Year ago did 60k mile service, timing belt,water pump, thermostat, cam seals. Immediately after water temp guage routinely would meander above "noon" (straight up) where it never had before in 7 years. Summer rolls around and A/C cuts out in ~80F weather. Replace water pump, viscous coupling (thermocoupling that engages the mechanical fan), the thermostat. Winter comes, going up hill in 10F blowing snow at 45mph water temp guage goes to the 2nd major tick mark and coolant overheat light comes on. Replace thermostat again, and the water temp guage. All are OEM parts. Water temp guage still pushes 2nd tick mark but doesn't quite get there, on uphill climbs.
Yesterday the radiator was replaced. Problem still is happening where water temp guage goes to 1.5 ticks. It does it everytime I stop at a red light. And does it seemingly randomly when driving at a consistent 60mph speed on the highway. Up to 1 tick mark, down to "noon", up to 1.5, down to noon, etc.
So everything related to the cooling system has been replaced. WTF is going on???!! Help!
01-26-2006, 10:05 PM
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overheating
Have you checked the coolant temp sensor($8) at the back of the head and the secondary fan sensor($30). The two should have been replace when the rad is done. They are both trouble makers. Both are easy to replace DIY.
01-26-2006, 10:26 PM
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Re: overheating
coolant temp sensor has been replaced three times. secondary fan sensor i haven't heard of, so i don't know what that is. there is a thermostat that has been replaced twice which is basically just a valve that controls the flow of coolant. cold coolant, closed valve. warm coolant, partially open valve. hot coolant, open valve.
however the mech says he confirmed both the mechanical and electric fans are working correctly. yet when i'm at a stop light with windows down, i can hear a "click" in the viscinity of the fuse box and the electric fan comes on and then 3 seconds (literally not more than 5 seconds) another click and the fan goes off. so maybe there is still some issue here as i haven't heard this mentioned (even though I've mentioned this clicking thing and 3 seconds of the electric fan being on several times he hasn't sounded like he's concerned with it)
but even if both fans weren't running, i don't get how 60mph of airflow won't cool this car properly. i'd think the fans are irrelevant at that speed.
however the mech says he confirmed both the mechanical and electric fans are working correctly. yet when i'm at a stop light with windows down, i can hear a "click" in the viscinity of the fuse box and the electric fan comes on and then 3 seconds (literally not more than 5 seconds) another click and the fan goes off. so maybe there is still some issue here as i haven't heard this mentioned (even though I've mentioned this clicking thing and 3 seconds of the electric fan being on several times he hasn't sounded like he's concerned with it)
but even if both fans weren't running, i don't get how 60mph of airflow won't cool this car properly. i'd think the fans are irrelevant at that speed.
01-27-2006, 04:41 AM
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Maybe the radiator
I don't think its a fan issue at those temperatures, because at 10 degrees, your car should not be that hot, even if the electric fan was off and the clutch fan was weak. I think maybe the radiator is completely clogged up, or there is a blockage somewhere in the cooling system. Has it ever had leaks? Have you ever used "stop-leak"?
