Overheating 4.2
10-12-2003, 07:26 PM
#11
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Re: Good point, unless the A/C compressor automatically kicks out on engine high temp
A forum search yeilded the following note in several other posts regarding this subject matter:
"One interesting feature, the computer shuts the A/C down as you approach an overheat condition."
Posted by quattroconvert on 2001-06-21 22:34:59
"One interesting feature, the computer shuts the A/C down as you approach an overheat condition."
Posted by quattroconvert on 2001-06-21 22:34:59
10-12-2003, 07:27 PM
#12
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If you are driving on the highway and it overheats....
...there is a very good chance it's the thermostat. As I mentioned, a few of the 5v 4.2 motors on the A8 have reported the same overheating, and after extensive troubleshooting (we went through everything) it was the themostat.
I'm not saying go replace it tomorrow, but see how it overheats, and listen for the fan to go into hyper mode when it gets above the 11 O'clock tick on the water temp. If it does go into fast speed, then you know the fan is working. And yes, a temperature sensor controls the speed of the fan.
pw
I'm not saying go replace it tomorrow, but see how it overheats, and listen for the fan to go into hyper mode when it gets above the 11 O'clock tick on the water temp. If it does go into fast speed, then you know the fan is working. And yes, a temperature sensor controls the speed of the fan.
pw
10-12-2003, 07:29 PM
#13
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Definitily. think how much heat the coils of the AC are producing, and how they are sitting there
near the radiator getting hot, and keeping the heat in the radiotor from getting out.
the minute you turn on the A/C, the aux fan has to kick in full blast
the minute you turn on the A/C, the aux fan has to kick in full blast
10-12-2003, 07:32 PM
#15
AudiWorld Super User
Not correct
The electric fan does not have to be on full blast to have adequate A/C.
And if it's a relatively cool day, the A/C can run and put almost no thermal load on the condenser because there is no load on the evaporator.
Now if he was in Death Valley today, then you have a very good point.
pw
And if it's a relatively cool day, the A/C can run and put almost no thermal load on the condenser because there is no load on the evaporator.
Now if he was in Death Valley today, then you have a very good point.
pw
10-12-2003, 07:33 PM
#16
AudiWorld Super User
An A8 thread on overheating and the thermostat being the culprit
It was a 00, five valve motor. The 4 valve motors do not seem to have as many problems with the thermostats as compared to the 5 valve motors.<ul><li><a href="https://forums.audiworld.com/a8/msgs/21224.phtml">https://forums.audiworld.com/a8/msgs/21224.phtml</a</li></ul>
10-12-2003, 08:11 PM
#17
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At a steady 50-60 mph, ...
the car shouldn't overheat even with both fans off. At those speeds, waste heat being dumped into the cooling system is very low, and you've got good air flow thru the radiator.
10-12-2003, 08:21 PM
#18
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Re: that is probably the right answer. if the fans are functioning correctly
Well, I dont know that the fans are functioning properly, they dont seem to be kicking in to high speed when the A/C is on (or when the A/C is off for that matter). Either way the car is still overheating with the A/C off, and while traveling at steady sppeds which i would think provide just as much cooling as the fans. So maybe I have 2 problems?
10-12-2003, 09:40 PM
#20
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AC and coolant temp go at the same time? Sounds a lot like...
What happened on our A4: the AC went warm, the temperature started up, then CEL and other lights came on.
What had happened: the belt idler pulley seized and the belt stopped turning. Soon, it shredded and was quite obvious when my wife reached the first service station.
Perhaps your was about to have the same fate?
Repairs were not expensive, and covered by extended warranty. There was no evidence of overheating.
What had happened: the belt idler pulley seized and the belt stopped turning. Soon, it shredded and was quite obvious when my wife reached the first service station.
Perhaps your was about to have the same fate?
Repairs were not expensive, and covered by extended warranty. There was no evidence of overheating.