OK, so heres the story. If I drive the car on the open highway I can go on forever without overheating, only getting one line past the center of the gauge. If I get caught in traffic or drive on small streets (low speed low revs) the gauge goes to the line before hot and the buzzer goes off. I usually turn the heat on full blast and the car cools back down. I already replaced the clutch fan and the problem remains

So as of yesterday the yellow coolant warning started staying on all the time and then turns to the red warning when the car heats up. I checked the car with the vag-com today and it tells me the coolant temp sensor is bad.

If Im correct this would be causing the yellow warning right? But now Im wondering if my car is having any problem at all. I already have an appointment(with money down) to have the waterpump/thermostat ect replaced on tuesday.

So is there any chance the problem has been the sensor all along? Is there any way to tell besides changing the sensor? (which I dont have time to do)

Thanks in advance for the help.

 

a coolant temp sensor would make sense given the symptoms described. however i would think the clutch fan would move enough air to prevent overheating. however, if the temp sensor was bad, it could fail to turn on the electric fan mounted in front of the radiators. i know on my C5 that fan is moving alot of air on a hot day.

so, being that you know the coolant temp sensor is bad, i'd replace that and see what happens before you pay a garage to replace the thermostat and waterpump. out of curiosity, what did they quote you for labor?

 

Im driving an hour or so upstate NY and its $650 w/ parts included. Im getting the cam seals, valve cover gaskets ect (the common oil leaks) done for an extra $150. I think ill let them do that stuff regardless since its good to know its all done. I woudl test the sensor first if I had time but I cant get the sensor till tuesday and I already paid them for the parts.

 

if it helps here is the error


16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal
P0116 - 35-10 - - - Intermittent

 

so how did this one go?

 

wish I could find folks to pay me $ 150 for removing and fastening back on 12 bolts, and attach 2 gaskets on the valve covers.
Is that price only for labor, or does it include the gaskets?

 

Thats the labor and the gaskets.

More on my coolant problem:

I read on another forum that I shoudl use the vag-com to see enigne values(iirc) 004 and 006 and they shoudl read almost the same. Mine read dramatically different( about 60 degrees) so according to them its a bad sensor. But I dont know if I should trust this info.

 

sounds like a bad sensor to me. the drastically different readings support that. will is solve your problem? possibly. getting the waterpump, cam seals and the rest you mentioned is probably a pretty good idea, but don't be overly alarmed if that doesn't resolve your issue without replacing the sensor.

 

But if the sensor was bad wouldnt it be wrogn all the time. The car only "overheats" when the car is sitting still, not when moving which supports a bad waterpump. ALso is it possible that the sensor just went bad, since the yellow warign didnt start going off until a day ago whle the car has been overheating for weeks.

 

If the sensor that turns on the fans when things get hot is bad you would over heat when driving slowly