Audi
A8 Quattro
50

Check Engine Light and/or Engine Overheating Due to Failed Thermostat on Audi A8 Quattro

Problem Description and Possible Solution

The thermostat may erratically stick open or closed. The can result in illumination of the Check Engine Light and/or engine overheating.

Problem Data
RepairPal Verified
Average mileage: 98,683 (24,000–198,000)
Engine affected: 4.2L V8
14 model years affected: 1998, 1999, 2000, 2001, more2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
50 people reported this problem
Comments
Viewing 1 - 20 of 21 comments
Coolant level is full. No leaks. Temp gauge moves to red after 7 miles driving from cold start.
Engine suddenly overheated significantly without any previous warning or coolant leakage. Failed thermostat replaced.
my a8 qquatro overheats but does'nt read it on the gage. i had a new waterpump installed> it leaks a little somwhere on the left when parked and turned off and the cooling fas don't continue to cool it when turned off. don"
't know what to do please help.
I had my Audi A8 Quattro 4.2L Parked in my heated garage for 6 weeks i drove it out and after about 15 miles it started running above normal temperature i had to turn the interior heater on to maximum to get the temp back to normal my audi main agent said i needed a new water pump and thermostat at a cost of £1675.53 i was not happy this obviously must be a manufacturers design fault i mean you would not think a £57000 car would need a water pump and thermostat after a mere 26000 mile and it is not soughted yet as i think Audi should rectify the problem or at least meet part of the cost.
Thermostat failed closed
check engine light came on, pulled entire front of motor to get to thermostat replaced radiator first thinking that could be cause of overheating. replaced timing chain since it was due to be done at 70k anyway. a $150 thermostat in a chevy, costs over 3k in this Audi due to all the items that were done along the way...
Thermostat stuck in closed position, engine overheated. Dealer replaced thermostat. In order to do so had to remove timing chain and water pump to get at thermostat. Replaced timing chain and water pump as long as it was all torn apart. Expensive repair for a thermostat. Thought they normally failed in the open position!
Check engine light. Codes said failing thermostat. $871 to fix. Recommended same time do the timing belt, serpentine belt, and water pump with the thermostat, quote, $2065.
Check Engine light on...told by local mechanic that thermostat is stuck open (or so I'm told)...also told it's very expensive to fix, since the whole front end needs to come off to get to it...no fix done.
Car overheat after driving about 3-10 miles. Fan very loud . When heat is Hi it drives okay .
Failed Thermostat
Coolant added after overheating, didn't buy wrong kind just didn't fix problem. Then my car overheated again and the gauge went off the malfunction light came on. I think the temperature gauge is the problem but if it is then does this mean my car is not actually overheating or is it? I put the heat on to lower the gauge which worked for awhile before this but my guess is check out oil, temp gauge, then fans (hear them running or not) then water pump be the problem?
Every time I get out car it feels real hot and inside also really hot without AC on.
2007 S8 over heating. Bought in January, I think "regular" coolant was used previously, flushed and filled with GOOD stuff, still over heating. Thermostat?!?
Thermostat sticking
I'm having the exact same problem.
Warning light comes on if it is cold out and stays on for about a minute. As the weather became hotter it then began to come on while driving and the temp gauge stats to spike. Opening the reservoir cap and release some pressure and it comes back down and runs normal temp. This happened twice, which makes it appear that the thermostat is stuck closed and is released with the pressure.
It just started to overheat.
Engine overheats unless heater is on HI. Not yet repaired looking for a reasonable and qualified repair technician
Car periodically seems ( per the gauge ) to be running too warm
Now the check engine light came on
Mechanic told be previously that it's an expensive job to fix and just get used to topping off the coolant from time to time