Car Problem Reports

Audi A8 Quattro Overheating Due to Failing Thermostat

Audi A8 Quattro Problem
34 Reports
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Model Years Affected: 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

Engine Affected: 4.2L V8

Average Mileage: 95,798 mi (24,000 mi - 175,000 mi)


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

  • Visitor, , 4.2L V8, 75,000 mi

    Engine suddenly overheated significantly without any previous warning or coolant leakage. Failed thermostat replaced.

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  • Visitor, , 4.2L V8, 24,000 mi

    Thermostat failed closed

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  • Visitor, , 4.2L V8, 116,500 mi

    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.

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  • Visitor, , 4.2L V8, 165,000 mi

    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 fix done.

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  • zedrick, , 4.2L V8, 26,000 mi

    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.

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  • Visitor, , 4.2L V8, 118,480 mi

    It just started to overheat.

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  • Visitor, , 4.2L V8, 140,000 mi

    Engine overheats unless heater is on HI. Not yet repaired looking for a reasonable and qualified repair technician

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  • Visitor, , 4.2L V8, 117,089 mi

    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

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  • Visitor, , 4.2L V8, 68,000 mi

    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!

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  • Visitor, , 4.2L V8

    The the 2004 A8L with 64,500 suddenly overheated. I drove it home (about 3-4 miles) quickly and will bring it in or have it towed in for service tomorrow.

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