My lovely A6 is showing the Temp warning sign on the dash ! Its a 1997 model and i have recently replaced thewater pumpunit when it started over heating. Then a few days later warning light came on again but the temp gauge was not going over90 so i replaced theengine heat sensor ! no faults are showing up on the digisnostics computer ??? Im lost now when engine is hot i can open the coolant tank and not muc presure is released which might telll me that the headis not gone no smpke from exhaust etc

Any ideas will be greatfully welcomed i can only think of electrics as a problem or the fact that the water pump went might tell me water was used instead of coolant which might hav caused some hot spots around some parts of engine

Many thanks

 

Did it overheat before? Sometimes when cars overheat and than you fix them the sensor will still think it's overheating on special occasions.

 

You might want to replace the thermostat? Mine was doing the same thing and that's what it was.

 

Check the coolant level in the reservior. check the electrical connection to the reservior also.

 

Sounds like it may have been an air pocket trapped in the system from when the water pump was replaced and it worked its way through...when it went by the sensor it flashed it with steam. Possible?

 

I have replaced the engine sensor twice ! Is there a sensor in the coolant tank ? should i get the cooland tank replaced so and if there is air stuck in the system does it work its own way out or do i need to do anything should i get it flushed out wit a coolant flush also

 

Unfortunately I cannot speak from experience with the A6, but typically there is a bleeder valve at the highest point of the system (near where the upper heater hose comes out of the block). You would need to open that bleeder while filling the system until coolant begins to flow out the hole on the top of the bleeder.

 

it may be the warning light for low coolant

 

Try replacing the Coolant Temp. Sensor...it's only like $20, and if you know it hasn't been done in a long time it's a cheap possible fix. The old black sensor's are known to go bad, so try getting a new updated one. If that doesn't work and you know it wasn't an air pocket you might need a new thermostat. If you had to replace the water pump, chances are your thermostat definitely needs to be replaced as well. But that's only if you haven't already done it with the timing belt...


LampyB.

ps. If there's not a pressure build-up in the coolant reservoir you're definitely still well off...just DONT LET YOUR CAR OVERHEAT or you stand a STRONG chance of blowing a head gasket!