My friend recently bought a 1997(C4) A6 with 2.6 ABC engine. Shortly after that he discovered that heater is leaking and not heating. I have changed heater matrix for him so it is not leaking any more. However it is still not heating and engine is overheating. All pipes coming out of engine are cold. Temperature gauge shows 90C, and antifreeze is coming out of expansion tank cup because of too high pressure. I guess original heater matrix went because of too much pressure in cooling system. It looks like there is no antifreeze circulation at all, it is boiling in heads and cold everywhere else. I mean if it was stuck thermostat water should still be going to heater and heatershould be still heating. It is like pump is not working at all. But I dont understand how can it be not working. If it would be stuck belt would be slipping and I would hear it sqeeking. Or it should have all fins broken off or a shaft snapped . Or could it be blown head gasket??? By the way I have removed top pipe on heater matrix and checked that there is antifreeze in heater matrix. So it rules out air buble in heater matrix. Anyone knows where thermostat is located in theese V6. Any advice will be appreciated.

 

Should have mentioned that there are no fault codes.

 

I think its in the same place as the 2.8 and 2.7 which is just to the passenger side of the waterpump. Usually if your going to go thru the trouble of removing the timing belt to do one you just replace both.

 

http://12v.org/engine/index.php?sect...&view=cool
this should help, impretty sure the 2.6 ABC was built on the same design as the 2.8 V6 12v here. just to let you know on this engine it is a real PITA to replace the thermostat since it is located in a housing behind the timing belt.

 

Ok So today I was starting to take covers of the engine and have a closer look. What I discovered was that whoever changed timing belt have done a poor job. Timing belt was totally loose and I could rotate water pump by hand with timing belt standing still. So obviously when engine was turning water pump remained still or turned very slowly. Therefor it have overheated got too much pressure and blown heater matrix. Also one of the camshafts have jumped one tooth. Unfortunatly head gasket has blown as well due yo overheat, looks like cylinder 2 is leaking cylinder to coolant. I recommended friend to change both head gasket set plus timing belt including water pump and thermostat but he don't want to spend so much money. Has anyone used stuff like Steel Seal(www.steelseal.com )or K-Seal ( http://www.k-seal.co.uk/k-seal.html)to repair head gasket. I am looking very sceptical at this but my friend would like to have a go and if that does not help than sell car on e-bay for spares.

 

If the belt is loose, i would replace the tensioner assembly if it is an automatic adjusting type. If those just poor it in gimmics actually worked id be out of a job. Sometimes those things will do more harm then good by plugging passages in the cooling system.

 

well one way or another fix the belt issue (obvious) as for the head gasket stuff its good but not sure about the long term, on my old honda a week before i sold it i blew the head gasket and after putting in teh head gaskt seal **** it felt better and wasent smoking or loosing coolant.