audi a6 cooling problems

[wright2000]

:1zhelp: I have just bought an audi a6 1.9tdi. I drove 110miles back to my house with no problems, temp gauge stayed at 90. After doing the school run for a couple of days , the temp warning light came on. I checked the level and it was low. Refilled and the following day the level was low again. Now the car runs very hot when driving fast and i can see water drops from under the header tank relief valve. The bottom hose feels cold compared to the top hose which is very hot. The header tank also feels cold. I have removed the water pump(plastic type ) and fould it ok ( all new parts) I have fitted a new thermostat before removing water pump but made no change. There is no smoke from exhaust and no mis firers. Theres no sign of head gasket gone but does anyone know if this could still be a possibility?? Does anyone know if the small hose that returns to the header tank should have coolent flowing from it when the engine is running, because mine does not ANY SUGGESTIONS PLEASE !!!!!:confused: :confused:

[Peter D]

If you top the water up and allow it to heat up with the cap OFF now it is at 90 fit the cap and hold the engine at 2,500 prm for 1 minute. Now check the hoses if they have become pressurised then I would start to suspect a leaking HG into a water way. Go to an indi and have the gasses from the header tank sniffed for combustion gasses. What coule is the coolant. Regards Peter

[wright2000]

If you top the water up and allow it to heat up with the cap OFF now it is at 90 fit the cap and hold the engine at 2,500 prm for 1 minute. Now check the hoses if they have become pressurised then I would start to suspect a leaking HG into a water way. Go to an indi and have the gasses from the header tank sniffed for combustion gasses. What coule is the coolant. Regards Peter
hi, thanks for reply.
before i draine it the coolent was clear pink colour no sign of oil. what do you think about the small return hose to the header tank, theres no flow there.

[a8 tech]

Sounds like the plastic impellor has dislodged from the knurled surface of the water pump.Remove the smaller pipe at the header tank and check for return flow from the water pump.

[wright2000]

Sounds like the plastic impellor has dislodged from the knurled surface of the water pump.Remove the smaller pipe at the header tank and check for return flow from the water pump.
i took the pump to my local audi dealer to check.they said it was a new one.do you know if my car has 2 thermostats or just the normal 1.this is my first time working on an audi.should there be water flow to the headertank in small return hose.no flow from mine.a ford or vauxhall would do?THANKS

[a8 tech]

one only and yes at increased rpm you should see returning coolant.I would instal some clear pipe to check the return flow and make sure the thermostate is opening,it will take a good while to warm up with the auxilary fan spinning .Run at 2000 rpm for 20 mins or road test to normal temp then check the lower hose by hand for temp and check the return pipe for flow.If ok consider combustion leak test

[wright2000]

thanks i will give it a try

[wright2000]

one only and yes at increased rpm you should see returning coolant.I would instal some clear pipe to check the return flow and make sure the thermostate is opening,it will take a good while to warm up with the auxilary fan spinning .Run at 2000 rpm for 20 mins or road test to normal temp then check the lower hose by hand for temp and check the return pipe for flow.If ok consider combustion leak test
just one more thing, when i removed the cam belt cover i noticed the three bolts on the cam shaft spocket gear were completely to one side of the adjustment and could clearly see where original bolts had been. would this make the engine run hotter?
thanks

[Peter D]

Yes I had considered cam timimg as a possible cause due to the unknown history so I would get that checked out. Regards Peter

[wright2000]

Yes I had considered cam timimg as a possible cause due to the unknown history so I would get that checked out. Regards Peter
thanks

[Lex Luthor]

just one more thing, when i removed the cam belt cover i noticed the three bolts on the cam shaft spocket gear were completely to one side of the adjustment and could clearly see where original bolts had been. would this make the engine run hotter?
thanks

If the bolts are tight its probably ok.
When the cambelt was changed the cam pulley ended up in a different position. This is quite normal.