C6owners :: Forums :: C6 Support :: Super Sticky

C6 2007 2.7 engine overheating

Home   Forum Rules    Forum Help  Conversion Tools
Please Register to enjoy additional Member Benefits
Top Thanked Forum Posts: Today | Week | Month | Year | All time | Most Thanks Given: To member | By user
Author Post
Wed Aug 24 2016, 04:14pm
Joined: Aug 24 2016
Member No: #2762
Location: Belgrade
Hello too everyone,

I have C6 2.7 YOM 2007 and I have problem with overheating, I can`t find where is leakage, we made test with pressure and there is no pressure loss but after 100-200 km I have to add 0.5l sometime 1.5L. Today I drive it on highway 160kmh-170kmh and when I stop temperature rised and after one minute gone back to normal, after that I drive 140-150 and it was normal.
There is no signe of water in oil, temperature of oil is normal
There is no oil in water also
Does anyone have some advice or suggestion how to handle this
Best regards,

Wed Aug 24 2016, 05:57pm
Joined: Sep 10 2013
Member No: #1429
Location: Glasgow
Hi Jovangt,

1-1.5L in 100km is a big loss so it is either going in the engine or out to atmosphere.

If it was going into the engine you would have lots of Mayo and the oil dip stick would be telling you it was overfilled. So rule that out.

When you pressure tested I guess you used an old cap and pressurised at the expansion bottle. Do you know for sure that the cap you are using when running is not leaking to atmosphere? Just to rule it out I would put a new pressure cap on.

Then I would run the car with the undertray off and when hot get it on a lift and leave it running. If you can't see any dripping then the water must be going into the V in the engine. Connections around the thermostat tank would then be suspect. But eventually that will overflow too.

I guess you have checked the famous steel water pipe to the car heater under the lhs front suspension? That should be obvious if leaking although it might not show up on a pressure test.

Good luck with it.

All the best, Frank

Jump:     Back to top

User Colour Key:
Head Administrator, Administrator, C6 owner, Technical Expert, C6 Premier Discount Club