[Clan]

Originally Posted by NMB

Hi everyone,

Brains required please as i've been scratching my head and I think that I have solved the issue with my Volvo XC90 RDesign Nav 200 BHP on 100,545 miles. I need some thoughts from you please!

So, to start with,I bought the car on 97k miles with a blown head gasket. I paid a Garage to sort the issue, which they did, and the head was skimmed, pressure tested and re-fitted and i've had 3k trouble free miles with the engine.

However, recently, its started to drink coolant and the resivour behaves in a weird way. On high revs water is sucked our of the headder tank and then back on idle the water seems to return. However, water is missing and its progressivly getting worse and it needs topping up. I regulary get "Low Coolant" warning and have to stop.

This is where I have been getting also confused as there is some presurisation in the water system.

Now this leads me to think that the Head Gasket has failed again..... BUT, the engine sounds just fine, not lumpy at all and runs smoothly. There is no loss of performance and its got no symptoms of a blown head gasket at all. There is no contimanation in the coolant or the oil.... The Gearbox oil is ok also...

By chance, I did a live data read of the engine of randomly selected components and I noticed that the EGR Valve was opperation out of parameter 65% low idle (hot) and whern the revs come up it goes to low teens.

No im now thinking, could the EGR Valve be causing my issue of coolant loss?

Thoughts?

Did they check the top of the block for flatness whilst the head was off ? It is just as important as the head being flat... If the engine got hot enough to warp the head it is possible the block is warped too.