Coolant Loss
 

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?

How long ago was 3k miles? Sounds like it needs to go back to the repair garage to me or do some head gasket tests. Compression test and the gas leak test.

It was 8 months ago and outside the 3 month warranty given.

I have done a gas test from the headder tank and thats got no fault / no exaust gasses. So this is why im leaning to the ERG cooler.

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.

I would still probably call them and see what they say. I would think you’ll get some goodwill depending what the fault is. Maybe ask them to just diagnose first then go from there? Difficult one, I love fixing things but it drives me crazy trying to fault find and having no luck.

Ok so a small update - im convinced its the EGR Cooler as when cold the headder tank bubbles like crazy but once warm and the EGR closes and the bubbles significantly reduce.

Also, the heating matrix is only blowing cold air at the moment and as the cooler is inline to this matrix i think its presurising the system and creating a blockage.

Im going to investigate tomorrow and strip down the EGR and see if I can find a fault with it - fingers crossed that this is the issue.

Im also going to chgeck the gearbox oil to see if there is water in there from the radiator.

Fingers crossed for an easy fix.

See my post describing this>
https://www.volvoforums.org.uk/showthread.php?t=318347

It was the EGR cooler leaking, and I was told on here that it is very rare almost unheard of for these to fail.
The new part is very expensive but you can get second hand cheap, however its such a fiddly job that you don't really want to be doing it twice.

Good luck.

So its bad news sadly - the EGR cooler appears under low pressure thast its not failed so it must be the cylinder head. Going to have to strip it down and get the head pressure tested, skimmed and the valvs reset ready for a re-install.

A sad day but she will live again I hope!

That’s appalling that it’s gone again in 8 months.