Overheating

[clarence]

T25 Westy 1.9 water cooled LPG,
New water pump,thermostat & water pipes to radiator,all hoses checked pressure builds up as per normal,Then boom the van still overheats and blows a cloud of steam as a hose joint gives,I’m now really peed off as the garage keep fixing the problem,I drove 80miles perfect,then 240miles perfect then started a 20 miles journey and overheats again
Now desperate for help !

[CJH]

I'm sorry to say that this may not be 'overheating'. It may be a leaking compression seal at the top of one of the piston barrels. The symptoms are confusingly similar at first (ask me how I know). A leaking compression seal allows combustion gasses to get into the cooling system. So the cooling system pressurises, apparently normally, but it's not necessarily down to expanding coolant but rather due to combustion gasses entering under pressure.

The tell-tale symptoms are:
1) If your cooling system is properly sealed, then it will stay pressurised even when the coolant has cooled down. So with a stone-cold engine, remove the cap from the header tank - if you can hear escaping gasses that's the first clue.
2) The level in your header tank drops as the combustion gasses displace coolant into the overflow tank. Eventually, so much fluid is displaced into the overflow tank that it gets blown out of the top of the overflow tank.

When the problem first develops, it may be that you don't get any gasses in the coolant if you just drive around under a light throttle, and you only have a problem if you drive hard. Eventually though the leaky seal gets worse and you have the problem all the time.

My engine started doing this, and it's now on an engine stand waiting to be stripped and rebuilt.

[CJH]

Here's a good description of the problem: http://forum.club8090.co.uk/viewtopic.p ... 5#p8167672" onclick="window.open(this.href);return false;