Hi everybody I am running a 2008 58 plate Daf 105 510 which has only done 650,000km. It goes fantastically well until lately it has started to blow coolant out of the pressure cap down the small pipe on the side of the rad. There is no power loss on the engine and no overheating problems but I am forever topping it up with coolant.
Any advice greatly appreciated thanks 
My guess would be head gasket, I don’t know if these have wet liners but a cracked liner would be on my list to check as well, is the oil milky? I had one pop a liner but never lost any power, only blowing water out of the cap and mixing with oil.
Thanks for the reply brados but I check the oil everyday and it isn’t getting milky it’s very clean
I would suspect head gasket then unless these engines are prone to cracks between the valves in the head. Do you know anyone with a sniffer to test the coolant for gasses?
the MX engine in the XF105 does not have the same issue with the head gasket as the XE engine in the XF95
it is a completely different engine
that said, it could still be the head gasket
Check for excessive moisture in the air tanks, it could simply be the compressor head gasket which will over pressurize the cooling system. Listen for air bubbling through the header tank with the air built up and engine not running.
Try a new cap I seem to remember the same prob that’s all it was
Tarmac duck:
Try a new cap I seem to remember the same prob that’s all it was
definitely try a new cap first as ive changed a few about £40 from daf.
TOECUTTER:
Tarmac duck:
Try a new cap I seem to remember the same prob that’s all it wasdefinitely try a new cap first as ive changed a few about £40 from daf.
We have a 85 that was doing this ,turns out the driver was over tightening the cap and broke the seal on the cap,I think there’s a point that you turn the cap to and no further.
i
Hello i have a 2011 daf xf which is doing the same thing. Any help where to start checking.