Hi, I have a 2003 motorhome based on a Fiat 2.8td tag axel. Last week I noticed the cab heater had gone cold whilst driving it. Engine temp remained normal on the guage, very shortly afterwards it lost power ending up with me pulling into hard shoulder. Turned out to be split radiator (Vehicle recovered) Taken to garage and had new radiator fitted, cooling system refilled etc. Brought home from garage noticed heater still not working properly (Suspect airlock) back to garage vaccum presurised coolant system to draw air out, flushed through heater core / matrix to make sure no air lock. Still heater not working. Also when running quite a bit of bubbling in expansion tank (Thinking Head Gasket!) garage did a chemical test on expansion tank for exhaust emmissions, but came up clean (still blue liquid, not yellow). No whiite smoke from exhaust or anything else to suggest head gasket problems other than bubbles in coolant expansion tank / cooling system.


Took the van for a 30 min test run driving normally max 3k revs. Engine temp normal, no heater except slightly wamer as engine revs got to arround 2.5k. No loss of power or anything else on the run. Heater had no heat at all towards end of run (Suspected coolant loss again) got home and sure enough no coolant in expansion tank. Topped it up about 3 litres to get it back to normal level. Ran the engine and got the end of the pressure release pipe on the top of the expansion tank cap and it was blowing coolant out (Enough to expain the 3 litre loss). Obviously enough gas / air getting into system to exceed the pressure release valve on the expansion tank cap. Any suggestions?


Oil clean - not creamy
Chem Test for exhaust gas in expansion tank negative
No white smoke
Temp building and running at normal levels on dash guage
But heater not working, losing alot of coolant, presure enough to release expansion tank safety valve and blow the coolant, definitely gas of some sort getting into cooling system.

Any Ideas / help greatly appreciated.

Hi at normal temp are the two pipes that connect to matrix on bulk head cold warm or hot , are the top and bottom hose to radiator cold warm hot ,1 idea could the impeller off water pump be snapped off so coolant poor circulation ?you should get an idea by feeling coolant pipes

Ok thanks, will check tomorrow. Could this cause the Gas / Air in the coolant system?

No but if coolant not circulating the system going to over pressurise losing water out cap and no heat to matrix you say engine already had sniff test and passed are the coolant pipes to matrix hot?

If you have bubbles appearing in the coolant/expansion bottle, it is very likely a blown head gasket as a result of water pump failure...generally.
If water is being lost from the bottle whilst at idle and the engine is cold, then I would be satisfied that the head gasket is blown.
Try this. Turn the engine on from cold and look for 'air' bubbles in the tank. Switch off the engine and release the plastic cap very slowly and if you hear 'air' escaping, then the head gasket is gone.
From there, save up your pennies because you are going to need every penny you can find.
There are several things that can go wrong to cause a blown head gasket, but the result and the cost is no different.