type 25 overheating

[rjshare]

ok then, all you t25 geniuses, heres a problem for you (well, for me actually!)

i have a t25 1900 petrol watercooled DG engine, which had justbeen installed when i bought the van, and has never run correctly - hence getting the van on the cheap!!

when the engine runs at idle, or even at a fast tick over, everything apparently works as it should, ie radiator warms up, all hoses get hot etc, even the fan works correctly when it gets hot, but as soon as i start driving anywhere with it, the temperature guage goes through the roof and it boils over. all of the hoses etc seem to be unblocked and watertight, and there is no water coming out of the exhaust or getting into the oil.

the only possible cause that i can see is something to do with the lubrification as the oil light flashes permanently, but i believe that this is down to a faulty pressure switch and nothing else, although i do have one ordered and on its way so i will know about that for sure in the next few days.

does anyone have any ideas as to what could be the problem before i end up junking the engine and buying a diesel out of a golf or something??? the cylinder head joints seem to be watertight, and i don't want to replace them only to find out the problem is caused by something else!

[quickie]

I also have had a T25 for about a year. It also overheats randomly,(?) either when just completing a 200 mile 70mph blast up the motorway and then boiling in the vanfest car park, or 100 yards away from my house when the radiator is still stone cold.
To date I have
1) changed the thermostat (including running without one)
2) changed the waterpump
3) changed most of the hoses
4) had the radiator pressure tested and flushed
5) had the head gasket checked -no gases in the expansion tank or emulsion in the oil filler
Most 'experts' (though not all) think that there is a gas lock somewhere
in the system
The advice I have been given includes
1) jacking the van up to 45 degrees
2) changing the top hose to a renault one, with a bleeder screw in it
3) drilling the top of the thermostat housing,tapping a thread and fitting a bleed screw
4) increasing the amount of antifreeze in the system (yes,honest!)
5) put a teaspoon of bicarb in the system (wierd or what?)
6) 'I never do anything, they always bleed themselves'
7) Set fire to it
SO YOU THINK THAT YOU HAVE PROBLEMS!
Did you have any luck in sorting out your overheating, or did you resort to advice No 7

[GTImad]

I know someone who has had occasional overheating problems, resulting in burst water pipes on 2 occasions.
It turned out to be the expansion tank cap
A new cap cured the problem.

[tigger and pooh]

Just sounds like airlock,with air in the system the water will not circulate properly if at all?