over heating

my td 90 is over heating when at high speeds or going up a long hill. have changed the rad and has made it over heat less. could it be a failed thermostate?? and which way does the thermostate go in to the housing??

Does the top rad hose get hot when the engine is up to temp? i.e. is the hot water getting to the rad, if not then it could be the stat is jammed shut.

What engine do you have?

The stat unless its a non LR engine or something, is going to be top front, housing will be 2 or 3 bolts to remove and get at the stat, the wax mechanism sits in the bit you don't take off, so in a 2.5 its going to be wax mech down, in a 300its the wax mech into the housing so the top is still facing you. I would suggest you take the stat out, top it up with water and try it like that for a bit, it will take MUCH longer to come up to heat but if it doesn't overheat then its stat related.

It could also be an airlock - again engine details here would help - also once its got hot does it fall back down quickly enough and how hot is it getting?

water pump?
what engine (still the original TD?)

it is the standard turbo diesel. and when i come to a stop cool down quically, but when at high speed or if climing a hill it go to the very top of normal.

when you say it overheats does it actually boil over or just go up on the guage,,i had this very same issue with my old td i replaced rad,replaced water pump,replaced temp guage,replaced thermostat and still the same problem mine used to go to the end of the white section on the guage and i would panic and pull over and wait for it to cool down,then a friend of mine suggested lettin it run past the white setion but not quite into the red,when the needle got just past the white the thermostat would open and the engine would cool to the point of the needle sitting half way and then runnin up after a while,it could be that the point on the guage is the point where the thermostat reaches its operating temp,but if it actually boils over could be a crack in the head

The td I had in my 110 used to get wel hot when worked hard. I think they're just hot running engines. It would go up the guage on a long climb then come down again as soon as it got on the flat. Never boiled but it was a bit unnerving. You want to throw it out and put a tdi in anyway then you won't have to worry about it.

:crazy_driver: thats exactly what i have just dun..and my god!!!!!!!!!!!!!!!! what a different beast it is now where has all this sudden power come from i love it