Club 80-90 Forums

is it physically possible to put the stat in upside down ?

Dunno ... but it would explain it not opening

radiator has been flushed out and hose pipe connected tight and water coming out other pipe.
stat wont go in upside down plus the rubber seal sits on the stat and seals the top of the thermo housing.

So you are sure that the radiator is not blocked
you have checked the stat in a pan of hot water and it opens
The only thing left for me is a blocked return pipe from the rad to the stat.

the pipe running to the stat on the left side is hot the pipe to the right of the pipe is cold.
going to see if local vw dealer has a stat

big fat pipe down side of engine will be hot it's not affected by the stat it's part of the engine's own circulation system, ie always hot, and the small pipe that comes into it 4" after the stat housing is the heater return which you know is working so there is circulation to and fro the heater matrix, just no proper flow from the rad and that flow is controlled by the thermostat.
Try taking the stat out and see what happens, it should all get warm but run at below proper working temp, if that doesn't work there's a blockage/airlock/weirdness

ok took thermostat out and everything warmed up. complete radiator warm top to bottom.
took for a spin and 20 mins into driving around town and onto dual carriage way. the engine went off like a kettle.
cooled it down . topped up again bled rad. 10 mins later off like a kettle.
put thermo back in just to try. rad warm at bottom cold at top.
temp sender then showing half but engine still over heating.
revved engine to 2500 bled rad and still over heating.
bit lost on this one

definitely a blockage in the pipework and/or engine.

or the water pump is not pumping coolant around like it should

when im bleeding the rad the water is shooting out . thats with adding cold water to the tank in the engine bay.
if the pump wasnt working it wouldnt be flowing out the bleed valve would it ?
tomorrow im going to be stripping alot of the pipes and take the water pump off.
what a night mare

Yes the pump sounds ok then, but pumps can lose vanes and there's slipping,

I mean the return pipe, from the rad to the housing.

Hell we're just tossing relevant stuff in the mix here, you're the one whos next to the problem.
hang in there pal at least your not on your own with this

when you say went off like a kettle do you mean that boiling water and steam came out of the top of the top up tank ?

Aidan wrote:when you say went off like a kettle do you mean that boiling water and steam came out of the top of the top up tank ?

oh yes the expansion tank was whislting with steam and bubbling away like a kettle going off. with and without the stat it overheated

need to get a sniff test done, I don't think this is a stat problem

Hmmmm.. a sniff test will certainly confirm your suspicions Aidan

sniff as in exhaust fumes coming from water?