Help with thermostat

[gtid4z]

Hi all im new to the site and was after a bit of help,

I have a mk3 gti 8v, had to change the thermostat, my bro stripped it and I put it back together and it’s leaking,
Problem being he forgot where the oring seal went, does it go between the thermostat and the block or between the thermostat and the plastic housing?

[thai-wronghorse]

The o ring should be between the thermostat and block iirc.

[gtid4z]

Thanks for that mate,
That was where I put it so most likely to be the plastic housing iv ordered a new one from VW.

[Rmachines]

Plastic housing    Yea.....  sounds about right 

[Dan_GTi8v]

on mine the o ring goes on top of the thermostat against the plastic housing. This is a 1.8t but I dont imagine the design is any different.

[Bandit127]

(Sorry for the necropost but posting this in case this thread is picked up by someone doing a search).

Did mine this weekend (8V GTI) and the o-ring was definitely between the thermostat and the housing, not thermostat and block as was stated earlier.

[itavaltalainen]

Can only agree with Bandit, done a thermostat on my 2.0 once separately, another time changed the water pump.
You first put in the thermostat, then o-ring, then put the housing on.

[thai-wronghorse]

Yeah that sounds right.

[mrsaunders]

Maybe Thai was thinking waterpump to block at the time?

[thai-wronghorse]

I think I must have been.  :embarassed: