Golf IV Thermostat replacement

[AntiThesis]

Oh my soul.

My thermostat recently failed. I picked a new one up from a local place and fitted it. While checking whether things were working, I noticed it was leaking. Turns out the O-ring was shot. Excellent. Trundled off to the local again and grabbed an O-ring.

Even with this new O-ring, the system leaks. After looking at it, it turns out that the thread on the engine block that the thermostat housing mounts onto is stripped. Fantastic. Fortunately, the thread hole goes back about 15mm more than the original bolt so a slightly longer bolt has allowed me to secure the thermostat housing perfectly. Woohoo!

Except not. It still leaks somehow.

I'm sorry for the long post but has anyone else had anything like this with their MK IV? (non GTI)

[Jmac]

Replace the plastic housing mate, these things leak
Cheers
Jmac