Hi All
Okay I managed it and took a few photos in case anyone else is thinking of doing this.
The top cover is just a push fit held by rubber grommets. Access is easier if you pull this off first
I didn't need to removed the fabric hose as it lifts without damaging it easily enough to undo the two bolts that retain the thermostat housing.
I didn't think i'd need t remove the hose but it did make it easier for getting to grips with the thermostat housing. I just folded it out of the way.
The thermostat housing will fell like its stuck in there and its never going to come out. Persevere it does. It may well be better to rod this with a warm engine.
The thermostat comes with two seals. One is rounded and the other is square. Its fairly obvious which is which is you look when teh housing comes off. The rounded one goes over the cover and sits in the grove near the back of the housing. teh square one fits between the thermostat and the housing and the thermostat pushes it down when fitted.
I syphoned out the coolant from the header tank. This filled a 2 litre bottle. but I lost zero coolant when changing the thermostat after doing this.
My trouble wasn't so much my thermostat, more that it had been incorrectly fitted and when I removed the housing it was still sitting in teh head! Teh reason for this is the thermostat has two lugs and is offset and actually clips into the housing. There are two ridges and one lug fits in then you clip the other side in and it neatly pinches up the square rubber gasket. This will be obvious when you do it as it only goes in this way.
I'm sure there is abetter lubricant to aid refitting but i didnt have one and just spat on the seals!
A quick wiggle and it was back in.
Despite some posts saying over tightening will crack teh housing I can ssure you it wont as it has metal shims in there to stop this. The two seals are what keeps iyt water tight so you dont need to tighten it much anyway. I didnthave the torque settings but am familiar with tightening bolts into aloy anyway.
Looking at my two thermostats you can see the replacement has a metal insert so maybe an upgrade? Its made by Wahler (as was the one I removed?). I got it from GSF and it cost £15.45 + VAT. GSF number 176NE0190
It now warms up much quicker and sits at a stable one bar above the half way mark. I assume that is right?
Anyway, easy enough job apart from wresting the damn housing out of the head. Hope it helps someone.
Did you have any issues with airlock?
