Sheared bolt on thermostat housing

[maxsheba]

I have a 1992 Mk 3 2.5 diesel 100 pop transit. Removing 2 bolts from thermostat housing I sheared one bolt head off. How do I get the bolt out and is sealing liquid as good as a gasket. Thanks

[GBBiker]

You will need a stud extractor and a tap wrench (as in drill & tap as opposed to a plumbing tap wrench). Drill a hole about 8mm deep down the centre of the bolt, approx half the diameter of the bolt itself (iirc, they are M6 so you want about a 3.5mm drill). Stud extractors usually come in sets of four or five different sizes and have L/H threads. As you turn the wrench anti-clockwise, the extractor will effectively screw itself into the hole you have just drilled. Once it bottoms out, it will start to remove the bolt.

Have some patience as the bolt may well be corroded to the block. You may also want to try a squirt of WD 40 on the bolt 10 minutes before you try extracting it.

Oh, liquid gasket will be fine - just use the high temperature one.

[darkbluevanman]

If there's some old bolt to play with, not snapped flush, you've a better chance.... either need heat or freezing, a good tap with a hammer and some quality grips...

As for the liquid goo, as GB says high temp silicone is best, but do not assemble straight away, let the silicone 'skin' a little before fitting