Coolant Flange on Side - Studs or Bolts or both

[mk28vpb91]

Just saved my 1991 8v from MoT failure as it couldn't bring myself around to getting rid of it. So as I am obviously too attached to it I thought that better put a little more effort into keeping it going and reliable. One problem that I've put up with for ages is a slight coolant leak at the side of the head (plastic flange). As the heater isn't working well, the front flange is leaking (last changed ~6 years ago) and the metal pipe looks really dodgy I thought I would do a minor overhaul while the coolant is drained.

Can someone tell me what type of fastener holds the plastic flange on at the side of the head? They look like studs but the thread protruding through the nut is really crusty and I don't think that a nut would turn well on it. I am worried that I'll either break a stud off in the head or make the threads unuseable and then break the stud off in the process of repairing it (no place to keep car off road for long). The parts catalogue for the cylinder head shows something called a double stud near the location, so should they come out like bolts?

[mk28vpb91]

Just case anyone has the same question in the future, here's the answer (this is a photo of a new stud/bolt):

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Turns out, after failing to resist the urge to leave them alone, that the bolts with a stud attached detorqued without any problems at all. Haven't taken the flange off yet, but fully expecting to have to fill a few pits with epoxy to get a nice seal.

Incidentally Heritage in Bristol (VW dealers) couldn't supply the factory spec Front Flange (with the sensors) as it is obsolete. Stuck with repro from now on then.

[MBChB]

I changed the flange on my 16 valver a few months ago, and found that I got a good seal when using an original green O ring from the dealers. The flange itself I got from ECP, but for some strange reason they didn't carry the matching O ring. I wouldn't mess about with sealant if you can avoid it - the previous owner on mine had used sealant that I then had to clean off the block to get a nice seal with the proper O ring. Don't over-tighten the nuts, BTW

[dadrathers]

The stud is actully a bolt with additional thread on top to attach anotherr nut to it to hold the metal coolant pipe - so don't try and separate the two?? I had to use sealant as the face of the head was sufficiently pitted tht I didn't dare try just thE o-ring. in Any event, using a good quality sealant (and the o-ring) is belt and braces in my book not bodging.

[ajmk3]

Just a quick question about the coolant flange on the 16v, how did you access the flange, there's 3 nuts, ones rounded and I can't get access to the top nut? Thanks