Head bolts - which sealant?

[CJH]

The head bolt above my number 1 spark plug seems to be weeping a bit. I haven't been able to tell for sure till now, as my heater hose was leaking near there too, but now I've replaced that I'm reasonably sure the head bolt is still damp.

I was tempted just to try and nip it up a fraction, but then I saw this advice, so now I know that's not recommended.

The reason for this post is to ask what sort of sealant is used - is it something I can get at a local motor factors? Haynes quotes a VW sealant 'or equivalent' - what's 'equivalent'? I could also do with some advice on whether I should try and fix it or just leave it. I've read about all the problems of the studs snapping, and I don't want to risk that right now just to fix a really tiny leak. On the other hand, the engine was replaced about 10 years ago (Elite) so there's a chance the studs aren't going to be as rusty as a 30 year old engine. And also, being one of the studs on the outer edge of the torque pattern, it seems feasible to fix this one stud without twisting/warping the head.

What would you do if it was your engine?

[123-jn]

The yellow stuff that comes with a gasket set seems to be a sort of silicone based sealant so I guess any sort of gasket sealant along those lines would do. I've just rebuilt my engine and would suggest that for a slight weap I wouldn't bother. But if it becomes more than this you would have to risk undoing the nut after having drained some of the coolant so that you can re torque onto a dry head with fresh sealant. Oil the threads before retightening (don't get any on the sealing surface.) retorq to whatever Haynes suggests. Quite how this would effect the seal at the top of the combustion chamber I don't know but hopefully it would be ok.

[itchyfeet]

The yellow sealant you get with the elring gasket set has no markings
Id say the black sealant you also get for the water jacket and case is thicker than the yellow so maybe its designed to be used with a very small gap

Anyway not seen it for sale so id use the black which is Dirko-s avalable on ebay
There is also dirko ht which is red and rated to the same temperature so not sure what the difference is as I have not seen it

As said leave it if its just damp wait until its worse

Or try placing some dirco around the nut without un doing it once you have cleaned and dried it

[CJH]

Thanks both - I'll keep an eye on it for a while then. The heater hose leak was creating a fine mist of coolant which had coated everything in that area. And of course, it only happened when the engine was warm and the water was under pressure, so naturally the heat of the engine bay was enough to have dried that mist off whenever I remembered to look. But there does appear to be a crystalline coating just below the head bolt. I suppose the good news is that that means the leak is very slight - if it was a faster leak the water would likely wash away the crystalline coating. I'll give it a good clean and then monitor it.

[colinthefox]

I've got plenty of the correct stuff left over from a recent engine rebuild.

If you still need it, PM me your address and I'll bung it in the post.

Not much call for it on diesels!

[CJH]

That's very kind of you Colin - I've given that whole area a good clean up today and I'm going to keep an eye on it for a while. If I decide to try and fix it I'll definitely get back to you.