head bolts should be changed as they are designed to stretch when you tighten them

 

Peugeot say that original (as in original Peugeot) bolts may be reused if they fall within spec, measured the bolts and they were fine so took their word for it. With hindsight I would have replaced them.
Bill.

 

I`ve always got new bolts with every head gasket job.
Peugeot used to,not sure if they still do?,supply a sachet of Molykote grease in the box with the head bolts.
Of course its important to have spotless and lubricated threads.But,if you over do it the head bolt can "hydraulic" in the block.

 

First of all, new bolts.

Most manufacturers state that their head bolts can be used twice but all of the rundown stations I've seen will loosen and then retry the entire tightening process if any bolt fails an angle check (or whatever) during the first tightening. Thus your two lives may have been used up before the engine even left the factory.

Then, what do they say about lubrication?

Production head bolts are supplied lubricated. Having not bought any (yet), I'd assume that service ones are also, as all other bolts I have bought (suspension, etc) are supplied in sealed packaging. Therefore they may not need further lubrication but I'd follow the prescribed service procedure. We use SAE 50 as a multi-purpose assembly oil, for example. If they don't specify a lubricant, then you shouldn't use one. What you can do, by oiling when you shouldn't, is significantly increase the amount of Clamp-Load you should be getting from the 20Nm meaning that some of the extra 240° is excessive. I'd be surprised if this was why you'd hit a wall at 140°, though, and I'm afraid it may be that you've discovered another issue. Run a longer bolt with the same pitch down the thread to make sure the female thread is clear and undamaged.

Cheers, Jim

 

I reuse headbolts on engines that have no history of issues NFUs for example even 2 litre diesels but i would use new bolts on the 8 valve engines as they are prone to oil leaks and need all the help they can get

 

Well guys, thanks for all the input.
Just to throw something else into the pot, its the last bolt (No 10) in the tightening sequence that was the problem, this is on the outer side of No 1 pot which is exactly where the gasket had breached into the water jacket, I suppose this could have been going on undetected for a long time and water contamination may have caused micro pitting in the thread and thus friction. Anyway its now fixed (I hope!) I backed out the offending bolt using the angle gauge to measure the point it became loose (155deg) cleaned out the thread again, finally washing it out with alcohol and air line. Lubricated a brand new bolt with moly and angle tightened 155 deg so then at the same point the last bolt stopped (20nm +140) turned it a further 90 deg which is just on the 'safe' side of the the 20nm +240 specified. Fingers crossed!
Bill