Head Bolts

[Merlin]

I am taking my heads off to (hopefully) fix a blown gasket (overheating/loosing vast amounts of water)
It has been mentioned that I must fit new head bolts, is this the norm.? & how necessary is it?
3.9 1990 petrol

Merlin

[clbarclay]

It depends on the type of bolts used, If the head is held on with 'stretch' bolts then they should be replaced. When I replaced the head gaskets on my 1987 3.5 v8 they wern't stretch bolts and used locking compound instead.

[Bowie]

I might be wrong, but the Rover V8s don't normally lose water when a head gasket has gone, you normally find oil under the plenum/carbs, as it forces it out from the oilways, out the side of the block.

ALSO... there are some sites which recommend, when doing the headbolts backup, and torqing them down, DON'T torque the lowest headbolts down as tight as the others -just do them up. If you do them tighter then you effectively lever the head on the middle row of bolts, lifting the upper most edge.....

You probably want to google the last part, to confirm (I can't find it atm) but that is what I have read pretty recently on the subject.

HTH,

Bowie.

[clbarclay]

The lower 4 bolts have a lower torque value than the other 10 anyway acording to the workshop manual, but yes they arn't realy necissery and were removed on the later 4.0 and 4.6 V8s.

[Merlin]

How do you recognise "Streatch" bolts compared to ordinary ones?

[Range Rover Blues]

I don't replace the head bolts on a V8 of that year.  One of the giveaways to stretch bolt is that you angle-torque them rather than use a torque-wrench (they also often have a thinner shank in the middle) becasue they are stretching as you tighten.  The TD5 ones can be re-used 5 times but most garages recomend no more than 3, the bolts should be stamped with a centre punch when re-used, otherwise how do you know?

If you are unsure buy new ones.

The outer set of bolts (4 of) can be used, left out complteley, inserted to keep the holes full, just don't tighten them up to their max torque setting, it was found that they distort the head which is why they were deleted.  LR head gaskets for the 14 bolt head no longer have the outer 4 holes in them anyway, irrespective of what engine they are for.

What ou will need to do it get the head checked/skimmed.

[Rossko]

Water loss due to head gasket failure is as common as muck on Rover V8s.  Quite often you won't see where the problem is even when its all in pieces! But the hint will be to look for the steamed-cleaned cylinder(s), usually an end one.

cheers, Ross K

[Range Rover Blues]

Unfortunatley the steam cleaned piston can also indicate porous block syndrome :o

[Merlin]

Thanks for the info.  will be back on the job tomorrow(Tues) as the "Bank Holiday taking the wife out" syndrome got in the way!!!!