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4.6 V8 Stuck Head Bolt. Suggestions Please.


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Hi All,

This is in my P38 4.6 Range Rover but have put in International forum in the hope of more views as it's not Range Rover Specific.

Trying to remove the LH cylinder head today and cannot shift one of the rear bolts. It's the one right at the back inboard side.

I could not shift it at all and ended up using a 5 foot breaker bar. Despite using a single hex socket it has still rounded all the corners off the bolt head.

Due to the position I cannot get a drill in to drill the head off the bolt as the bulkhead bulge prevents me getting anything in.

So before I admit defeat and pull the engine out (really don't want to do this) and get it on the engine stand so I have more access, can anyone suggest a method to remove it?



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If it will not move with a five foot bar, I suspect that the bolt might have been put in with bearing lock because of a stripped thread by a PO. I have probably stripped and rebuilt at least 50 Rover V8s, and I cannot recall any bolts failing to come out, except for the water pump and front cover ones.

Sadly, I fear you are going to have to remove the engine, and carefully drill the head of the bolt off, remove the head, and apply a lot of heat to the remaining bolt shaft, which hopefully will then come out.

Dont know if the thread in the block will survive the experience :( 

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Thanks for the suggestions.

Simon, I will try to hammer on smaller socket/extractor tomorrow, didn't try today because the weather was turning. Also I thought it was better not to try at that point due to the mood I was in by then. Don't have much hope on either gripping as it wasn't moving with a 5 foot breaker, but will give it a try.

Ed, pretty sure there is insufficient room to weld a larger nut on. Apart from the restricted access the bolt head is in a narrow well between the wall at the end of the head and an intake passage, but again will have a good look at that tomorrow.

But I suspect Smallfry will turn out to be right and a PO has bodged it. I've also built a few V8s and had the heads off several more. Never come across a head bolt anything like this. If it was done by the same person who did some of the bodgetastic electrical repairs I've already sorted I wouldn't put anything past them!



Edited by MikeAK
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That sounds sketchy... definitely sounds like engine out time. Or maybe just remove the engine mounts so you can drop the engine down a bit and maybe have room to drill out the bolt then?

Hopefully there's enough meat left in the block to helicoil it after you get the bodged bolt out. Or thread the top of it and call it a stud :ph34r:

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Have you tried a bit of percussion on the bolt head, perhaps a blunt centre punch on the bolt head ?

Have you tried cracking tighter ? It sometimes helps to crack locking and sealing preparations.

I wouldn't be hopeful but good luck with it.


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I'd vote for hitting the head to try to break any corrosion or goop inside and then either hammer a sacrificial 12-point socket on or weld a nut on.

There's mobile services that use a special rig to sort of vibrate them loose (D3 glow plugs are terrible for snapping off) but ultimately I strongly suspect the ultimate answer is to pull the block - you'll have easier access to help you work, and I suspect a machine shop visit may be in your future to get it drilled out & helicoiled.

I used Banda Engineering in Portsmouth when I had an inlet manifold bolt snap on mine, didn't have to strip the engine and they only charged £40-£50 ish all in.

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The Head is off!!

Thanks to everyone for the suggestions. Applied heat and hammered the bolt head with air chisel with blunt bit then hammered on 12 point socket followed by bolt extractor. Both just rounded off it off more. It really didn't want to move.

Elbbeko's idea of removing engine mounts to get more clearance got me in there. Still not enough room to get a drill in, but enough to get a small pistol grip windy drill in. Max drill windy would take is 6mm so drilled down centre of head with that, then started opening it out with a die grinder bit. Only took about 2 hours!

When I had ground enough away heard/felt the head crack off the bolt, weird thing is although the head was now free to lift of the bolt, the bolt head was still stuck to the cylinder head. I had to knock it off with a chisel. The bolt unscrewed with fingers once the head was off. No damage to cylinder head apart from a small nick from the die grinder on the edge of bolt hole. The bolt looks new, no corrosion and no locking agent that I can see. Complete mystery to as to what has happened here.

All the other bolts were extremely tight, used a 3 foot breaker bar (didn't use the 5 foot again because I didn't want to round any more off). I have bruises on my chest from bracing against the slam panel whilst pulling with both hands. Only just managed to move them, and I'm not a little lad.

I will post what I found in the RR forum with more requests for advice later.

Thanks again





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Yes Ed was definitely Righty tighty, lefty loosey 😄

Elbekko as soon as the bolts "cracked" they were easy to remove using fingers and look to be in good condition, the block threads also look perfect.

It's as though the bolt head flanges were stuck to the head (the one I drilled/ground off definitely was). Maybe someone in the past used what they thought was lubricant under the bolt heads? It's a mystery.

Fridgefreezer yes I've already been looking at those and will use them if I end up doing any sort of rebuild.

Thanks everyone.

Iv'e started a new thread in the RR forum now the head is off 


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