Cylinder head removal problems

[Big Eck]

Hi all,

I’m in the process of removing the cylinder head bolts from my ‘95 Discovery after an overheat and blown head gasket. I have run into a problem - I cannot get 2 of the bolts loose, and I am perilously close to rounding the bolt heads on them.
I was using a 1/2 inch drive breaker bar with a 16 mm 12-point socket. I’m going to switch to a 5/8” 6-point socket tomorrow (will need to go buy it) as that is what I understand I am supposed to be doing after some research.

any other suggestions for breaking these bolts loose? Can I use an impact gun?

if I do end up rounding the bolt heads, any suggestions for how to proceed at that point?

Thanks in advance for all your advice.

Keith

 

[special ed]

Have a friend come help. Grab a prybar and your 5/8ths 6 point. use a breaker bar instead of a ratchet. Apply downward pressure with the prybar on the head of the breaker while removing it. This will prevent the socket from sliding up on the bolt head. The stretch bolts are soft so the heads can deform. also if your dealing with the end ones under the oil make sure the area is free from carbon buildup not letting the socket sit all the way down.

 

[Big Eck]

Thanks for the advice. @special ed. The 2 bolts that won’t come out are exactly the ones you mentioned - top row, both ends. I had wondered if the residual oil present where these bolts are, was also contributing to the slip. Will check for carbon buildup and will try again with the right socket and some downward pressure.

 

[Tugela]

Buy an impact socket. I had success using this combo:

• 5/8" impact socket
• 1/2" drive breaker bar
• breaker bar extension (I slid the jack handle over the end of the breaker bar)
• second set of hands holding the socket firmly on the bolt head
• (I also used an impact swivel to reach the bolts closest to the firewall)

Wear gloves. When the bolt cracks free it may send an uncomfortable jolt up your arms. If you round the heads, you may try a bolt extractor kit. Thankfully I haven't had to resort to this so I can't speak from experience how they work.

More head gasket replacement tips here, in case it's useful.

 

[p m]

Typically the socket+breaker bar doesn't clear the rearmost valve. I bought a 1.5" long 1/2" extension, but you may be okay with a deep 6-point 5/8" socket.
... and never use 12-point sockets on head bolts ...

 

[robertf]

remove the motor mount pucks. rear bolts become easy to get to

 

[Big Eck]

Thanks all for your help. I got the remaining bolts out last night! I bought some 6-point SAE impact sockets (both standard and swivel style) and that did the trick. The difference in contact on the bolt heads (6-point 5/8” vs. the 12-point 16mm socket I was using previously) was very noticeable, and the bolts came right out, even the slightly rounded ones. One thing I wish I had done slightly differently was buy the deep version of the impact sockets - I think that would have been the perfect size, along with a breaker bar. May still do that for the reinstall.

The heads are out now, and one of them has a slight warp to it, so I’m now tracking down a local machine shop to inspect and probably resurface them.

This has been a learning curve for sure - thanks for the advice along the way.

 

[boxster]

Thanks all for your help. I got the remaining bolts out last night! I bought some 6-point SAE impact sockets (both standard and swivel style) and that did the trick. The difference in contact on the bolt heads (6-point 5/8” vs. the 12-point 16mm socket I was using previously) was very noticeable, and the bolts came right out, even the slightly rounded ones. One thing I wish I had done slightly differently was buy the deep version of the impact sockets - I think that would have been the perfect size, along with a breaker bar. May still do that for the reinstall.

The heads are out now, and one of them has a slight warp to it, so I’m now tracking down a local machine shop to inspect and probably resurface them.

This has been a learning curve for sure - thanks for the advice along the way.

Make sure you use a good competent machine shop and surfacing the heads is part of the valve job.

 

[boxster]

Make sure you use a good competent machine shop and surfacing the heads is part of the valve job.

How many miles on your D1?

 

[Tugela]

The heads are out now, and one of them has a slight warp to it, so I’m now tracking down a local machine shop to inspect and probably resurface them.

This step is not optional. Unless you like doing head gasket replacements, because you'll be doing it again before long.

 

[kris812]

This step is not optional. Unless you like doing head gasket replacements, because you'll be doing it again before long.

I 100% agree.. the P/O had the head gaskets done on my Disco. When they leaked I pulled them off and one was bent like a banana. 6 passes to level it up.. Mind you a LR DEALER did the gaskets for the P/O!

 

[mlnnc]

... When the bolt cracks free it may send an uncomfortable jolt up your arms. ...

Yeah, and the sound can make you think you broke the bolt. Fun times!

I used a 5/8" impact swivel socket when I replaced the head gaskets on my truck 13 years ago.

 

[Dogbreath077]

Check the height of your heads. Because the valley pan is also the intake gasket, the heads can only be milled but so much. I do not have that spec handy. If you mill too much then the intake ports will not align with the gasket properly. Also, check for valve to piston clearance after milling.

 

[discostew]

Thanks all for your help. I got the remaining bolts out last night! I bought some 6-point SAE impact sockets (both standard and swivel style) and that did the trick. The difference in contact on the bolt heads (6-point 5/8” vs. the 12-point 16mm socket I was using previously) was very noticeable, and the bolts came right out, even the slightly rounded ones. One thing I wish I had done slightly differently was buy the deep version of the impact sockets - I think that would have been the perfect size, along with a breaker bar. May still do that for the reinstall.

The heads are out now, and one of them has a slight warp to it, so I’m now tracking down a local machine shop to inspect and probably resurface them.

This has been a learning curve for sure - thanks for the advice along the way.

I always kept a couple of shallow sockets for that, and the short extension. I would get the snap on guy to replace the sockets when they would start to fit a little loose.
I was doing 2 or 3 head gasket or stuck valves a week back in the day.

 

[special ed]

I always kept a couple of shallow sockets for that, and the short extension. I would get the snap on guy to replace the sockets when they would start to fit a little loose.
I was doing 2 or 3 head gasket or stuck valves a week back in the day.

I do the same thing, get the snap on guy to warant out the common sockets like 8mm 10mm 13 and 5/8ths.

Do you remember when they came into the dealerships and said add a bottle of this mystery stuff to the fuel tank on every oil change? They had us add a bottle of techroline and we went from 3-5 valve jobs a month to 1 every couple months. Then the 2003s started failing, would come into the get the first oil change and never make it back out.

 

[terryjm1]

When I google techroline, Chevron - Techron comes up. Is this what you guys used?

I have heard from some mechanics I have a lot of trust in that this is the only fuel treatment that really works, both in keeping the fuel system clean and lubricating the valves.

 

[special ed]

When I google techroline, Chevron - Techron comes up. Is this what you guys used?

I have heard from some mechanics I have a lot of trust in that this is the only fuel treatment that really works, both in keeping the fuel system clean and lubricating the valves.

Yep, Techron. They supplied the dealers with it to add when we changed the oil. We were having so many valve stick issues. They almost stopped in their tracks within a year.

 

[discostew]

I do the same thing, get the snap on guy to warant out the common sockets like 8mm 10mm 13 and 5/8ths.

Do you remember when they came into the dealerships and said add a bottle of this mystery stuff to the fuel tank on every oil change? They had us add a bottle of techroline and we went from 3-5 valve jobs a month to 1 every couple months. Then the 2003s started failing, would come into the get the first oil change and never make it back out.

Thats funny. I don't remember that. Did you work for Land Rover back in the day?

 

[discostew]

When I google techroline, Chevron - Techron comes up. Is this what you guys used?

I have heard from some mechanics I have a lot of trust in that this is the only fuel treatment that really works, both in keeping the fuel system clean and lubricating the valves.

I don't think thats the same stuff. GM has you put that stuff in fuel tanks. I've seen it do crazy shit. 3800s used to get an injector stick closed. If you tap on it it starts working again. That techron stuff would get in the injector and free it up. It puts a slippery and protective surface on everythin, like the fuel sender card.

 

[ezzzzzzz]

If you have the heads shaved you’ll need to confirm adequate lifter to rocker clearance. Crower lifters require.020-.060 clearance between the rocker arm and valve stem. I would surmise that any lifter also need said clearance. Adjustable or shorter pushrods might be called for.