V8 Head Gaskets

[ja_parker11]

An 18 year D1 1995 owner that is starting work on the head gaskets. I am posting to the D2 forum because it seems most of the D1's have been converted, parted out or scrapped.

D2's on the other hand seem to be entering the stage widespread gasket failure at around 125k miles and the consensus seems to be repair either by fire sale to a subsequent owner or the current owner.

The problem has been with me since the 70's and the blown gasket on my 1968 Dauntless V6 Buick supplied 231 ci in the Jeep CJ5. With the Disco and Google there is so much more info available on the diagnosis, cause and fix.

However, I am not finding much info on the success of the repairs. As most of the failures seem to be occurring around the 125k mark, what is the experience with the repaired engines? Are owners getting 50k, 75k miles? Or enough to sell it?

Would like to here some history?

Thanks,
John



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[mearstrae]

Yes, these are know for head gasket failures. The important thing is to be sure the repair is made correctly. The heads will need to be straightened, done by a good automotive machine shop. Sometimes they can heat the heads in an oven and force them back into square and level, sometimes they need to be machined, sometimes both. Many folks disagree with using ARP head studs for a Buick 215 (they are available for the Land Rover at a higher cost for fewer studs) instead of the use once and throw away Land Rover TTY bolts with the weird torque sequence. I've always had good luck using the studs on aluminum heads and also, (against all rules and recommendation) I use Permatex spray gasket sealer on "self-sealing" gaskets. I did this to my '70 Rover P-6 about 20 years ago and it hasn't failed since (these older engines use the steel shim gaskets). Others who have used this method have been lucky enough not to have had further failures. In some of the newer 4.6L engines (around 2003) the seemingly blow head gasket is actually a problem with cracked head bolt holes in the block, a treatment with industrial block sealant seems to solve the problem. This happened to a friend of mine (2003, D II, 4.6L) who had the head gaskets replaced only to find that the problem persisted. Block seal did the trick and he's been running it for over a year.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

[ja_parker11]

Thanks, that is good news. We have two projects going, the 95 D1 and a friend's 2003 D2. We have bought two rebuilt heads that have been leveled ready to go into the 4.6. On the teardown we have the intake manifold off and can see the head/block seam has drips of permatex. It appears someone has been here before us. This is a recently purchased d2. We started going after the valve cover gaskets but kept going because of a cracked expansion tank. Should have investigated a little more thoroughly. Heads are probably OK.

We have two sets of tty's and the composite gaskets. Now you have me second guessing the self sealing with Permatex!!! I have been a big fan of permatex aviators brush on for years on the Lycomings!!!!

We are both retired with the objective of having our kids push the rovers in the hole with us in 20 years without having to do another gasket change!!!!

Thanks, again
John

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[mearstrae]

A cracked expansion tank usually shows a head gasket blown into the cooling system and building up pressure. So, changing the head was necessary anyway. I use the blue spray on head gasket sealer, but any sealer should work. Back in the olden days when aluminum heads first came out we had problems with head gaskets giving out (heads warping), this was solved by using head studs and sealer. Back then we had to dig around to get the proper studs, nuts, and washers, now they come as an ARP kit. Permatex won't fix the cracked bolt holes, as it's an internal leak into the combustion chamber, by drawing coolant up past the head bolt thread cracks or dripping coolant into the valley pan. I can't for the life of remember the name of the block sealer CD something, a thick, black, smelly concoction. Not the crappy blue stuff usually found at the auto parts store.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S