I have a 2000 Disco II with 140K - A good 10y of service. As of the last year or two, it has developed coolant leaks. Some noticable on the back left rear of the block with the valley/intake weak point. Pulled the intake and tightened up on the intake mainfold bolts with a hand wrench, this put everything back in check. Minor maintenance with a pint a week to keep everything on the up and up. Pushing thru the snows here in the states over the past month, I feel I have poped a head gasket. Temperature shot straight to the red then came back to mid range and made it home. Topped the coolant of and bleed the system with the vent valve on the coolant hose. Going to work, the tempature shot again into the red so I stopped and cooled it off and noticed the coolant reservoir cap had sprung and blasted the engine compartment with coolant. Made it home and bought a new cap thinking time had degraded the o-ring seals and could not maintain pressure. Tried to go to work the next day and hit the red zone again, cooled and filled it to limp to work. Did not make it home - red zoned again so I towed it. Took it to a rover garage and they felt I was pulling air in the coolant system and air binding. They fully vented the system and treated it with K-Seal to tighten up the leaks. I drove to work and back (50 miles round) and 25 miles to the air port, everything appears to be fine - three days later I did not make it back home at mid night with another red zone / coolant throw up bit. I bought a Jeep Commander to cure my woes but the Disco is still in the garage. I was going to take a shot and just replace the head gaskets myself as I believed this was the problem in the first place. Under load engine pushing combustion gasses into the coolant system over pressurizing and blowing the cap. The Disco can be started and I can move it around. Exhaust is clean but I have a sweet smell of DexCool...Is this block worth saving as I have fed it a steady diet of synthetic oil over its life.

 

Have you every pulled your thermostat in all of this?

If it is the head gasket and you have another truck, I would try to fix it. Me personally, I couldn't let it go. Be aware that you may have dropped a liner in all of this, but I couldn't let it go on chance. It isn't worth much if you try to sell and if you fix it, you can give it to one of your kids.

 

No - Thermostat was not replaced or pulled at the garage. I bought one and I have a intake manifold gasket kit from Atlantic-British online shopping. Was gearing up to do the work myself but found myself time starved with family and work. The temperature comes up even and smooth when at idle and I let it run an hour - temperature dead center in the band. When driving the temperature stays dead center then rockets up I guess when the cap lifts and the pressure boundry is lost. Would the thermostat cause these symptoms? And your right I don't want to let it go for parts/scrap, my Disco has a wonderful interior with clean leather, minor dings external and when the beasty runs, quiet as it can home from the dealer new (and it is paid for!).

 

well after re-reading everything, I think you are looking at head gaskets. I would never suggest putting block sealers in because they only mask problems and you will have an even bigger problem when it goes.

Just a warning- when these things get hot, they drop liners easy. If a liner is dropped, you are done. It costs more to have a new one put in than it does to get a new short block. I would pull the heads and seriously look at it. Check the tops of all the liners before you start replacing the gaskets. It may even look fine and fail under load. A few people have replaced the gaskets only to find that a liner was toast. If you are really adventurous, buy a good used block and throw it in if you think this may be the case. If it was me though, I would at least try the gaskets.

 

Thanks for the help, I was able to trace down a engine article in a 1961-62 motor trend magazine for a buick/GM with a diesel buddy (his first car) and a good discussion, you can see the most likely problem in the block cut away pictures. The motor was originally made a 3.5L with sleeves cast into an aluminum block. The non-replaceable outer sleeve has circular ridges running the length like a ruffle potato chip. Does anyone have a picture of a dropped liner?

 

Compression checked all 8 cyl w/ 170-190 psi second check had a range of 180-190 psi. Pulled intake and heads this past month - Lessons learned for the 50ish crowd and removing these head bolts: 5/8 inch (non meteric and fits tight) impact socket, 1/2 drive craftsman breaker bar, 1/2 craftsman impact swivel socket for the funky angles on the rear bolts, 3 inch and 6 inch extensions when needed and 3 1/2 foot piece of pipe. Make sure, real sure to wipe head bolts dry and grease/oil free when removing these - got all mine off with mimimal trouble. Appears number 4 cylinder and head gasket showing indication of leakage. Inspected and never saw a tell tale sign of cylinder to coolant passage leak. Checked all cylinders and saw nothing noteworthy of a dropped cylinder.

Got the heads worked w/ new valve guide seals and skim cut to refresh surface. New water pump and a fresh set of hoses.

No signs of a dropped cylinder - appears to be just a head gasket problem.