We bought ours at Sears.

2003 Discovery 124K with high miles service complete.

 

Disco Mike and Rovin4life,
I have a coolant leak coming from rear of engine where I cant see clearly, but seemed to be coming from rear of a cylinder head or valley pan. It overheated close to home, Temp gauge shot up to upper limit then setted back down rapidly. Got it home and checked coolant which was low, topped it up and started it. Saw coolant leak from same unseen source and engine seemed to run with occasional misfire. Shut engine down and here we are.
I have upper manifold removed at this point and am stuck until I find socket for valve cover bolts that will reach. I Have secondary air units removed other than bosses in heads. Are they what you recommend an air chisel to remove?
Engine cant be warmed up at this point so will have to attempt exhaust manifold removal cold. Looking at rear of valley pan area now, I can see slight evidence of coolant leak,( residue near valley pan gasket ) but still cant see clearly enough to know for sure if this is my source.
I bought parts from RoverGuy. I had a virus attack my laptop and have been suffering intermittent internet service this weekend ( perfect timing ).
wiring conduit around elecrtical harnesses is so brittle it crumbles any time I move it. Makes me very nervous about removing lower intake manifold.Any advice is appreciated.

 

Thanks Borchera, I will try there.

 

After delays due to not having an 8mm 12 point socket, a 9mm hex drive and a wobble extension as well as holiday commitments; I have finally got the right side cyllinder head removed. The left comes off first thing in the morning(I hope).
My small obstacle is the bolt on the rear of the left cylinder head that retains the electrical harness. A 12 mm didnt fit, a 13mm was too big. A 1/2 inch seemed to fit just right. the only tool I could get on the bolt was an open end wrench which promptly rounded the bolt head. Does anyone on the forum know what size this bolt is?

 

Here's photos from hh65flyer of his rear of engine coolant leak....

 

Thanks for the photos Savannah Buzz. My gaskets were in much better shape than these photos. They looked good and were intact, which makes me suspect it was coolant leak from the jacket to the rear of the LH cylinder head. The piston adjacent to this coolant jacket was slightly cleaner than the other pistons but this may be due to my mopping up of coolant spilling into this bore during head removal. Leakage into this cylinder would explain the slight misfire I noted right before I shut the engine off for good before I started this job however. The heads were only slightly out of flatness spec. The heads are being milled and rebuilt presently. I had to use a bolt extractor to remove previously mentioned bolt.
All in all, so far so good. I broke the coolant reservoir to throttle body hose so will need to replace that. It was brittle as glass..... I will add a new belt, plugs and wires during installation. Anything else I should look at while I wait for my heads?

 

Do yourself a favor and get a block testing kit before you go any further. You can rent one from British Motorcars LTD. I went through all of the same things you are going through with my 2003 before finding out I had a liner that had slipped.

 

Thanks for the recommendation Outback Jim. Did your engine display any signs of a slipped liner? Which liner had slipped?

 

You could also remove front cover and do oil pump....

 

I was getting a trouble code of P0304 (misfire cylinder 4). I was also getting coolant system over-pressurization and boil-over. Once I got the heads off, cylinder 4 was a different color from the rest of the cylinders from burning coolant. When I connected the block tester, a bead of coolant formed between the liner and the block verifying it was the liner on number 4 that had come loose.