I've pulled the passenger side head (drivers ones proving to be annoying!) but i'm curious about some of the findings.

The engine was pressurising the cooling system, slightly, and using coolant, but drove fine and you could do 100's of miles in it a day without issue. Lots of short trips seemed to guzzle coolant, but a long trip would only use a little, suggesting it was leaking more when cold perhaps?

Spark plugs on 1 and 3 would turn orange over time. Its been like this for several years and i've finally decided to fix it as it seems to (finally!) be getting worse with some signs of water on the other bank.

I'm particularly curious having removing the head though, of how exactly its ended up the way it has.

Examining the head and pistons, you can see that 1, 3 and 7 all appear to have signs of steam cleaning, with the clean areas of the piston crowns and clean areas of the head. 5 looks pretty normal.

Moving over to the gasket, cylinder 1 has obvious rust on the firing ring, so we can imagine thats certainly a path between the water jacket and cyl 1. Oddly enough for the cylinder with the most obvious water route, its the dirtiest of the three cylinders. Cyl3 has a small amount of rust on the fire ring too. I guess i'm pondering how water got into these cylinders in the first place to rust the fire ring though... Especially 3, it doesnt appear to be near any water... Cyl 7 fire ring looks fine, infact theres nothing obvious at all around cyl 7, so not sure why its showing signs of steam cleaning. It is ofcourse adjacent to the water jacket, so it certainly could be leaking across from there.

Is there anything else i can check while its apart? Cylinder liners being the obvious question mark.

Ive put a stream of photos on imgur: https://imgur.com/a/PyyyvxJ

i looked at the pics of the gaskets and i did not see any thing wrong with them, sorry.

Gasket looks reasonable I'll agree but one of the fire rings is split and the stains on the head show a leak at one end. The pistons and combustion chambers aren't showing the normal steam cleaning you'd expect with coolant getting in although orange tip to the spark plugs is usually a sign that anti-freeze has been getting into the combustion chamber. It may be that you have a very slight leak around the outside of a liner, so it hasn't slipped but may be leaking. If that is the case, the options are a rebuild with top hat liners, or a dose of water glass in the coolant depending on how much mileage you do in it. The water glass will last for maybe 50k miles or so.

someone on another forum suggesting that these marks are potentially signs of liner leaks:

Dont do a lot of mileage TBH. Few thousand miles a year.

I guess i clean everything up and reassemble with the new heads and fresh gaskets and see what happens. If its still leaking coolant then give it a dose of water glass.

I held off from using it before as i had the red long-life coolant in it, apparently its incompatible with that?

Marks could be signs of a liner leak but they could equally be slight distortion of the fire ring. One other thing I noticed is that the Elring logo and part number are still easily visible on the gasket which could suggest it has been apart before and wasn't torqued down fully. I assume it had stretch bolts rather than studs and doing the 90 degree turns can be a pain. You need a long bar so you can get enough grunt but then the bar hits against other things around it. If you put a long extension on the socket , it can twist when you are heaving on it so you don't get the full 90 degrees. Did they come out easily or did you need to use a breaker bar on them?

It was rebuilt by landrover sometime around 2000ish I'd need to dig out the receipts, but i think they replaced the heads then shortly thereafter replaced the shortblock. Dont think its been touched since then though.

They were pretty tight, needed breaker plus cheater to crack a lot of them off.

Just checked. There was some sort of headgasket failure circa May 2000 at ~91k miles, it appears it was recovered to landrover cardiff and they replaced the heads with new units, but recommended engine block replacement due to "hot spots and scoring on the cylinder block". Its quite hard to make out all the details as the invoice is a fax on ancient faded thermal paper. However you can make out the basics and theres a charge for two new heads etc.

Then October 2000 there is an invoice from sheffield landrover, who replaced the short motor, along with all the gaskets etc that you'd expect.

Oddly enough, the car had only done 10miles between the original failure, and the Sheffield invoice.

Finally got the other bank off. Cyl 8 was fully steam cleaned on this bank. Oddly enough thats also the cylinder that fouls its plug with oil. Valves were even covered in horrible rusty deposits.

Drivers manifold fought me the whole way, one of the bolts rounded off, ended up removing the head with the manifold (which was also a challenge getting the head bolts out with the manifold in the way...)

Found that despite internet lore suggesting they are metric, both the new heads from the Thor engine, and the old (replacement) heads used 3/8UNC threads for the exhaust manifolds. Both were dated "00" on the castings, so they're both from 2000ish. So i've had to order up a set of new bolts for those. One of the manifolds also has a cracked Flexi, so i need to do something about that.

Two of the cylinder walls looked somewhat unhappy on this bank, sorta marred up and definitely not the usual shiney crosshatched look.

Oh and ofcourse the lifters are all dished and the camshaft looks a bit crap, as expected.

Not sure how to proceed, on the one hand the camshaft does need replacing, on the other i'd be super pissed if i replaced it, built the engine all back up and discovered it was still leaking coolant...

I think i'm leaning towards just putting it back together and see how it goes. If the head gaskets have fixed all the coolant issues, then i'll need to pull the top off again and do the cam and lifters. At least the actual heads (and those bloody manifolds!) dont have to come back off for the camshaft work.

Still chugging away at this, thought i'd post a bit of an update. Things have been slow due to the awful weather we've had.

Heads went back on a couple weeks ago. Put the valve train together and then spun the engine over on the starter until i could see oil appearing out the rocker shafts. Noticed a few of the lifters werent spinning that well, though it did seem to improve once the oil pressure came up. Clearly, it needs a cam, but the main point now is to figure out if the rest of the engines worth fitting a cam to!

Last weekend i started on the exhaust manifolds. All the downpipe studs were ruined and snapped off trying to get them out. Ended up drilling them all out, and welding in bolts to act as a stud instead. Welded up a small hairline crack on the nearside manifold collector. The offside manifold had a split flexi so i bought another manifold from ebay (also with ruined studs) and gave it the same treatment. Bought a set of new bolts (3/8" UNC Zinc plated cap heads) along with spring and flat washers. After what felt like two whole days of messing about i finally had two usable manifolds attached to the engine. Tightening up the offside manifold lower bolts was somewhat awkward, i ended up cutting a 5/16" allen key, and using that with a ring spanner over the end to tighten them. getting a ratchet in was impossible for the rear two (at least without removing the steering shaft). NO idea why they didnt just move the engine over an inch in the bay...

Yesterday i finally got the intake reinstalled. Repinned the crank sensor plug into a new housing, the old one was cracked and held on with zip ties. Got all the wiring back together for the EFI, installed spark plugs (although realised i only had 6 new ones, so stuck two old ones in for now). Attached the alternator bracket for engine earth, then decided to see if it would fire... Lit streight off first turn, at which point i realised i hadnt bolted the downpipes on 😂. It also died after a few seconds. Intake had various vacuum hoses not fitted (EVAP, fuel pressure reg, LPG) and the throttle cable wasnt attached. Sorted all that out and fired it up again, and it sounded fine and settled into a 1000rpm idle. Didnt leave it running as theres no coolant in it, but at least it works!

Then i went indoors onto ebay and ordered more spark plugs, a serpentine belt (the shorter non-AC one, will leave the AC bits off for now), a coolant hose set to replace the hoses that have gotten deformed from the engine pressure and an air filter. I also discovered the water pump pulley was wobbly, so i ordered a water pump while i was there. So much for not spending money on it until i'm sure its good...

Still need to reinstall all of the cooling system. I also need to get inside the cab and do the heater core o-rings. Maybe next weekend it'll drive around the block!

Aragorn wrote:

NO idea why they didnt just move the engine over an inch in the bay...

If you look, it isn't central anyway, it is offset towards the drivers side as the propshafts run down the passenger side.

Finally got it completed on Saturday. Well mostly.

Dug out my new and old coolant hoses and spent some time swapping those onto the thermostat. Lots of time spend fighting with the constant tension clamps as the new hoses were thicker than the old ones and a few of the clamps simply werent large enough. Fitted a new water pump as the old one was wobbly.
Dismantled the dashboard to get at the heater core o rings and installed some nice fresh Viton 22x2.5 o-rings. Spent some time trying to fix the hacked up ducting as someone has cut the horizontal duct that leads to the drivers face vent. Broke the end of the dashboard in the process, but the ducting is now very neatly taped back together.
With that done i finished up the engine bay coolant lines (left the LPG stuff out for now) and fitted the replacement serpentine belt and filled it up with coolant. Fought with the fan shroud but eventually persuaded the thermostat into the small slot. I havent refitted the fan yet.

With everything done i popped the grille back on and took it out for a short drive. Everything seems to work. No pressure in the cooling system after it cooled down. Coolant level dropped a bit but i'm assuming its just working the air out the system. Topped it off and done another slightly longer drive to screwfix on sunday morning. I think the engine actually sounds quieter, there was a tickyness previously which has gone (perhaps the exhaust manifolds?). It doesnt feel any peppier than previously and still sounds fairly harsh at high RPM's, i presume mainly down to the camshaft and chain.

So i guess now i need to put some more miles on it and try to get a feel for whether or not the cylinder liners are leaking. I want to re-do the coolant pipework for the LPG system so i'm going to order some 10mm hose and will plumb that in and get that back up and running at some point, but for now it can stay on petrol until i get those bits sorted. And i need to refit the fan at some point, dislike those things so i quietly ignored it for now. I also need to reinstall the manifold heatsheilds. If the coolant issues seem to be fixed then i guess the next step is ordering a camshaft and associated bits.

Seemed to be still using a fair amount of coolant until i noticed it was all over the side step, the hose into the coolant bottle wasnt clamped up properly. Fixed that and i've done another 50 or so miles in it, and its now much better, however i'm noticing there is still some pressure in the cooling system after a drive.

For instance i topped it off on sunday morning, the wife drove it to work and back yesterday and this morning i've just checked it again, and opening the tank made a big "tishhhh" noise. Water level has dropped a very small amount, maybe a few milimeters below the line.

Some pressure build up is normal. The coolant system is a closed system, unless the pressure builds above the relief cap setting (20 psi IIRC). As the coolant heats, it expands building up pressure (because the system is closed). When it cools down it will contract about the same amount and you won’t notice any pressure differential when removing the cap.

It'll pressurise when hot but the pressure should disappear once it has cooled right down. Unless you have an air lock in there when it won't. If, when cold and with the cap off, you can squeeze the top hose and hear gurgling, there is still air in there.

yeah exactly my thoughts... I would expect pressure when its running, but it should go away when its cooled down.

So pressure when cold suggests compression is getting in.

Fairly sure its not airlocked, it took over 10L of coolant and runs nicely upto operating temp and sits there.

I'm going to T in a pressure gauge and see if i can see whats going on.

I own a vehicle with a V6 engine that has a blown head gasket, it pressurises the cooling system when running and even if I let it cool down then leave it cool for a few days before opening the rad cap there's still pressure in the cooling system.

I strongly suspected it had a hg problem but confirmed it using a sniff test.

I have cooling system pressure test equipment which I intend (when I finally get around to it) to use to try to identify which hg is leaking by pressurising the system when it's cool and see if I can see any coolant weeping into cylinders using a borescope through spark plug holes. Not sure if this will work though, because it obviously leaks whilst running (when there's a lot of pressure in the cylinders) but seals against the smaller pressure in the cooling system with the engine off and/or cool... So maybe this won't work because even if I pressurise the cooling system to (say) 5 bar pressure that still won't be enough pressure to cause coolant to leak into cylinder(s), and such pressure could be enough to ruin the hg that currently isn't leaking.

The most likely problem if there is a leak will be around the outside of the liner, the block to liner joint which is within the fire ring of the gasket. That is a prime candidate for waterglass which will stop it for many years. You can either buy waterglass with a dye in it called Steel Seal, or for about a fifth of the price, plain waterglass without the dye https://www.ebay.co.uk/itm/224517468608. You'd want to put about a litre in, and follow the instructions for Steel Seal https://steelseal.co.uk/how-to-use/

I tried Steel Seal in my V6 which will have a liner because it's an all aluminium engine but it still has the same symptoms. Not sure if I followed the instructions exactly though, the car hasn't been on the road since but I have fully warmed it up and left it running for quite some time.

At 150K miles when my Vogue was overheating in desperation we used three bottles of Steel Seal. This fixed the problem & lasted for over 25K miles until the head gasket started blowing & this time I had the engine completely rebuilt by V8 Developments.