Replaced the head gasket on my discovery after it broke down and I was advised on this site that was what it probably would be, and thankfully it was! It now starts and runs (a bit smokey just now cos of all the water that was in the cylinders I guess) but the water is coming out of the expansion tank cap as it appears to be under too much pressure. Engine is quick to heat up to the middle of the guage and then just stays there. I've drained the system,and re-filled it and it's still the same, only thing is the heater doesn't get warm even though the engine's hot now. Thought it could be an airlock and that's why I drained it and re-filled it but it's still the same and I ran the engine with the caps off the top of the thermostat and radiator hoping this would cure it but it hasn't. Is there any other bleed points or ways to get rid of the airlock if that's what it is that's causing the problem?
Any advice would be greatly appreciated as I'm desperate to get to drive it again!
Cheers, Tam

Sounds like the head gasket job has not been a success.

Head may be warped or cracked ... or mating faces not properly cleaned as the gasket was fitted.

tam kite said:

Replaced the head gasket on my discovery after it broke down and I was advised on this site that was what it probably would be, and thankfully it was! It now starts and runs (a bit smokey just now cos of all the water that was in the cylinders I guess) but the water is coming out of the expansion tank cap as it appears to be under too much pressure. Engine is quick to heat up to the middle of the guage and then just stays there. I've drained the system,and re-filled it and it's still the same, only thing is the heater doesn't get warm even though the engine's hot now. Thought it could be an airlock and that's why I drained it and re-filled it but it's still the same and I ran the engine with the caps off the top of the thermostat and radiator hoping this would cure it but it hasn't. Is there any other bleed points or ways to get rid of the airlock if that's what it is that's causing the problem?
Any advice would be greatly appreciated as I'm desperate to get to drive it again!
Cheers, Tam

Click to expand...

Water can come out of expansion due to expelled air,if you have undone breather on radiator & stat,try filling with a funnel in the stat breather, just filled my system like you did after waterpump exploded on my 300tdi without any problems.

Heater not working is either knackered heater matrix,thermostat or an airlock!

Tried filling it up but after a while the temp gauge still goes towards the red and i need to switch it off before it gets too hot!
The level of water in the expansion tank seems to be rising when the engine is ran but no water will come out the breather on the top of the thermostat until the expansion tank cap is undone. I've disconnected the hoses one by one and they're all clear and water is flowing through them when the engine is running but it seems as if the water isn't flowing when it's all connected up properly! Any ideas anyone?

tam kite said:

Tried filling it up but after a while the temp gauge still goes towards the red and i need to switch it off before it gets too hot!
The level of water in the expansion tank seems to be rising when the engine is ran but no water will come out the breather on the top of the thermostat until the expansion tank cap is undone. I've disconnected the hoses one by one and they're all clear and water is flowing through them when the engine is running but it seems as if the water isn't flowing when it's all connected up properly! Any ideas anyone?

Click to expand...

Waterpump?

Took water pump off, all seemed fine with it by the look of it, got new gasket and fitted it all up again. Assuming it's fine and it's pumping water round because when you disconnect a hose the water is being pumped through it. Totally stumped with it and getting more and more f*$ked off with it every time I look at it. Thought I had it fixed after putting new head gasket on it and got it running but now this! Any other ideas?

Dam

Is the viscous fan working,it should spin freely when cold and be stiff when hot.

Needless to say check it with the engine stopped

Fan's working fine (nearly took my fingers off when i forgot to put the cover back on it after taking the water pump out!). I might be being really thick here but there's 2 hoses coming off the bottom of the expansion tank. The thinner of the 2 hoses goes into a sort of round thing (looks like it could be a non-return valve?)and 2 thin hoses come off the other side of it. 1 going to the radiator and the other going to the thermostat housing. I disconnected these pipes and found that water flows through them in every direction. Is the round thing a non-return valve? If so, seeing as it's letting water pass through any way could this be the reason for the expansion tank filling up and leaking out the cap? It may just be a fancy looking T piece if it's not a non return valve!
Cheers for your help so far Jason, hoping you can steer me in the right direction with this as I'm clueless!

it can only be a few things....

not enough coolant.
coolant not being pumped around to move the heated engine water to the radiator.
coolant not being cooled again after being heated by the engine - (blocked radiator)

do you have cool spots in yo radiator when up to temperature?
do you have any air locks? (dont forget to check heater matrix)

The round thing is NOT a non-return valve, though they do act that way when they get blocked! Yours is OK. I would reckon your head gasket is still leaking from the evidence.

tam kite

Try searching the forum as there have been a few others with the same problem in the past.

Apparentley the cooling system can be a right bitch to bleed if you do happen to get a bummer of an air lock in it which would also explain why your heaters not working!

Is the coolant level actualy rising back up in the expansion tank? (like being forced back by air) or has it got tiny little bubles in it?(Like duff head gasket)

I would agree with Jim , going from past experience . Last year a friend's Disco was behaving exactly like yours and having tried bleeding , filling through different points ( and even getting the heater to work for a very short time ) I finally removed the head , had it skimmed and when replaced everything was fine .
Did you have the head pressure tested when you had it off because some of what you describe is alot like a problem I had with my sister's Tdi last month and it turned out the head was cracked . She said she had a lot of smoke occasionally but I think it was steam as water was getting into the combustion chamber .
The confusing part was that the 'smoke' happened intermittently for a while , it could be on start up or a while into a journey and the gauge remained at normal . Eventually it did overheat , gauge went up and Disco was recovered to my house . It was sitting outside for about a week and when I took the head off there was about 50 cc of water in cylinder no2 .
Considering all the filling/ refilling you have carried out I would imagine you would have got rid of any airlock by now - I have found that if everything is as it should the Disco cooling system is easy enough to get working properly .

Coolant doesn't seem to have bubbles, just rises as the engine's run. Looks like I'm going to have to take the head off again and see if that's the answer!

First, the coolant WILL rise as the engine heats up - water expands.

Second, if there is any air of gas lurking in the system the water level in the tank will rise a lot - gas expands heaps when it warms up.

If the head gasket is not perfect, gas from one or more cylinder(s) may be getting past the weak bit of gasket and into the water passages, so no matter how much you bleed it, it will keep happening.

Don't give up yet though. Try filling the system as recommended, but in the first gallon of water add some Washing up liquid - no more than ONE teaspoonful. The detergent will have two good effects. First it makes the water WETTER so it wets the insides and in so doing dislodges any little air bubbles. Second it cleans, and helps to shift oily dirt and hold it in suspension in the water. Then run it for a while and see if that helps.

If the head gasket has leaked that is bad news, BUT, if it isn't blowing bubbles from the header tank you may get away with it yet - with the engine warm, re-tighten all the cylinder head nuts and bolts. Drain all the coolant water first to try to keep the head gasket dry. One by one, in the right order as per the book, undo the head bolts, take them out, wire brush the threads, grease them with a LITTLE copper-grease, refit and torque to about 80% of the full amount using a good clicking torque-wrench. Once you have done them all, set the torque wrench to about 10% MORE than recommended torque, and do them all full tight again in the right order. Then go over them all again at least once more just enough to make every bolt turn a tiny bit more. You are tying to nudge every one of them very tight without breaking them.

You never know - it might work.
Usually it does, but in this case .... it's a LandRover.

CharlesY

Cheers charlesy. Haven't taken the head off yet (been crap weather) so i'll give your advice a go and see what happens. Was told to get a pressure test done and this would tell me if it was the head gasket or just an airlock but I'll do what you've suggested first. Any idea how much a pressure test is? And how much a new/ good second hand cylinder head is? (thinking of worst case scenario so that things can only get better if I do need a new head)

have just had the same experience .Split return pipe from heater matrix into pump suction .Then flushed water through until a full bore flow came out..Re-connected .THEN reduced water level in header tank to normal level.This worked .And heater now works so well i dont have to have it on full blast .Pity i ripped out the carpets because it didnt get hot enough .
First try the internal heater got hot when going uphill and cooled down when going down.

take the head off and get it tested that way you can be sure there is no problem