getting hot under loaad

A week or so ago my 300tdi disco started getting hot under load. I stopped let her cool down and discovered she'd emptied her expansion tank. So I refilled her and carried on with no further overheating. Went to go home again and noted that the expansion tank was down again so filled her up a chucked a bottle of rad weld in as I can't find any obvious leaks. N ok wetness under car or under bonnet and no obvious leaks from the rad. Anyhow all well until today when with a trailer on the back she started getting hot on a long steep hill. Again no signs of a leak and running at normal temp when not towing.

Any ideas what to check once I've got her home appreciated as I need her to tow 2 tonnes tomorrow and I don't want to cook my engine

Thanks Paul

check rads hot all over core when engines hot and be prepared to change head gasket

Just checked the water level and shed lost about 1litre over the last week to 10 days. There was still plenty in the expansion bottle it was maybe 1/2 a centimeter below the seperation line.

Big long hill on the last leg home about 4 miles steady uphill climb at about 1:7 with the disco pulling trailer at 45mph in 4th gear didn't get hot in the slightest after adding the 1 litre to the cooling system.

Is there any way to tell which thickness gasket id need before removing the head?

if you look at a tab on gasket between the 2 rear most injectors, check rad

Checked her again just now and it had lost that litre of water. Rad is evenly hot all over started her up and the idle is a little rough she is hunting slightly, she feels slightly down on power and the expansion tank pressurised in less than 20s. Putting my hand over the expansion bottle with the engine running and I can feel a rhythmic pulsing in time with the engine so I think that pretty much confirms a failing head gasket.

Well that means I wont be collecting my new tractor tomorrow as towing near to 3 tonnes behind her with a blowing HG is not going to end well

Been getting stuck into this job this evening and all was going nicely until time came to remove the manifolds. Inlet off easy no problem, exhaust now that isn't so easy is it. Im sorry but how in the world do you get to the centre lower manifold stud undone. I can't see it I can only just feel it getting a spanner to it is an art form and if I do manage I can't get enough leverage to undo it. Now I thought no problem I will just have to drop the down pipe off and take the turbo and exhaust manifold off with the head, scuppered there too someones been there before me and rounded the nuts off. Other than one stud holding the manifold on or 3 studs holding the down pipe on all thats left to do is drain the cooling system and undo the head bolts.

Out of interest is there a block drain tap on these engines and if so where is it? I'm hoping there is as I don't really want to fill up all the bores when removing the head.

The block drain plug is on the right hand side of the engine, looking from the front towards the back of the vehicle. Its toward the front of the engine, about half way down behind the alternator. 13mm. Can't miss it; its on its own.

As for the exhaust bolt. There is always a way. Keep trying Just make sure you're using the right tool for the job.

I had my eggsauce mani off last weekend and the bolt was a pain in the arse , I had to go though my spanners till I found one that was right shape to fit it was a ring spanner with a slight bend to it ,only had a slight bit if movement but it was enough to slowly turn it out took ages

Done just waiting on a new manifold gasket to see if she is fixed

Well I couldn't resist seeing if she was fixed so put it back together with the 3 part broken manifold gasket to see if she was fixed.

Well power wise no difference but I don't think she was down on power really anyway temp seems to be staying put at 1/2 way up the gauge again and not moving so that looks good that was on about a 10mile round trip. Expansion tank level has stayed the same and can no longer feel pulsing with hand over filler cap hole and its no longer pressurising. So far its seems good we shall see how well it runs when given a proper run tomorrow, there is a chuffing noise from the manifold area but that was to be expected given the state of the manifold gasket and annoyingly she is still slightly hunting at idle