Disco 2 TD5 lost all coolant - HG check advice

[Munzy]

Hi all,

Unfortunately my Disco 2 TD5 lost all its coolant on the motorway yesterday. A terrible sludgy mess everywhere. I felt a small jolt whilst driving and looked down to see the temperature gauge rapidly falling to the cold position so I immediately pulled over and had the car recovered home.

I’ll start tearing it down next week and I’m hoping I’ll find that the oil cooler is shot hence oil escaping into the cooling system. The car runs fine, very smooth and there is no sign of mayo under the oil filler cap. I don’t think it’s the HG or head cracked at this stage.

I’ll strip all the cooling system down, clean it up and replace whatever needs fixing. What I want to know is how I can best test for a HG or head failure at this point. I wouldn’t trust one of these analysers looking for exhaust fumes in the expansion tank since the cooling system is in a right state.

What would be the best way to check do you think? It wouldn’t be the end of the world to rebuild the cooling system and see what happens but if I can do it all at the same time before rebuilding it would save a couple of hours.

[Vince Green]

first thing is to flush it out and refill it with water, run it up to temperature and look for leaks. it could just be a hose gone somewhere. Don't start stripping things till you know why you are stripping it.

Alternatively get a pressure tester, they are cheap 

Edited July 25, 2020 by Vince Green

[Munzy]

Yes good idea, I’ll clean it all up and do exactly that.
 

By pressure testing do you mean cylinder compression? I’ve got a gauge kicking around somewhere.

[Cannon]

A cylinder compression test is a good way to identify loss of compression, but it won't necessarily highlight the cause of the loss of compression. You would also need to make sure you use a diesel rated compression tester/gauge, as a petrol gauge can easily fail if connected to a diesel engine. When head gaskets fail they don't always fail at the top of a cylinder. Check the oil for contamination first. If everything looks ok with the oil I would refill the coolant system and do a pressure test using a coolant pressure tester. It makes finding leaks a lot easier.

[Saltings]

try one of these first https://www.ebay.co.uk/itm/DX-1-COMBUSTION-LEAK-TESTER-50ml-TEST-FLUID-for-DIESEL-HEAD-GASKET-BLOK-TESTER/254655209990?hash=item3b4aa22206:g:D58AAOSwXetcb~Xv     just in case  second oil cooler  

[al4x]

If it’s dropped out underneath then you have a leak, re fill with water and start up while looking for it underneath 

[Stephen-H]

5 hours ago, Saltings said:

try one of these first https://www.ebay.co.uk/itm/DX-1-COMBUSTION-LEAK-TESTER-50ml-TEST-FLUID-for-DIESEL-HEAD-GASKET-BLOK-TESTER/254655209990?hash=item3b4aa22206:g:D58AAOSwXetcb~Xv     just in case  second oil cooler  

100% agree try this after having a good look around the obvious stuff first 

[VicW]

When I had a head gasket blow it failed between a cylinder and the engine coolant jacket and blew all the coolant out of the overflow bottle.It made a right mess. Pressure tests failed on both the cylinder and the coolant system.

Vic.