Loss of coolant from 2001 TD5 Defender Xtreme 110

G'day all. I'm wondering if the great wide world of Defender enthusiasts has come across the problem that my Defender has developed. It's loosing coolant through the pressure cap, but only when I've driven it for about 40 kilometres (25 miles) or more. Below that mileage everything is OK - the top hose is rock hard and there's no loss of coolant. It loses almost a litre of fluid on a round trip of 160 kilos to work and back. I have an EMS2 engine monitoring system and all readings are normal. EGT about 400 degrees C. Coolant temp 86 degrees after 5 kilos rising to max of 96 a few kilos later, though normally runs about 92. No perceivable loss of power from the engine or steam from the exhaust. I've tried 2 new pressure caps without them making any difference. Engine has done nearly 270k kilos. It's got me beat, so any thoughts on the possible cause would be greatly appreciated. Reg from Victoria Oz

Reply to
Reg Slawson
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Burning fuel produces so much water anyway you wouldn't notice 1l extra...

Any sign of water in the oil, no emulsion under the oil filler cap?

Checked the seat in the tank for damage or any cracks? Get a UV lamp out in the dark to look for the leak. I *think* additives in the antifreeze fluoresces under UV making finding small leaks a bit easier.

Reply to
Dave Liquorice

Hi.

I don't know what the presure cap is suposed to be rated at for the TD5, but "Rock Hard" coolant hoses are rarely a good sign. That would indicate quite a bit of presure has built up in there. Even at 15PSI, there would be some noticable "give" in the hoses to a "good squeze".

Other engines (gas/petrol and diesel) can and do sometimes develop leaks between the cylinders and the water jacket, so that the coolant system becomes presurised when the engine runs. Sadly, they rarely if ever fix themselves in a good way.

As Dave L said, check for water in the sump, or emulsion (mayonaise like stuff) on the inside of the filler cap after a short run, enough to get some heat in the engine, but not fully up to working temperature, as that can then drive out any moisture that is in the wrong place, so you wouldnt see it.

There used to be a coolant aditive available that would vividly change colour if any combustion gasses got into the cooling system. I've no idea what it was called, or if anything like that is still available, but if it is, it might be worth a try as a check to be sure something like the head gasket isn't leaking when hot, or a crack in something more expensive has not developed.

Take care, presurised hot water is not nice to be around, if it suddenly "gets out".

Regards.

Dave B.

Reply to
Mr Dave Baxter

Most, if not all garages in the UK have a tester which they fill with that additive, and use it to check for both pressure in the system and exhaust gasses. The test only takes a few seconds, and, IME, they'll often do it for not a lot of money, especially if there's a chance they'll be asked to fix the problem.

Your nearest motor factor will be able to get the kit, though at about GBP200, it's a bit dear for a one off test. Failing that, start from cold with the cap off, and use the palm of your hand to check for pressure, and have a sniff for exhaust smells at the opening.

Reply to
John Williamson

Sounds very much like a head gasket Reg. We're seeing a few up here in Qld now that the warmer weather is approaching. Considering your km, it would be a great opportunity to renew the injector seals and renew your injector loom to keep the oil out of your ECU. I'm a mechanic up here, so if you need any info shoot me an email. We can supply new or used parts too... but that's not my department unfortunately (or fortunately, whichever way you look at it.)

Craig. British Off Road, Qld.

Reply to
CraigB

Thanks for the thoughts guys. I have checked the oil but as my shortest trip is usually 10 kilos and nothing has shown up so I will take a look after a few kilos next time. Will also take up John's recommendation about pressure testing if my nearest radiator people can do it. Reg

Reply to
Reg Slawson

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