help with my td5 please

[capel]

Hi there,
I have a 130 td5 '99. I have only had it for about 5 months. I picked it up in the Summer, and it went through the Christmas break (43 on Boxing day) with no issues doing 150km trips to the sth coast etc. About a month ago I hooked up a small 6x4 box trailer and headed out for a load of wood, upon returning, the water was bubbling past the expansion tank cap.
I refilled the system with coolant, and checked the cap, the seal of the cap was forced into a shape that had it pushed out into the channels that the hot pressurised air normally escapes from. I assumed the cap wasn't letting the pressure escape, then the pressure forced the rubber seal to distort and fail. but before the seal failed, the little rubber hose fitting below the turbo developed a pinhole and the pressure not only forced the coolant out the top, but sprayed it all over the turbo, so I had a handy warning smell alarm entering the cab from the vent as I headed into town.

I have replaced the cap, and the rubber hose, and bled the sytem properly, and all seems to be ok. I have done a few 200km trips and everything is seemingly normal.
I am concerned though, that the engine produced this sort of pressure in the first place. Something had to give, and those item I mentioned failed, but I can't understand how a 100km/hr run at 40 degrees didn't affect the motor at all, but a lazy 10km wander into the bush had it boiling.

Would a head gasket be responsible, or is it as simple as the expansion chamber cap?

I have an '01 disco td5 which is a gem, I've replaced a few parts on it, but I have owned it from new, so know all her character traits. But this is fairly shaking me. This vehicle was going to be my holiday 'let the kids in with sand on their feet' truck, but I'm not so sure.

Any help for the "only just mechanically competent' defender owner?

Cheers, Craig.

[davenlone]

check that the thermostat is operating correctly. If its decided not to play the game you'll boil and have head gasket like symptoms within about 10 minutes. If its operating at normal temprature now id just keep an eye on it for leaks ect.....

If it was a head gasket problem, it would still be present after changing the cap & bleeding the system.

[George130]

The standard cap will hold 20psi. A small leak will also be capable of succing air into the system. The air heats up and expands pushing coolant out.
Keep an eye on the system for now. If it runs hotter or keeps loosing coolant you have a problem.

[foz.in.oz]

By pressurizing a cooling system you raise the boiling point of the coolant. Therefore when you have a leak passed the cap as in your case the coolant is not under pressure and will boil at around 100-105°C as apposed to above the normal operating temperature of the engine. This generates a lot of steam which will push out lots of coolant also. However, if you are lucky, which sounds like you were, as long as the coolant is flooding the engine waterways little or no damage may be possible. If you've fixed the leaks and the temperature guage is reading normal you should be ok. Keep a careful eye on levels for a while and see how it goes.

Ray

[capel]

Thanks to all replies, very informative, I'm learning slowly!

I don't think the news is terribly good on the water front, I am topping up about 1L after 200km's. This doesn't seem 'normal' to me ..... any tips??

Cheers, Craig.

[George130]

Doesn't sound good.
If you are certain that you have bled the system properly then I would get a pressure test (Mine passed with a blown head) and also the exhaust gas chemical test done.
TD5 head gasket will gost a couple of thousand by a workshop. Major head repairs will cost even more. $4000 when I did mine with me doing the strip down, delivery and assembly work.
I would also check the thermostat if you can get it out. I know mine was jammed.

[Blknight.aus]

the other thing that might do it could be if its had the wrong coolant in it at some time and the radiator or thermostat is slightly sludged.

if your working the engine slowly the pump may not be shifting the coolant effectively enough for the system to do its job.

[capel]

More thanks,
I'll do the tests required.
I'm not too happy!

Cheers, Craig.