300 tdi overheating and eating turbos!

Ok, here goes.............

My 97 Defender 90 has had me pulling my hair out! Basically it will start to overheat when driven 'enthusiastically' or when towing.

The hotter it gets the slower it gets..... The slower it gets the more throttle is needed..... The more throttle is needed the hotter it gets.... So it goes on.

It has now eaten 3 (yes 3!) turbos in as many months. All suffering from heat cracks in the exhaust housing.

Heres what I have changed or checked...

New radiator
New water pump
New hoses
New thermostat
New Auxillary belt tensioner (thougt maybe belt wasnt driving fan well enough)
New head gasket (it was at that failure mileage, and removal proved that it was failing)
New injectors
S/h injector pump (pump timing has been checked and double checked! Fueling is increased but no excessive black smoke)
New lift pump
Fuel lines checked for blockages
Intercooler flushed (full size one)
De-cat front pipe

The engine has covered 123k (about 100k of towing), does not use oil or water or seem to have excessive crankcase pressure. It starts on the button every time rain or shine.

As you can see I have covered all external components and am left thinking that its just plain worn out and it just cant take the extra work of towing or driving at speed.

Anyone got any ideas or had a similar problem? I am on the verge of going the 2.8 route...

are all the turbo hoses in good condition internally? does the turbo give good boost and is the boost getting through the pipes and intercooler and into the engine?
the fact that it uses no oil or water would make me discount the mileage as being an issue. Mine is on 155 thousand and goes like a good 'un.

All the hoses are also new, the only part of the induction I cant easily check is the core of the intercooler. I have a boost gauge fitted, and the turbo is showing good boost pressure (about 16psi):biggrin1: but it is connected at the compressor outlet and not at the induction manifold. Maybe I'll try to fit it at the manifold and see if there is a pressure difference across the intercooler.

Thanks for the idea! Its got me thinking again.......

I would expect that you would see pressure drop of a few psi at the point the air goes into the inlet manifold, can you hear the turbo whistling when it is boosting? you could try removing the turbo hose that goes from the intercooler to the inlet manifold, then get your glamorous assistant to raise the revs on the engine, you should be able to see the turbo hoses bulging with the pressure and feel the boost coming out of the hose....obviously be careful doing this........i wonder if ther is a blockage in the inlet manifold itself?

There's a lot of talk about exhaust gas temperatures, maybe with the slightly increased boost and injector pump, the temp's gone a bit high. would an egt guage be worth a look?

Thin_trucker said:

There's a lot of talk about exhaust gas temperatures, maybe with the slightly increased boost and injector pump, the temp's gone a bit high. would an egt guage be worth a look?

Click to expand...

naaaah not in my opinion, i have had mine up to 760 degrees and had no bother, i run maximum boost that the turbo will give whicj]h is about 21psi.

one thing i thought about was why have the turbos failed in the past?? is it through oil starvation? is the oil feed pipe to the turbo clear??

if possible try bypassing aftercooler sounds like the turbo is working hard to get air.
go to halfords and buy one of those cheap cone filters and clamp upto the turbo,take for a run and see what happens. check and clean intake manifold and wouldnt be a bad idea to get the exhaust temps checked. as stated above check oil and coolant lines for the turbo. hope this helps

Some interesting opinions there.

The turbo spins well and does expand the hoses when revved. But I have noticed the the boost doesnt seem to increase performance in comparison with the amount of whistling going on! There are no leaks on the intercooler hoses etc, so I might try bypassing the intercooler and go for a 'short' run...

Also I have an egt gauge fitted (after second turbo!)so I can keep an eye on the fuelling.

sounds like low oil pressure or oil getting cooked, could be head gasket blown and cooking oil way, unless it got enough oil it wouldn't run away.

I'd be looking at oil temp and pressure.

any joy yet?