Thread: Toymota diesel probs

I don't understand how the exhaust gas gets in the rocker cover in this scenario?

Toyota injector is inside the rocker cover next to the camshaft and rockers. this is normal for common rail engines.


the injector on a diesel spray directly into the combustion chamber-piston.
the high pressure exhaust leaks past the seal into the rocker cover.


the seal is a washer that the injector pushes against. like the washer on a spark plug.


loosen a sparkplug and listen to the exhaust coming up the thread.

I still don't understand how these seals wear so relatively quickly. Surely if the seal is seated properly onto a cleanly machined surface, there should be no wear?
The only thing I can think of is that they corrode?
Why am I reading about this problem only on the Toyota engines?

Below is an interesting post from a Toyota forum. Seems 'contaminated fuel, not our problem' is the standard dealer answer for any common rail diesel fault.

"Have a turbo diesel Hilux, just under 100,000 k's, still covered by Toyota's Factory Approved Extended Warranty Insurance.

Hilux has rattled badly on start up, seems to be a common problem with these engines. I've put up with this as I was told it was "normal".

Recently, it has started blowing blue-ish white smoke when starting it (not just a puff, but a massive cloud). Cold rattle has become worse, it misses a touch at idle and seems down on power. Took it to a Toyota dealer, diagnosis is "You've picked up contaminated fuel somewhere". Justification is that fuel pump is slightly down on specifications (155000 kpa vs a specification of 160000kpa), front two injectors are well outside spec, although the rear two are perfectly within spec. Contaminated fuel = no cover under warranty.

Took it to a diesel injection specialist - diagnosis is that the copper seals between front injectors and combustion chamber have failed, combustion gases have got up to the O-ring further up the injectors causing them to fail allowing oil to run down past the injector and into the combustion chamber causing the smoke and also caking the injector in burnt oil.

Just trying to find out whether to go back to the Toyota dealer or to just give up and claim it on my comprehensive insurance, which covers damage from contaminated fuel. In this case, its potentially $5500 out of my pocket if I can't prove that, and if my comprehensive insurance agrees with the diesel specialist and decides its NOT a contamination issue.....

Actaully, its only $3300 if I get the diesel specialist to repair the problem using genuine new Denso injectors at $500-odd each. Toyota want $5500, their (exactly the same) Denso injectors are apparently worth over a grand each because they come in a box that says "Toyota". Or perhaps the injectors are $500-odd, and the Toyota boxes are $500 each extra ??"

You're probably right with the price for Toyota boxes LOL
I'd be taking a report from the independent guy and going first to the dealer, next to Toyota management. Paul Gover who is editor of the Cars Guide in the Melb Herald Sun seems to be able to get through to them pretty well. You'll find his email address on his column.
Good Luck!

There is a massive thread on this on Pradopoint. I just had a look on my phone but can't find it.
When I read it there seemed to be a lot of 120 Prados with the problem but 150s were not common. No idea about Hiluxs or Hiaces.

Coming from a 08 d4d hilux I never any of these problems. I read a lot of info on this before my purchase but I ended up buying one anyway(same with my d90), I think the problems stem from poor fuel quality and oil change intervals but that's my opinion. I did a filter and oil every 5k and it didn't miss a beat.

Originally Posted by WTF_D90

Coming from a 08 d4d hilux I never any of these problems. I read a lot of info on this before my purchase but I ended up buying one anyway(same with my d90), I think the problems stem from poor fuel quality and oil change intervals but that's my opinion. I did a filter and oil every 5k and it didn't miss a beat.

5000km changes are ludicrous. My 1985 isuzu 4BD1T is 16,000km.

Ford diesels also have some issues with injector seals. But injectors are outside the rocker cover so no oil gets in. Rather coal type deposits form around the injectors.