[martinbo]

Two weeks ago I overtook another car and thought to myself, hell it is "lekker" to have this power in a car. Then I heard a whistling noise coming from the turbo (no lack of performance, at all).
I service my Pajero, on the service intervals as suggested in the manual, at the agents and as it was due for a service, I asked them to check the whistling. To my horror they discovered the following:

Shaft worn and what happened to the fins? Where are those pieces?
The Pajero is on 203700km.
Fitted a new turbo from CRD for R13000. No new turbo at the agents, 3-4 weeks delivery and price R16000

[CATS]

I don't know turbos by a long stretch, so would ask some questions that I think could be relevant.

1.Was the wastegate on the old turbo still in good working order? A stuck wastegate could potentially lead to overboost.
2.What boost pressure was run on the turbo? Normal or slightly higher to improve performance? Overboost lets more gas run through the turbo leading to higher heat retention?
3.Was it ever "tuned" pr "chipped"?
4.What EGT's are you running as a norm? If you have an EGT gauge fitted this is easy to see and makes for interesting reading. High EGT could melt the turbo blades over time?
5.When last was the injectors checked for proper spray patterns? Incorrect spray patterns can lead to hot spots and high EGT's?

If you say the car was always serviced and oil changes done at correctly specified intervals, I can only assume that the blades got eaten up by excessive heat. Remember that Exhaust Gasses run anything up to 700deg Celsius !! This can easily eat your fins and if the cause is not found you will be in for the same again in time to come.

Remember that I am just asking questions here and may be totally off with my conclusions on why a turbo can end up looking like that, thus the question marks behind my 'statements' . I am just very interested in the reasons as I am also standing at close to 250 000km on my Pajero on the original turbo. On a diesel engine I believe that injectors is a constant check item and that somewhere in the life of the engine that one would probably need to look at replacing/servicing the diesel pump and turbo. The question I would like to know is when?

CATS

[4ePajero]

Shaft worn and what happened to the fins? Where are those pieces?

If you take into consideration that the turbo spins at 100 000 + rpm, that was a tiny particle that started the carnage!
Anything larger would have totally destroyed the impeller!

(It could eg have been a very small stone, left in the inlet when they serviced the air cleaner, the high revs when you overtook, was enough to pick it up, and the rest is history.)

Where are the pieces?
Out through the engine and the exhaust!
If any piece got stuck, you would have known about it by now!

PS Where is the old turbo?
Don't get rid of it.
Do you want to sell it?

[martinbo]

I have the old turbo and will send it in for refurbishing as a spare in the future.

[4ePikanini]

NB: the stuck wastegate causing overboost won't kill a turbo due to boost. It kills the turbo due to higher rpm than designed.

[martinbo]

CATS
1.The normal noise of the wastegate opening when you are going uphill under load was present. I experienced this quite a few times in April when towing my Kavango to the Kruger or maybe this was already the fins catching the housing
2.I did not increase the boost of the turbo.
3.SAC fitted a chip on 100000km's and removed the catalytic convertor.
4.EGT temp's I can't tell you as there is no gauge.
5.The Pajero's diesel pump developed an oil leak November last year and it was fixed by Mitsubishi East Rand, I suppose they will have calibrated or checked the injectors.

Lately the Pajero was smoking under load going uphill. This smoke was black and since the new turbo, no more. I guess with the worn blades the boost wasn't enough and over fueling happened

[CATS]

NB: the stuck wastegate causing overboost won't kill a turbo due to boost. It kills the turbo due to higher rpm than designed.

How does the turbo fail in such a case? Does the bearing fail and thus seize? Or does the bearing fail and the shaft gets additional sideways movement, thus leading to the impellers grinding into the turbo housing?

I am trying to understand what could possibly go wrong on a turbo. It seems that any particle reaching it could potentially do the damage as shown in Martin's case. Can there be other causes?

What is the normal cause of turbo failure?

Does a car stop in its tracks on all turbo failures? I assume not as Martin still drove his like this. Or is this not a true 'failure' of a turbo, but only one on its way to total failure?

Sorry for highjacking this thread - possibly I need to start a new discussion if we keep on for too long.

CATS

[HBannink]

I would go with the small particle. At the speed these babys spin a grain of sand is like a brick

[RoelfleRoux]

CATS,

I'm with you on this one! Hugely interested in the turbo system and hugely uninformed.

So if the guys are not complaining about the slight hijacking of this thread, lets play some more.

Is it the inlet side that failed?
Is the outlet still fine?

If the answer to both be "yes", then the fuel-supply and EGT shouldn't really have played a big role. If the chip increases the boost, then maybe the added pressure could have had something to do with the failure. Visually the turbo seems to have been physically destroyed by a body (foreign or maybe a part of itself). Either way, the debris would have moved on to at least the intercooler. Luckely the intercooler sits low and it seems that nothing found it's way up into the cylinders. If it was my car, I think I would look at the intercooler for lose bits or even internal damage.

Cheers
Roelf

[CATS]

CATS,

I'm with you on this one! Hugely interested in the turbo system and hugely uninformed.

So if the guys are not complaining about the slight hijacking of this thread, lets play some more.

Is it the inlet side that failed?
Is the outlet still fine?
Roelf

Roelf

I agree. This case seem to indicate no EGT issues but rather foreign matter that entered and damaged the fins.

Mention is also made in the first post of the shaft being worn. Why would this be the case? Surely this is not due to the foreign matter?

Where are the TURBO experts to try and educate me and Roelf here - PLEASE?

CATS