Thread: Oil from Turbo question

Hi do you know how long the turbo sat without use? The seal could have gone hard. A blocked air filter will produce lots of black smoke. Its extremely unlikely the filter is causing the oil to bypass the seal, as the turbo will still be making some boost.

Originally Posted by disco63

Gday all,

I have just installed a turbo on my isuzu. I set the fuel for suitable EGT's and have wired shut the wastegate this afternoon. It is a T25 off a nissan patrol on a 4be1.

After a short drive, only 20 minutes there is oil leaking from the crossover pipe (turbo to intake). Obviously oil is passing the compressor seal.

I haven't done anything to the crankcase breather yet, still a NA one, could high crankcase pressure cause this?

My air filter is also knackered so could this also cause oil passing the seal?

The turbo housing had to be rotated to fit the isuzu but was only rebuilt 40,000k's ago, could I have damaged a seal by rotating the compressor housing?

Any help is appreciated.

If your air cleaner is completely blocked, I suppose that excess vacumm in the inlet could pull oil from the front turbo seal. Would need to be completely blocked and I can't say this is something that I have seen, interested to see if others have. Would imagine very low power and heaps of black smoke.

Can you clean the oil out and drive without the air filter in and see how that goes?

Cannot be a dry seal in the turbo as no rubber seals in there and rotating the housing will have no effect on the seals either.

Could it be that the turbo is just knackered? Is there much free play in the turbo main shaft when you lift it up and down.

Where is the crankcase breather plumbed in? If its in the inlet is it having oil dropped in front of the compressor wheel?

Is there a difference in the oil pressure on the nissan engine to the isuzu engine, not sure if this would have any effect on the turbo, I am sure that some of the guru's on here can answer this one.

Cheers

Dave

Disco, what you have described is usually caused by inadequate oil return or excessive oil pressure. When you say the crankcase breather is as per na, does this mean that it returns to your inlet manifold.

You didn't tap into the alternator vac pump oil return line for the oil drain out of the turbo did you? That is most likely the reason if you did, the 1 oil line can't cope with both return oil volumes and causes flooding back into the compressor housing, simulating a blown shaft oil seal... You will need to have a seperate oil return for both alternator vac pump and turbocharger.

JC

rotating comp cover will not effect the oil side of things...whilst at it see how much sideways movement there is in the turbo (even though it was rebuilt) if there is to much then they leak...if there is heaps of oil there is a problem if there is only a little bit i wouldnt worry as i had the same problem and then was advised that some do leak whilst not under load so if there is only a little tiny bit i wouldnt worry too much...

A diesel doesnt have a butterfly in the inlet therefore there can be no vacumm! Thats why there is an exhauster on the alternator!

Originally Posted by davrac

If your air cleaner is completely blocked, I suppose that excess vacumm in the inlet could pull oil from the front turbo seal. Would need to be completely blocked and I can't say this is something that I have seen, interested to see if others have. Would imagine very low power and heaps of black smoke.

Can you clean the oil out and drive without the air filter in and see how that goes?

Cannot be a dry seal in the turbo as no rubber seals in there and rotating the housing will have no effect on the seals either.

Could it be that the turbo is just knackered? Is there much free play in the turbo main shaft when you lift it up and down.

Where is the crankcase breather plumbed in? If its in the inlet is it having oil dropped in front of the compressor wheel?

Is there a difference in the oil pressure on the nissan engine to the isuzu engine, not sure if this would have any effect on the turbo, I am sure that some of the guru's on here can answer this one.

Cheers

Dave

Originally Posted by landrover dave

A diesel doesnt have a butterfly in the inlet therefore there can be no vacumm! Thats why there is an exhauster on the alternator!

If the air filter is completely blocked you will get a massive vacuum. Sometimes enough to suck inlet hoses flat. Engine still has to try and pull the air from somewhere.

As already mentioned.

Check oil drain is large, free-flowing and above sump oil level.
Check supply pressure isn't too high.
Check air intake isn't vacuuming under boost.

Turbo seals and/or shaft play are almost never the problem.