Turbo or Piston?, Exhaust smoking.

[PAULJ5555]

The car does not smoke from cold but when it starts to warm up it smokes when revved, took it for a drive and the car boosts fine lots of power and drives well. When driving it smokes and when I put my foot down it leaves a big oily cloud not a big white cloud thou. When its hot it smokes ticking over and more when revved.

There is a coating of oil in the turbo pipes/intercooler but I think this is fairly normal looks like old oil, the turbo shaft is solid no play.

No smoke on cold start up should say that the valve stem seals are ok I think.

No mayo in the water or oil should say head gasket is ok.

The car is an MR2 Turbo 90K miles

What do you think?

[SuperchargedVR6]

Could be the turbine seal. Oil in the intake / IC is normal if PCV gases are routed back into the intake upstream of the compressor.

[terrybourne]

I concur with supercharegedvr6 on the diagnosis of turbo seals, but with smoking at increased temperatures only this would suggest that it could also be the piston rings that have failed due to ware or detonation. Another diagnosis is that it could simply be that your engine is running to rich at higher temperatures, which could be due to the temperature correction parameters on your ECU not being set correctly.

ETA

Please do not conduct business on the forums.

Edited by Big Al. on Friday 10th August 20:24

[lexusboy]

Very common for turbine seals to wear and allow oil through

[powerstroke]

lexusboy said:

Very common for turbine seals to wear and allow oil through

Yes sounds like this to me , could check the PCV and its pipes incase its building up crankcase presure which could cause oil to be forced past the seals.

[GavinPearson]

Check the turbo oil drain for coking. Poor draining may result in extra discharge through the shaft seals.

[PAULJ5555]

GavinPearson said:

Check the turbo oil drain for coking. Poor draining may result in extra discharge through the shaft seals.

Is this the silver pipe connected under the turbo? I think its in and out bolted on as one fitting?

[GavinPearson]

PAULJ5555 said:

GavinPearson said:

Check the turbo oil drain for coking. Poor draining may result in extra discharge through the shaft seals.

Is this the silver pipe connected under the turbo? I think its in and out bolted on as one fitting?

Probably. I don't know your car, but this issue has been common on many turbo'd engines and is cheap to fix. The pipe needs to be clean regardless, so remove, clean & replace.

I would also remove the intercooler & pipework & give them a really good internal clean. Use a solvent like gunk with a bottle brush, it will remove oil and can then be rinsed out. You may need to do this multiple times to clean the intercooler matrix of oil. After doing this wash the pipes in a high detergent solution to remove all of the solvent.

Carburettor cleaner is typically very good at removing oil from turbos so clean the compressor & compressor housing.

If you have removed all of the oil then all you have to do is run the engine for a short while and inspect the parts again. It should be very clear as to where the source of the problem is and you can then make an informed decision on what to do about it without getting into swapping numerous expensive parts.

[PAULJ5555]

GavinPearson said:

robably. I don't know your car, but this issue has been common on many turbo'd engines and is cheap to fix. The pipe needs to be clean regardless, so remove, clean & replace.

I would also remove the intercooler & pipework & give them a really good internal clean. Use a solvent like gunk with a bottle brush, it will remove oil and can then be rinsed out. You may need to do this multiple times to clean the intercooler matrix of oil. After doing this wash the pipes in a high detergent solution to remove all of the solvent.

Carburettor cleaner is typically very good at removing oil from turbos so clean the compressor & compressor housing.

If you have removed all of the oil then all you have to do is run the engine for a short while and inspect the parts again. It should be very clear as to where the source of the problem is and you can then make an informed decision on what to do about it without getting into swapping numerous expensive parts.

Thanks thats good advice, would an engine flush help the oil feed pipes to the turbo as they are very hard to get to/off.

Also how would I tell if the oil rings are worn/damaged? As there are oil rings and also compression rings on a piston. The car does not lack power so the compression rings are ok I assume but could the oil ring be a problem.

What test would show this? a compression/leak down test would just show the compression rings no?

[GavinPearson]

PAULJ5555 said:

Thanks thats good advice, would an engine flush help the oil feed pipes to the turbo as they are very hard to get to/off.

Also how would I tell if the oil rings are worn/damaged? As there are oil rings and also compression rings on a piston. The car does not lack power so the compression rings are ok I assume but could the oil ring be a problem.

What test would show this? a compression/leak down test would just show the compression rings no?

A good engine flush would help remove the gunk in the pipes, but if they are very restricted that may not be enough to do the job.

If the engine passes a leakdown test then the likelihood is that the oil rings are not worn either. You could use a borescope to inspect the valve stems for excessive oil.

[Megaflow]

PAULJ5555 said:

Thanks thats good advice, would an engine flush help the oil feed pipes to the turbo as they are very hard to get to/off.

Also how would I tell if the oil rings are worn/damaged? As there are oil rings and also compression rings on a piston. The car does not lack power so the compression rings are ok I assume but could the oil ring be a problem.

What test would show this? a compression/leak down test would just show the compression rings no?

A compression test on a hot engine with a wide open throttle. All cylinders should be within 10% of each other, if a cylinder is a little low, try putting a teaspoon of oil in the bore, if the reading improves its bore/ring wear, it's it doesn't it's valve wear.

[PAULJ5555]

Megaflow said:

PAULJ5555 said:

Thanks thats good advice, would an engine flush help the oil feed pipes to the turbo as they are very hard to get to/off.

Also how would I tell if the oil rings are worn/damaged? As there are oil rings and also compression rings on a piston. The car does not lack power so the compression rings are ok I assume but could the oil ring be a problem.

What test would show this? a compression/leak down test would just show the compression rings no?

A compression test on a hot engine with a wide open throttle. All cylinders should be within 10% of each other, if a cylinder is a little low, try putting a teaspoon of oil in the bore, if the reading improves its bore/ring wear, it's it doesn't it's valve wear.

But could I have good compression from the compression rings and oil still being burnt from bad oil rings that I assume would not be part of the compression test?

[Megaflow]

Theoretically, I suppose you could. But that would be a specific failure of an oil control ring, the only way to identify that would be strip and inspect. Generally, when you start burning oil past the rings it is slight bore wear, so they all start to leak.

[Mr2Mike]

Has the boost been wound up? It's not difficult to damage cast pistons through detonation. My Fiat Coupe had similar symptoms, it used to smoke pretty badly under any significant boost and it was down to piston damage on one cylinder caused by the previous owner playing with a boost controller and being clueless.