Hi all,
I suspect that my turbo is slightly blowing oil into the compressor side of the turbo, towards the intercooler (1.6HDi; 90bph; 2007; M59; no dpf/fap; ~93,000k miles; DV6ATED4; 9HXC engine).
There has always been a little bit of oil in the air intake (pre-turbo) and comparing to photos of other people, it seemed normal. I would not have noticed, but I installed an oil catch can and all the air intake pipes are clean. I took the air intake pipes yesterday and there is a bit of oil sprayed in the air intake pipe, just before the turbo. Crucially, only there, like the turbo when spinning has sprayed a bit of oil. The rest of the pipes are spotless, from the oil catch can to air intake, no oil whatsoever.
I took the rubber connection (from turbo to intercooler) just connecting to the input for the intercooler and there are a few drops of oil there. I had cleaned the intercooler before (~2 weeks ago) and cleaned that one, so I know it is new oil.
The car does not consume oil in between oil changes, so not really that much of a problem, but still.
AFAIK, there are several reasons why the turbo would blow oil pass the rubber o-ring (compressor side of turbo). Not in order of significance or likelihood to have happened.
1. Oil return pipe (the big fat rubber tube under the turbo) is somewhat blocked or kinked.
Thus, the turbo cartridge gets compressed with oil, but slow to return, hence an increased pressure and leakage. Does not seem like it. I have not removed it to check, but there is no kink in the hose. It is pretty fat pipe, so unlikely to get blocked. It is a stock turbo + pipe, so unlikely that it has been previously rebuilt and RTV silicone put on the return seal to block the exit.
2. Knackered turbo cartridge.
I already checked the play in the turbo shaft and it is pretty normal. On cold turbo there is a minimal play (radial; left-right, up-down) and no axial play (in-out). On warm engine/turbo, there is no play whatsoever, so the shaft gets sealed pretty good with the oil. So, cartridge is likely to be in a fairly good state.
3. Overfilling of oil.
The return turbo oil feed pipe cannot quite return oil fast enough resulting in an increased pressure. I ruled that one out, as the oil is ~3/4 full, i.e. 3 bars below max on dipstick.
4. Increased crankcase pressure, e.g. blow-by.
So, crankcase is under excessive pressure and oil gets returned to the turbo return pipe or cannot return oil as easily and results in an increased pressure in the turbo cartridge. AFAIK, this is probably more of a cause for ball-bearing turbos.
That is difficult to rule out. I already asked if anyone knew the reference values for the crankcase pressure of a new engine. Unfortunately, nobody seems to know. Saw somewhere that it has to be <50mbar. I measured mine and it is ~1.37mbar, so pretty minimal. I measured this before and after oil catch can, not really any measurable difference. I might have to fit a probe on the oil filler cap and measure long-term under load for a week.
The PCV or more correctly CCV (CrankCase Ventilation) valve can be blocked and hence increasing the crankcase pressure. I have already replaced the membrane and since there is a minimal crankcase pressure, that is unlikely to be the cause. Let's say the oil filler cap does not get blown out when opened and the flow of air from oil filler cap is pretty insignificant.
5. All turbos might blow some oil on the compressor side.
I doubt that. A turbo should not do that, otherwise you get oil in the intercooler and reduced air cooling efficiency.
6. Age + compressor side o-ring.
My car is ~92,000k miles, so the rubber o-ring (compressor side) might have perished a bit and hence passing some oil under pressure. That is possible. I have a slight blue-ish smoke on startup and I thought it might be valve stem seals, but it is possible that the oil gets pooled in the intercooler and/or other places and gets blown in on cold startup. Once the turbo gets hot the seals compress better and the smoking stops. If the compressor side o-ring was somewhat past its best, then it should smoke blue under load, not just on startup. There is no blue smoke under load.
So, are there any other possible causes?
The way I see it, it is probably N:6. I can potentially get a rebuild kit with o-rings and rebuild the turbo or I can get a new cartridge and again rebuild the turbo. Both do not seem too expensive from reputable sources, not the cheap Chinese versions.
Any ideas are more than welcome and apologies for the long post.
Cheers,
saskak
I suspect that my turbo is slightly blowing oil into the compressor side of the turbo, towards the intercooler (1.6HDi; 90bph; 2007; M59; no dpf/fap; ~93,000k miles; DV6ATED4; 9HXC engine).
There has always been a little bit of oil in the air intake (pre-turbo) and comparing to photos of other people, it seemed normal. I would not have noticed, but I installed an oil catch can and all the air intake pipes are clean. I took the air intake pipes yesterday and there is a bit of oil sprayed in the air intake pipe, just before the turbo. Crucially, only there, like the turbo when spinning has sprayed a bit of oil. The rest of the pipes are spotless, from the oil catch can to air intake, no oil whatsoever.
I took the rubber connection (from turbo to intercooler) just connecting to the input for the intercooler and there are a few drops of oil there. I had cleaned the intercooler before (~2 weeks ago) and cleaned that one, so I know it is new oil.
The car does not consume oil in between oil changes, so not really that much of a problem, but still.
AFAIK, there are several reasons why the turbo would blow oil pass the rubber o-ring (compressor side of turbo). Not in order of significance or likelihood to have happened.
1. Oil return pipe (the big fat rubber tube under the turbo) is somewhat blocked or kinked.
Thus, the turbo cartridge gets compressed with oil, but slow to return, hence an increased pressure and leakage. Does not seem like it. I have not removed it to check, but there is no kink in the hose. It is pretty fat pipe, so unlikely to get blocked. It is a stock turbo + pipe, so unlikely that it has been previously rebuilt and RTV silicone put on the return seal to block the exit.
2. Knackered turbo cartridge.
I already checked the play in the turbo shaft and it is pretty normal. On cold turbo there is a minimal play (radial; left-right, up-down) and no axial play (in-out). On warm engine/turbo, there is no play whatsoever, so the shaft gets sealed pretty good with the oil. So, cartridge is likely to be in a fairly good state.
3. Overfilling of oil.
The return turbo oil feed pipe cannot quite return oil fast enough resulting in an increased pressure. I ruled that one out, as the oil is ~3/4 full, i.e. 3 bars below max on dipstick.
4. Increased crankcase pressure, e.g. blow-by.
So, crankcase is under excessive pressure and oil gets returned to the turbo return pipe or cannot return oil as easily and results in an increased pressure in the turbo cartridge. AFAIK, this is probably more of a cause for ball-bearing turbos.
That is difficult to rule out. I already asked if anyone knew the reference values for the crankcase pressure of a new engine. Unfortunately, nobody seems to know. Saw somewhere that it has to be <50mbar. I measured mine and it is ~1.37mbar, so pretty minimal. I measured this before and after oil catch can, not really any measurable difference. I might have to fit a probe on the oil filler cap and measure long-term under load for a week.
The PCV or more correctly CCV (CrankCase Ventilation) valve can be blocked and hence increasing the crankcase pressure. I have already replaced the membrane and since there is a minimal crankcase pressure, that is unlikely to be the cause. Let's say the oil filler cap does not get blown out when opened and the flow of air from oil filler cap is pretty insignificant.
5. All turbos might blow some oil on the compressor side.
I doubt that. A turbo should not do that, otherwise you get oil in the intercooler and reduced air cooling efficiency.
6. Age + compressor side o-ring.
My car is ~92,000k miles, so the rubber o-ring (compressor side) might have perished a bit and hence passing some oil under pressure. That is possible. I have a slight blue-ish smoke on startup and I thought it might be valve stem seals, but it is possible that the oil gets pooled in the intercooler and/or other places and gets blown in on cold startup. Once the turbo gets hot the seals compress better and the smoking stops. If the compressor side o-ring was somewhat past its best, then it should smoke blue under load, not just on startup. There is no blue smoke under load.
So, are there any other possible causes?
The way I see it, it is probably N:6. I can potentially get a rebuild kit with o-rings and rebuild the turbo or I can get a new cartridge and again rebuild the turbo. Both do not seem too expensive from reputable sources, not the cheap Chinese versions.
Any ideas are more than welcome and apologies for the long post.
Cheers,
saskak
smile, you are alive! Peugeot Partner Escapade (same as M59, but with offroady-ish look) 2007, 1.6HDi 92
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