a6 2.5 oil problems

hi, my a6 started smoking, and got worse! road behind was invisible. oil smoke.so replaced turbo,. not problem, then had oil filter between cylinder banks cleaned. 15,000 miles later its doing it again. oil
smoke particularly on uphill starts, oil dripping from exhausts and oil up rear avant door. nobody seems to know why. can't drive, as hazard to others. like a mobile garden fire. any help please wits end isnt in it.
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Oil control rings on pistons have worn out. Major internal repair. Sorry.

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thanks for reply, its done 102,00, does 38mpg, and goes like a train, does this fit with oil control ring problem? Regal53 wrote:

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what is your total mileage...........
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hi, total mileage is 102,000. been one rich owner all services etc. i got it at 85,000. all oil changes etc.since. its 2.5 v6 diesel, 38 mpg average, runs brill, but then starts pumping oil into exhaust. thinking blocked breathers etc, any chance audi did recall and fitted bigger filters etc?
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102K is only a minor mileage for this model especially as regular servicing has taken place.
when you had the filters cleaned at 15,000 do we assume that cured the problem until now.
my only comment, looking through my a4 diesel manual, is that they make a clear point that heads and valves cannot be reworked on Diesels, only the valves lapped. By this I assume they are of minimal material thickness (in places) as we engineers put lack of material.
Perhaps something is occurring on a valve seat or between exhaust ports and oilways. But then again if it was OK after filter cleaning this would still show.
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thanks, got the feeling that its an engineered problem, due to design, rather than a fault. i'm hoping that enginewas not modified with different oil mist seperator and that this is the reason for pressuring u the crankcase oil. however, i dont really know what i'm talking about, but this seems possible. cheers
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hi, thanks for reply. yes problem seemed cured. it was some sort of an oil filter between the cylinder banks that was cleaned, perhaps this is the oil mist separator? after this it was great until suddenly clouds of smoke. i think its pressurising up and apparently it is a known problem on this engine. see below. thanks again
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Is the smoke black or blue ? If its black then you are overfueling. If it is blue then you are burning engine oil. Rgdss
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I don't know about diesels but black smoke could be fuel related, blue - oil related, try draining some engine oil down to the min mark on the dipstick & see what happens,
Steve.
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thanks, for this. its oil, in the sense that its dripping out of the exhausts. looks like its pressuring up. cheers
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John, for certain models there is a crankcase pressure check :
This must be performed for vehicles with engine AFB up to engine number 154 591 and AKN up to engine number 031 889.
If the pressure is too high then the oil-mist separator must be replaced. This may be the part that was cleaned in the past ??
Rgds
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hi, thanks for this.my engine fits the numbers. who does the crankase pressure check? what are the parameters. i plan to fit a new oil separator this time as my audi spares dept says they used to have this problem and this was a common cure. thanks again. got feeling its a design error rather than a fault,(great god audi will prob strike me down for saying it!). i suppose the trade expects audi to get it right and so looks for problems rather than design errors.
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Its a 40k miles service check. Pressure must be less than 5mbar at idle measured at the dipstick guide tube. Hope replacing the oil separator fixes it. Rgds Alec
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tremendous info, lets hope this sorts it, thanks again cheers john
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sorry to bother you again, alec, but have you any idea where this oil mist separator is to be found? mechanic who fitted turbo says they replaced something that could be it, that was located under the turbo and could only be got at with the turbo out. the audi garage spares service seem to think the separator is found next to the oil filter housing, although they say there diagrams are 2 dimensional and they don't really know. so it just gets more and more involved. any help please. cheers john
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Don't want to jump on this thread - but I think I had a similar problem .smoke at idle for me though (keep revs up above 1000rpm and no smoke) ....driving has no smoke / loss of power etc. No loss of water or noticeable oil.
Called audi dealer - their diagnosis over phone was that it was almost certainly blocked crankcase breather that needs a new filter fitting ...which sounded like it was in the same position that your audi parts think. I was old it was next to / under the oil filter ...but awkward to get at (3 hrs labour) as (I think) he said injector / diesel pump needed to come out. Basically if you take engine cover off it's in the middle of the V block...
The dealer told me I could diagnose by getting engine hot (it doesn't smoke from cold ). Dealer told me it wouldn't smoke after overnight as pressure build up can dissipate - but once up and running pressure builds up in crankcase...hence will smoke. So ..once hot / smoking ...remove engine oil cap and he said I would have hiss from cap due to presssure...sure enough I did ...and with cap off smoking stops....
Mine is 98 C5 A6 2.5 Tdi manual quattro - 118,000 miles - full audi service history every 10K - 38mpg average.
Hope that helps...
john wrote:

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