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Author Topic: Blue/Grey smoke from exhaust, even when warmed up  (Read 626 times)

Offline OllieVRS

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Blue/Grey smoke from exhaust, even when warmed up
« on: November 20, 2021, 04:55:54 pm »
I have the worst luck when it comes to buying cars it seems. The car I've just spent 3 months on, 100 hours under the car and over a grand in parts (thread here: https://www.mk5golfgti.co.uk/forum/index.php/topic,132008.0.html) has just developed a second major issue. TFSI BWA engine.

Barely-blue grey smoke from the exhaust.

While fixing the oil pressure issue, I shrugged off the problem as simply moisture/steam as it was only during the cold start it was there. After hard driving it seemed to be gone (at least on idle anyway, there wasn't enough of it to see in the mirror either).

Now that I fixed the car, first I noticed that there was a oil-burning kind of smell every time I got out of the car after leaving it, and so I decided to check the oil level.

Over 100km of driving, it had lost approximately 500ml of oil, way above VW's specification. There is no visible oil drip from the car.


The car somehow passed emissions during the NCT (Ireland's MOT) when I put it through it on Wednesday.

The next day, after decelerating coming off a motorway and stopping at a roundabout, I noticed a small cloud of smoke catch up to me on the driver's side. This is when I decided I need to investigate.


I need to figure out if it's a blown turbo, or worse, valve stem seals. The latter would probably mean it's time for a replacement engine. I've invested so much time and money into this car already, just for it to let me down once more. :sad1:


Here are some videos of the smoke when revved:




I also got some pictures of piston 1 and 4 using my cheap endoscope. I know the photo quality is atrocious, but it was the best I could get. I can't tell if what I can see it oil or simply carbon build-up.

Piston 1:




Piston 4:




and also a picture of a leak I spotted on the turbo, I'm not sure if this indicates it's blown or not



As always, an input is appreciated  :smiley:
« Last Edit: November 20, 2021, 04:57:35 pm by OllieVRS »

Offline LC5F

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #1 on: November 20, 2021, 05:43:09 pm »
Sorry to hear the continued problems.

Could be turbo oil seal - check the inside of the intercooler pipe - there normally is some oil, but if there is excessive it points to oil seal on the cold side.
Next thing to check is turbo shaft for play - easiest side to get at is the hot side - undo the down pipe and have a feel for play in the turbo shaft.

My turbo was shot, I used  https://www.turborebuild.co.uk/webshop/ rebuilt it myself with a kit £22, it's surprisingly easy to rebuild - but I did send the rotor out for balancing £45+ postage - they spotted scoring in the turbine shaft, and replacement was £32.

Any leaks will be making the oil consumption seem worse, the last picture is the leak at the banjo is the turbo oil feed - try cleaning it off to see if it returns - but the oil on the left could be cam cover or leaking breather pipe.

Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #2 on: November 20, 2021, 07:26:50 pm »
Thanks for the reply @LC5F - I'll have a look on Monday at the intercooler pipe, and I'll see if I'm able to access the downpipe while only having two axle stands.

Were you getting similar smoke out your exhaust when your turbo was shot?

Offline LC5F

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #3 on: November 20, 2021, 08:13:37 pm »
No - but I could see a plume off stour when I booted it and had a good amount of oil in my intercooler.

All 4 downpipe nuts can be got off from up top, you are only needing to expose the hot side of the turbo, you don't need to remove the whole downpipe from the car.  Hardest is bottom one nearest the block - battery out and a few extensions in under the back of the head and it is just gettable from up top too - if you have penetration fluid start spraying the nuts now

Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #4 on: November 20, 2021, 09:41:58 pm »
Just back from spraying all 4 nuts/studs with the best penetrant I had, WD-40. Hopefully it does the trick  :happy2:

Also, I was wondering, can the turbo still be making normal power if it's seals are gone/leaking? I never noticed a lack of power at any stage when driving it in this "smokey" condition.

Offline LC5F

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #5 on: November 21, 2021, 02:23:58 pm »
No real drop in power, its just oil pushing past seals - but you haven't had the car long, so difficult to bench mark.
Hopefully this is the main problem and not valve seals.
Check the bottom intercooler pipe first if you have more than say a teaspoon of oil you can stop there and assume turbo seal blown.

Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #6 on: November 21, 2021, 05:40:55 pm »
That's good to know. I did previously drive a Volvo V50 1.8 petrol, so I think I'd be able to tell if it was driving like a naturally aspirated 2.0 car, but I wouldn't be certain though.

I just sprayed the turbo downpipe nuts with another layer of WD-40 in preparation for tomorrow, and while in there I had a look at the spark plugs to check for any fouling. 

Plug 1:



Plug 2:



Plug 3:



Plug 4:



Another picture of plug 4, because I thought it looked a bit suspicious:



And here's a chart (may be a bit outdated) of what they're supposed to look like. What do you guys think?



Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #7 on: November 22, 2021, 03:43:53 pm »
Apologies for any spelling/grammar errors, am writing this on mobile.

After an hour and a bit of swearing getting the 4 nuts off, I've gotten the downpipe off.

I can only reach the turbo shaft with the tip of my finger as there's not much space to get my hand in after moving the downpipe out of the way. But from I can tell there's very little play.







As you can see it's quite dirty but I can't tell if it's carbon or oil (or both).

I didn't have time to jack up the car and take the intercooler pipe completely off of the turbo but I did separate it at the bottom to half a quick look. It was dripped a few drops of oil as I was taking it apart (can be seen in the first pic).







And one of the downpipe bolts fell down somewhere in the engine bay as I was putting them back, so that's fun.


Offline LC5F

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #8 on: November 22, 2021, 05:51:35 pm »
it looks like the oil seal on the cold side has blown - the oil dripping outside the pipe is a give away suggests a seal is leaking too - then that puddle in the outlet pipe - suspect the bottom of your intercooler is filled with oil.
Little play means the turbo bearing is still good, but that would be replaced with rebuild.

If you decide to rebuild it yourself, I found the compressor wheel was glued onto the turbine shaft, needed heating to expand the alloy - difficult to keep aligned.
The CHRA cartridge has a peg to align the hot side to the manifold, mine was very tight fit and the peg stops any rotation, you need to wiggle it off the manifold.

Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #9 on: November 23, 2021, 08:55:56 pm »
Got some lovely pics of the turbo (cold side) today :smiley:






Also, I replaced the valve cover gasket which had about the same texture as dried glue. Took an hour of attacking it with a flat-head to dig out  :grin:

While replacing it I was also checking for cracks in the cover, but unfortunately found none.

So, back to the turbo. Tightened everything back up, and started the car. I ran straight to the back of the car to watch the exhaust's behavior.

No smoke for about 10 seconds, then back to the usual. Just as interestingly though, with the hood open (and at night with a head torch on) I could see there was some faint smoke coming from the back of the engine bay, a.k.a where the turbo is.


So it safe to assume it's the turbo causing the smoke?


I drove with quite a heavy foot back I was testing the oil pressure, so I may be part of the reason the smoke got worse  :innocent:

Also, just wanted to throw in a bonus problem the car has (of course my car has more problems :grin:) , timing belt gets a bit noisy when the car is warmed up. I changed it myself two months ago so it shouldn't be acting up so soon. It's tough to hear over the noisy alternator belt tensioner, but it's the low-pitched rumbling you can here at the end of the video.




« Last Edit: November 23, 2021, 11:07:46 pm by OllieVRS »

Offline Andy

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #10 on: November 24, 2021, 07:54:05 am »
Unfortunately that's  looking like turbo has gone 😕

Offline Pudding

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #11 on: November 24, 2021, 11:46:35 am »
I'll have a look at the pics later (work block image hosting sites) but 0.5L used over 100km sounds horrendous!  Was it that bad before all the oil pump shenanigans?


2007 ED30 | 2009 TDI 140

Offline Pudding

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #12 on: November 24, 2021, 07:02:50 pm »
The smoke looks like steam to me.  Was that from cold?  Smoke lingers in the air, whereas the 'smoke' from yours evaporates almost immediately, just like steam.

The oil in the boost pipes looks normal.  The rear PCV pipe dumps a load of PCV gases/oil vapour into the turbo cold side by design.

Oil leak on the turbo looks external, maybe from the oil feed line?  It does look like it's spraying out from there but I can't be sure.

Plugs look spot on.  Dry and the right colour.

God knows where 0.5L of oil went over 100km!  Are you sure the oil level didn't just settle after filling it up?  After draining the oil pump, sump and oil filter, it might take a little more oil to get it to max compared to a regular change.  If it really did use that much, there would either be a huge leak or plumes of smoke out the back.

How many miles on the engine?


2007 ED30 | 2009 TDI 140

Offline OllieVRS

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #13 on: November 24, 2021, 09:48:16 pm »
Thanks for the replies guys,

the mileage on the engine is 117k miles, but based on its history I can tell oil changes weren't frequent enough and also it's had low oil pressure in the past based on the scratches on the oil pump balance shaft sprocket.

It has to be oil smoke as the smoke is still there on idle after driving. You can smell the burnt oil after getting out of the car after driving it too. There are some small oil leaks but nothing that should cause such a drastic oil usage. I did a small blast on the local motorway towards the end of a 20 minute drive, where a cloud of smoke from my own car caught up to me when I stopped at the end a slip road coming off it. After driving the long even in cold weather, it definitely couldn't have been moisture.

I read somewhere that it takes the mk5 gti 10 seconds for the turbo to get oil pressure, and the smoke starts about 10 seconds after turning on the engine. The video I recorded is with the engine idling for over 20 minutes. The smoke disperses quickly because it's quite windy here at the minute.

I replaced the PCV when fixing the oil pressure, and now I have checked the valve cover for cracks and found none and also replaced its gasket.

Unfortunately I don't have the time or space to take the turbo out (8 hour job according to pelican guides) and combine that with 5 degree weather and rain.

I've gotten a quote of 700 euro to replace the turbo, labour included.
« Last Edit: November 25, 2021, 12:57:33 am by OllieVRS »

Offline Pudding

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Re: Blue/Grey smoke from exhaust, even when warmed up
« Reply #14 on: November 25, 2021, 11:20:15 am »
Ah OK, if you can smell burning oil, it's definitely shot then.

700 with labour sounds a bit on the cheap side.  Maybe they underquoted not realising how big a job it is!  A brand new turbo ranges from £750-£1000 in the aftermarket (BorgWarner reseller) and £1500ish from the stealer.  Recons range from £450-£600 for a decent job.  OEM Gaskets, nuts and studs come to about £70.

I recommend you replace the turbo oil feed and return lines whilst you're there.

Should feel like a new car afterwards with some added pep  :happy2:


2007 ED30 | 2009 TDI 140