Black Spots on Tailgate

[Barracuda]

Can I ask what fuel you use and where from?

I only ever touch BP Ultimate 98.

[nomadx38]

I know my Deathlad lives out in the country but what about you lukepolo?

My only thought is that becuase of the hotter/dryer weather out in the country it runs richer (which is normal) and creates extra carbon (again normal).

The thing is out in the country the nights get very cold and quickly which could create a lot of condensation in the exhaust which when turning it on and then doing speeds of 100k/h might be enough to flick it up over the back.

The fact that the oil level is not going down is a good sign. The Only other thing I can think of is bad/fowled up injectors or ignition system creating a poor burn.

I would clean it and just keep an eye on it in different conditions and see what happens. Has it always done it or just periodic?

[gavs]

If its just carbon gavs, and doesn't smear, is this just normal waste from the combustion cycle? Or are there other factors at play?

Yes, hence the colour of the exhaust pipes however, there is a good chance that you should take it as a sign to open it up and rev it out a bit more

If it's smearing 'like nutella' rather than like a black water colour paint, this would lead me to think that some intake tract sludge is getting pulled into the combustion chanber and fired out the back. That's a problem with direct injection vehicles, there is no fuel passing through the intake tract to wash the carbon and blow-by deposits out. This is why it is so bloody important to use the correct 504/507 oils, not the 502 which you can use for top ups. 502 oils just don't have the same detergent-like capabilities of the 504/507 oils.

If my memory serves me correctly, I vaguely remember a couple of other 77tsi owners having this issue maybe 18-24 months ago and the dealers did a strip-down and full de-carbonisation clean on the engine....

[LukePolo]

I know my Deathlad lives out in the country but what about you lukepolo?

My only thought is that becuase of the hotter/dryer weather out in the country it runs richer (which is normal) and creates extra carbon (again normal).

The thing is out in the country the nights get very cold and quickly which could create a lot of condensation in the exhaust which when turning it on and then doing speeds of 100k/h might be enough to flick it up over the back.

The fact that the oil level is not going down is a good sign. The Only other thing I can think of is bad/fowled up injectors or ignition system creating a poor burn.

I would clean it and just keep an eye on it in different conditions and see what happens. Has it always done it or just periodic?

I live out in Penrith and the car is garaged every night. i also make sure no water goes up the exhaust when washing.

It's always done it, which pains me, I'm Mr. OCD-clean.

[LukePolo]

Yes, hence the colour of the exhaust pipes however, there is a good chance that you should take it as a sign to open it up and rev it out a bit more

If it's smearing 'like nutella' rather than like a black water colour paint, this would lead me to think that some intake tract sludge is getting pulled into the combustion chanber and fired out the back. That's a problem with direct injection vehicles, there is no fuel passing through the intake tract to wash the carbon and blow-by deposits out. This is why it is so bloody important to use the correct 504/507 oils, not the 502 which you can use for top ups. 502 oils just don't have the same detergent-like capabilities of the 504/507 oils.

If my memory serves me correctly, I vaguely remember a couple of other 77tsi owners having this issue maybe 18-24 months ago and the dealers did a strip-down and full de-carbonisation clean on the engine....

I've never have had to top up my oil before.. I'm going to pay another visit to Trivett this afternoon..

[LukePolo]

UPDATE: booked in at Trivett VW at the earliest date (4th November)

The guy tried to initially say that due to a higher back pressure? (wtf) there is more carbon thrown out the exhaust and that it is perfectly normal. I had to convince the guy to book it in for the day and get it checked.

[AndrewBurns]

It rained this afternoon and the water must have collected all the fine soot particles on the back of my car because now it looks like I reversed hard into an oil refinery...

Imagine this but instead of Daniel Day Lewis' face it's the back of my GTI

[car_nut]

It rained this afternoon and the water must have collected all the fine soot particles on the back of my car because now it looks like I reversed hard into an oil refinery...

Imagine this but instead of Daniel Day Lewis' face it's the back of my GTI

Rained here in Adelaide today and the back of my GTI looked, I expect, exactly like yours. I have had soot issue from day one, regardless of how I drive it, where I drive it and whether I use Caltex, Shell or BP (all 98 of course). Oil consumption is not an issue - after 2500ks the level has just reached the top of the cross hatch area from about 3mm above it when new.

I'm fanatical about keeping it clean so it's a slight annoyance. I will ask 'transporter' Miro's opinion when he fits Eibach (VWR) springs to my car in 3 weeks time. I asked an experienced performance exhaust shop owner about the soot when he fitted my Milltek - he ran his finger over the old exhaust pipe and said the colour showed a dark brown tinge, was not oily, so was nothing to worry about.

Andrew, have you questioned VW on your soot issue?

[AndrewBurns]

No I've only had it a few months (up to ~4000 km now). Like you at ~2500km the oil had reached the top of the cross-hatched area and now at 4000 it's down by two notches, so not really a problem with excessive oil consumption. I've run my finger around the inside of the exhaust pipe and the black stuff isn't oily so I think it's soot from the engine.

I'll mention it when I take it in for an oil change (probably at around 7500 km) but seeing as it's not excessively chewing oil and my fuel economy seems to be ok it's not really a problem, other than making the car dirty pretty rapidly. It's made worse by the flat back, I have pretty dark window tint and it's amazing how fast dust collects on the back window because of the suction-zone there.

[LukePolo]

It rained this afternoon and the water must have collected all the fine soot particles on the back of my car because now it looks like I reversed hard into an oil refinery...

Imagine this but instead of Daniel Day Lewis' face it's the back of my GTI

Yep, i hear ya

[LukePolo]

That's oily carbon if it smears like that. I'd be asking for what they supposedly diagnose it as in writing and signed by the service manager and dealer principle, then see if they play ball...

My Polo went in today for inspection and some tested, all tests returned that the car was manufacturer spec.

The service manager said that it has happened because the rings haven't settled? And that it was just heavy soot.

I was advised to drive it harder than I normally do.

The service manager also signed off on the completed service document to say that this was the problem.

I guess I just have to live with my Dalmation, washing it every 4 days. Dirty dog of a car. Unless you guys on here can advise anything that I can do myself to help prevent the soot spots??

On another note, I really didn't want to give the demo car back to them either, I was given a 110TDI golf highline for the day.. Gorgeous car.

[nomadx38]

Umm I would like to join this "soot club". Normally I wouldn't have a problem with soot but after going on the Victorian cruise on Sunday I found the entire back of my car covered in soot - some pretty large chunks as well.

The entirety of the time the engine was averaging 3000rpm so I guess the exhaust would have gotten pretty hot which maybe caused old carbon on the pipe to burn and break away...? Not sure but yeah it's definitely there - not oily though, in fact its so hard it's almost as if it's slightly burnt into the paint.

Also it was interesting to note that the exhaust tip was completely black which again never happens. We went up to the mountains where the temp dropped to 3 deg and the idle went up 100rpm so I guess it was slightly running rich.

In any case I guess you guys with soot problems are actually driving them and really heating up that exhaust