2010 Jetta SW fuel mileage down and black soot on back end of car

2010 Jetta Sport Wagon, DSG Transmission, 80,000 miles.

I recently had my turbo replaced and ever since, my fuel mileage has been down by 3-4 mpg and the back end of my car gets covered with black soot.

Also, it just started getting harder to start when cold. May take 10 seconds crank sometimes. Sometimes it will start and die right away. Once it's running, it runs fine with no noticeable loss of power.

The turbo was replaced because Jiffy Lube was using the wrong oil (505.00) and turbo had complete failure. Jiffy Lube paid for the new turbo Work was done in a shop of their choice but I know they used factory OEM part.

There are no error codes showing up on computer VCDS.

I don't know where to start. MAF, EGR, DPF??? Diesel is new to me. Bought the car used and have only had it about 1 yr.

Help!!

Jiffy lube? Oh boy...

Is the correct 507 oil in the car?

Yes, Correct oil 507.00 is now in the car. Won't make that mistake again.

Since you have a VCDS, I would be curious to see what the DPF ash load is. If the previous owner(s) used the wrong oil, it could get ugly.

Also, can you describe the turbo failure? Any idea how much oil was sent through the DPF? There should be no soot coming out the back.

Typically during a catastrophic turbo failure, a lot of oil is sent into the intercooler and down the exhaust. CRs are known for hydrolocking cylinders (and bending rods) after turbo failure due to the intercooler's outlet being on the lower edge of the IC, hence more prone to this type of collateral damage than earlier TDIs.

It sounds like the DPF is toast, but you might want to see if there's still a bunch of oil in the IC and perform a compression test to determine if you've got low comp on one or more holes.

Low comp will lead to loss of mileage, poor staring, as well as excessive soot after combustion, and could cause a premature failure of your new DPF.

Turbo failure was catastrophic with at least 2 quarts of oil going some place. The car went into limp mode then died when my wife pulled over and stopped. I did feel a hydraulic bang when I tried to restart the car. Yikes!! That's when I called the tow truck.

I know a lot of oil went into exhaust because it was dripping out of the tail pipe. I originally thought the soot was from residual oil in the exhaust system and thought it would eventually burn itself out, but not so.

I will test compression and take DPF readings tomorrow and post results.

I'll have to look up how to remove intercooler to check for residual oil.

Thanks for your help.

Tuco said:

Jiffy lube? Oh boy...
Is the correct 507 oil in the car?

Click to expand...

It is good to know that Jiffy Lube is standing behind this repair financially! To my knowledge this is not a data point we had previously. Back to the real question...

I would take the car back to Jiffy and explain that things are still not right. Try to get the contact information for the shop they used to do your repairs. Even if Jiffy won't step back up, the shop may help you and charge Jiffy.

Like the above post, I'd be screaming to get it fixed "RIGHT". Your car was A1 before the bad oil choice. It was "fixed", but still not "RIGHT".

My buddy's famous quote: anyone can change oil, but can they change it "RIGHT".

Advise, if you wan't to keep going to NON TDI guru places - bring your OWN OIL. These quick lube places should and do charge around 30-45$ if you bring YOUR supplies. Mr Lubes around me charge 30$. I pay 7$/1L for oil, and buy bulk VW filters at 7$/ea.

You can save a few bucks... but I tell ya.. when you deal with turbos, and minimum wage'd grease monkeys still in diapers working on your car ...

My high school's shop teacher's famous quote - Pay me now, Pay me later.

I feel bad for ya. Keep screaming and don't let them get away with wrecking your ride.

DPF Readings

OK, so far I've got the following information to add. The following readings taken with the engine off and key on. (Hope that is correct way to do it??)
Oil Ash Volume 90 ml
Soot Load(g) Calculated 5.1
Soot Load(g) Measured 0.0

I don't know what all of this means but there it is.

I will see if I can do a compression test with the equipment I have. If not I will wait until Monday, talk to Jiffy Lube, and take it back to their mechanic for compression test.

At 80K miles, a 90 mL ash volume is probably high - should be closer to 65 to 80 mL, but every car is different. I think the compression test will be most revealing.

compression test

I was unable to perform compression test today. I bought the tester from Harbor Freight Tools but it will not work on the 2010 Jetta. The glow plug holes are recessed to far to make the connection to the test tube with the provided 90 degree coupler. I will check in with Jiffy Lube monday morning and see what their response is.

Stay tuned. I appreciate the help and support!!

I think/fear that comp test is going to be the tell-all.

The CR comp tester is a pretty specialized tool and while it's becoming more common, is till going to be difficult to find in local stores. I was able to adapt this one to the tester I already had, but it's pretty pricey.

Note to self: If turbo ever goes bad, head to Jiffy-Lube, get an oil change (with inevitably wrong oil), drive for a bit, head back to Jiffy-Lube....

Jiffy lube sent me back to the shop that replaced the turbo. They did not have the tools to do a compression test and did not know what else to look at since there were no error codes showing up on the computer. Finally gave up and took it into the dealership today for diagnostic check.

Neither shop or dealer think it could be a bent rod since it's been driven 5000 miles since turbo replacement without blowing up and with no vibration. They are both leaning towards damage to DPF from oil running through it.

I will let you know what the dealer says as soon as I hear from them.

They need to do a comp test. I've seen 3 CR Jettas with blown turbos and bent rods. They all ran and drove, some better than others. I had one that was 110 psi low which is huge, but there's so much idle stabilization possible that only a savvy ear looking for an issue could hear it immediately after cold start.

Update

I got the car back from the dealer today. They replaced the intercooler, which had lots of oil in it, and de-carb'd the air intake, which was all carboned up. Also, they found that the coolant had been contaminated with oil and replaced the coolant and the coolant storage bottle.

They also found that the high pressure fuel pump was leaking and had to replace that. I don't believe the fuel pump is related to the turbo failure but probably contributed to the difficulty starting.

They indicated that it may still need a DPF and want me to come back in 30 days to evaluate.

Too soon to tell if the problem is fixed. Will monitor fuel milage and watch for soot and post results in a week or 2.

By the way, VW did not feel that there was any head gasket damage or compression or bent rod issues. They said that that would show up on the computer. Don't know why they are reluctant to do a compression test? If issue is not resolved, I will pursue further.

The invoice was sent to Jiffy Lube. Waiting for their comments.

get a compression test.

End of issue

Returned to dealer for final checkup. Soot has stopped. Fuel mileage is back to normal.
I asked them once again to do a compression test and they told me it was not necessary because the computer would notify you of a lean miss fire if compression was low in one cylinder. I have to believe them since everything is running fine now. I talked to both the mechanic and the service advisor.
Jiffy lube paid for the intercooler. I paid for everything else which was determined to be normal maintenance.
I don't know for sure what fixed the soot problem. It could have been the carbon build-up in the intake, the oil in the intercooler, or low fuel pressure from the leaking fuel pump.
I don't think it was the fuel pump because Im sure it was not leaking when I first got the car back from the shop that installed the turbo. I think it started leaking a couple of months after which is when I started noticing the longer start cranking time.
Bottom line is, the car is running fine now. Jiffy lube, in my town, is stocking the correct oil now but I don't think I will use them again. I do have to give them credit for standing behind their work and paying for the majority of the damages.
Until I find a good VW diesel shop, I will use the dealer for my oil changes.

You "don't think" you'll use jiffy lube again?

Your thread should be a sticky one man.




Glad your car is back on track. I think most of us feel bad for you and the ordeal you endured.

The cooling system contamination and intake cleaning should have been covered by jiffy lube IMO