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November 22, 2009

Adventures in car maintenance, part 231.

Filed under: Cars,Diesel — chuck goolsbee @ 12:09 am

My daily driver is in need of a little TLC. The clutch is making an odd noise, and the CEL is on, with the car showing symptoms (again) of a clogged intake manifold and EGR. I figured I’d tackle those today. The clutch could be something simple as a good fluid flush (it has been way too long since I flushed the hydraulics in this car… (bad owner!) So since that job is easy I did it first. On the Jetta it is best to remove the entire air cleaner box to access the fluid reservoir and the clutch bleed screw. From there it is a very fast process…

The motive bleeder in action.
The motive bleeder in action.

I have a “power bleeder” which makes the job pretty easy, the greatest benefit being that I can do the job alone without somebody to pump the brake pedal. It uses air pressure to push fluid through the system. I sucked out as much old brake fluid from the reservoir as possible, using a turkey baster (one I bought JUST for car-maintenance!) Then I filled it with fresh Castrol LMA DOT 4, attached the bleeder to the reservoir, and poured the rest of the Castrol into the bleeder’s bottle. Next I use the hand pump atop the bleeder to raise the air pressure inside the bleeder to about 10 PSI, and then walk around the car with an old milk jug, a length of clear tubing, and an 11mm combination wrench to open the bleed screws.

The other end of the transaction, in this case the passenger side rear brake.
The other end of the transaction, in this case the passenger side rear brake.

Once the fresh clean fluid starts running through the bleed screw is closed and I move on to the next corner of the car. The last item is the clutch bleed screw which is in the engine compartment. I did the whole car in about 5 minutes once the fluid started flowing. I expected the old fluid to be really bad, but it was surprisingly clean given how long I let it run between changes!

Next up I took on the EGR and intake cleaning. It has been less than a year since I did this, which bothers me. It is a real PITA task with lots of stuff to pull of the car, and many fasteners in hard to reach places. The EGR is easy to open and look at early in the process, and sure enough it looked very sooty… but nowhere near as much as last time. As I progressed I discovered a cracked exhaust cooler feed pipe which may explain the car’s behavior more than a clog would.

The exhaust cooler feed pipe. In this photo it is completely broken, but when it was on the car it was just cracked. You can see the blackened area where the exhaust had leaked.
The exhaust cooler feed pipe. In this photo it is completely broken, but when it was on the car it was just cracked. You can see the blackened area where the exhaust had leaked.

I’ll have to buy another one, which likely will take a while to track down.

Meanwhile, I’m going to forge ahead and remove the intake and give it a good cleaning. While not as gummed up as last time it still could use a cleaning while I’m in there. I managed to get most of the way there today with only 5 more bolts to go to remove it.

The area where the work is taking place.
The area where the work is taking place.

I’ve highlighted in RED the intake manifold where the EGR pumps exhaust back into the engine’s intake. No the soot is not naturally pink, it just looks that way! To the left of it I’ve highlighted in ORANGE where that (now cracked) pipe routes.

I’ll update everyone as I progress.

6 Comments

  1. Do engines that predominantly run on biodiesel suffer greater incidences of this goonk, or is it just a feature of all VW diesels, irrespective of fuel?

    Comment by vrooomie — November 23, 2009 @ 10:36 am

  2. I think this particular issue is specific to the “A4” era (1997-2003) TDI engines, but is largely dependent upon fuel quality. It’s come up twice now in my engine, once when I ran it for a few months on (shhhh!) off-road Diesel from a decommissioned generator, and then recently on Biodiesel. That BioDiesel was made from crappy oil… when the economy took a dive last year restaurants did everything they could to cut costs and fryer oils were one place they did this, going from quality feedstocks like Canola to el cheapo generic veggie oil. Literally 3 months after my feedstock quality dropped I clogged up.

    I THOUGHT my intake was clogged this time based on how the car was driving. In fact it is still pretty open compared to the past two clogs. My power loss and CEL were now obviously coming from the cracked EGR cooler pipe, as when the EGR closed the fresh intake it was sucking through a leaky straw on the exhaust side. Unlike in the past where power was down almost all the time, recently it was only rarely, and wasn’t as bad as the past clogs. It all makes sense now that I have all the facts.

    The intake had SOME cruddy build-up on it and since I was already there I went ahead and cleaned it up real good.

    I stopped by a parts yard this morning and they should have a new pipe for me later today or tomorrow.

    Comment by chuck goolsbee — November 23, 2009 @ 11:43 am

  3. Chuck, I’m surprised you’ve had clogging issues. Common wisdom as I understand it is the VNT sticking and EGR/intake clogging issues are both more often found in babied cars – the shift at 2200 rpm crowd – and I’d hardly expect that from you. I put about 100,000 miles on my ’02 (purchased with 42k) and every time I peeked it was at least as clean as yours is now. I never ended up cleaning the intake on that car.

    Of course there are a couple other tricks to remediation, like using VAG-COM to change the EGR adaptation values to
    minimize it’s function, or getting a tune that disables it completely. I moved from the former option to the latter which may be why I only had the joy of really rooting around under the hood for my 80k timing belt.

    I do miss that car. If I’m ever rich I think I’ll make a hobby of throwing that engine in any vehicle that doesn’t run away. I’ll pick up another in a heartbeat if I regain a longer commute but for now the 6BT Cummins in the 97 Ram I traded the Jetta for suffices.

    Comment by MichaelM — December 5, 2009 @ 12:30 pm

  4. It turned out to be mostly the cracked EGR pipe that was causing the car to misbehave. That said, this is my commuter car and I rarely get a chance to rev it up a and “babying” it is practically dictated by the conditions I normally drive it in: namely Seattle traffic on Interstate 5.

    Comment by chuck goolsbee — December 5, 2009 @ 1:02 pm

  5. Fair enough. I think I read recently that you guys as a metro area “won” most congestion or longest commute time or worst rush hour traffic or something along those lines recently. My condolances.

    Comment by MichaelM — December 5, 2009 @ 3:41 pm

  6. Sounds about right!

    Comment by chuck goolsbee — December 5, 2009 @ 4:01 pm

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