2000 Jetta TDI - wastegate

#1

I have a 2000 Jetta with about 80k miles, bought used a year ago. The check engine light has been coming on. My mechanic says the wastegate is sticking but he got it working right; but then the check engine light came back on again. Mechanic got it working right again but says that next time he’ll have to replace the turbo ($1200) because the VW wastegate can’t be replaced separately from the whole turbo. Is that right?

#2

What kind of code (preferably by number,but I 'll take what you offer) directs you to a wastegate concern?

What sympton is your car showing?

#3

I agree with oldschool about needing info on codes and symptoms.

Here’s what the turbocharger looks like. Note the vacuum pod on the top left of the unit. That is what operates the waste gate and yes, it’s all one unit…
http://cgi.ebay.com/ebaymotors/Volkswagen-VW-Golf-Jetta-Beetle-TDI-NEW-Turbocharger_W0QQcmdZViewItemQQcategoryZ33742QQihZ020QQitemZ300281963605QQrdZ1QQsspagenameZWDVW

At this point the diagnosis sounds a bit odd to me.

#4

We don’t know the codes. I noticed what seemed like a loss of acceleration at some point, but after a couple of weeks I convinced myself that it was my imagination, possibly because of getting adjusted to it combined with my wife not agreeing with my perception. My mileage remained in the neighborhood of 48-50 consistently, so my concerns faded. At some point the “check engine” light came on, but it wasn’t always on, just most of the time. And it didn’t come on upon turning on the engine – it always turned on somewhere between 100 yards and 2 miles of driving. Then my mileage fell to around 44-45, which also coincided with fall temperatures arriving. As I was approaching inspection time, I decided to get the “check engine” light checked, not really thinking it would be a big deal (in the past on my gasoline cars this has always had something to do with the oxygen sensor in emissions control). So all I know is what my mechanic has told me, plus an advisory I’d gotten when I first bought the car to not let a mechanic replace the turbo (major bucks) when most of the time the problem is a much less expensive issue with the wastegate. If it’s not possible to replace the wastegate without replacing the whole turbo, why would I have been given this pointer? Anyway, the symptoms are as I described – loss of some pep, followed by periodic “check engine” light becoming more consistent and coming on shortly after driving rather than at start-up, followed by a 10% loss in mileage.

#5

Get the codes from the mechanic. It could actually be a control valve causing it instead.

If it is the turbo, you can get a rebuilt one significantly cheaper than that and say, two hours of labor. Shop around.

#6

I think he replaced another valve (N75 maybe? It was something 75) already as well - is that what you meant?

#7

Your mechanic is right in that the wastegate cannot be replaced separately from the turbo. It’s all one unit.
The N75 valve and the control valve are on in the same. If it’s been replaced, you can rule it out as the problem.
If in doubt, get a second opinion. And, as hallkbrdz says, a rebuilt turbo will save a bunch of $$.

#8

It would be interesting to examine this car. The loss of power could point to a wastegate stuck open but this would bring up the question of why the wastegate was open to begin with? Excessive RPMs?

A theory I’m batting around is that there could be a control problem issue with the hoses to the wastegate vacuum pod.
Vacuum being provided when it should not be maybe? This could pull the wastegate open and if a control was sticking vacuum may not be released, which would in turn cause the wastegate to hang open and not close.

This example is not related to a diesel or turbocharger but could illustrate what I mean.
Old VW Bus with dual carburetors and EGR valve equipped. This model bus uses a vacuum solenoid between the EGR valve and the vacuum source (the intake manifold).
The bus ran like a top but at times when the throttle was hit hard the engine would stumble and flat die on deceleration. An open EGR valve will cause an engine to do this but inspection of the EGR showed it was operating properly.

The EGR should ONLY open under acceleration and I discovered that the vacuum solenoid was providing vacuum to the EGR when it should BUT the valve would close off and maintain vacuum to the EGR at all times. Easy fix, but took a bit of fault tracing to find since it was erratic in nature.
As an analogy here, think of sucking on a soda straw, covering the end with your tongue, and removing the straw from the drink. Vacuum in the top of the straw will not allow the drink to run out even when removed from the cup.

JMHO, and this is a guess only, I think the problem is likely somewhere in the control system rather than the wastegate itself.
Hope some of this helps.

#9

Yes, the N75. So that’s not it. It could be the hose, but that’s easy to find and I would think he should have checked that already. I’d guess he tried applying pressure to the actuator directly and it is sticking again. Sounds like he tried and cleaned it, which sort of worked. Here is a good link I found for doing that:
http://forums.tdiclub.com/showthread.php?t=43356

If that was all done, it sounds like its time for a rebuilt turbo, sorry. 8-9 years for one isn’t that bad, are those mostly in-town miles?

#10

You got it. He replaced the N75, cleaned and tested all the hoses, and the wastegate had stuck again and then he cleaned it again and now it’s unstuck (until it sticks again, which I guess we’ll know when the check engine light comes back on). So if it comes to replacing the turbocharger, he was recommending a brand that he uses a lot, Garret (linked above in the ebay listing in an earlier reply) which he says costs new what a rebuilt VW brand costs (about $1200), and in the future would allow separate replacement of just the wastegate, if that ever became necessary again. But my biggest concern is gas mileage. Will that affect mpg as compared to a VW turbo?

BTW, to answer a question below, we don’t drive high RPM (never over 2500 even at 70 mph), and our driving is mostly highway. I don’t know how it was driven for its first 65k miles - I’ve had it for a year.

Thanks for everyone’s comments.