Does my 2.5TDI EGR valve need replacing??

[omniquito]

Hi All,

I have a2.5TDI Allroad and have a few issues lately.

The car lost all power under 2500rpm and would "Knock" a little too, it would go well after 3000rpm but not before. The engine light came on too...

got it diagnosed and the EGR valve had stuck in position and then the ECU had faulted it and although it freed up shortly after the ECU disabled control of it and thus it required a reset. All was fine after that.

Then... I noticed a little carbon deposit from the 3 holes of the EGR valve which the garage said was OK as a little exhaust was escaping past the seal...

Now...There is a lot of carbon depositting itself from the holes, far more than ever before and it is getting worse. Together with the very gradual power loss around the 2000rpm range, slight knock and what feels like lag.

My thoughts are that if the exhaust is leaking past the valve more and more then (I presume its a diaphragm??) is less effective and thus functioning later and thus causing the lag in valve movement and the symptoms....

Sorry for the long text but what is your opinion??

Finally, I have a quote of £81 for a new valve which I am happy with, but is there a guide to do this on a 2.5 TDI anywhere?? a couple of the bolts look pretty tucked away...

Thanks in advance and for reading! lol

Neil.

[Crasher]

It certainly looks as though it needs replacing and it is quite easy to do but don’t forget all the gaskets you will need.

[omniquito]

Hi Folks,

Just to finish this thread in case anyone searches it and wants to know the outcome....

With great thanks to CRASHER who helped me out no end on this...

The answer was YES the EGR valve did need replacing.
With all of the problems and symptoms that I wrote in my first post it all was cured when I replaced the EGR valve for a new part.

I ummed and arrrrd about having it fitted and got a very good quote from my trusted local VAG specialist of about £170 all in, valve at £100 and 70 labour....

Now after checking it out I decided to go for it myself....

EuroCarParts gave me the valve for £75 all in (incl some discount thru my work)

Removed the turbo heatshield (3 x 10mm head bolts) dead easy, 6mm allen key on the two horizontal bolts and 13mm (1/2") bolts up from underneath.

Now the 2 x 13mm bolts were quite difficult, I used a snap-on "crows foot" (not sure if this is the right term) on an extension bar to get to the first one easily and the second (closest to the inlet manifold) was a bit of a pain as it was REALLY close to the manifold.

In the end I had to remove the other three bolts and put some light pressure on the valve to move it away from the manifold enough to get the crows foot on and crack it off.

fitted the valve with gaskets (came with the valve) in reverse order starting with the problem bolt, job done!!

Took about 1Hr 20 and 20mins was dedicated to magnetising a 1/4 extension bar to fish out a bolt that I dropped in to V of the engine!!!!!

Lesson two - have a magnet on a stick to hand!! lol

Anyway, I hope this helps. It cured all of my power loss and hesitation issues and she is running like a dream!!! and saved £100!!!

Cheers and good luck, Neil.

[SiliconS]

Neil,
Thanks for following up with the solution to your problem. I may have the same situation with my '99 A6 2.5 TDI. I've just noticed spots of carbon on the manifold next to the EGR valve. Is this similar to the problem you noticed?



I've disconnected and plugged the vacuum hose for the moment but haven't had chance to see whether this changes the erratic performance and smoking of the engine.

I'd be grateful for any advice or info you can provide.

[omniquito]

Hi there,

I would say yes that is what I saw on my car, the patches got larger and larger and were also visible on the turbo heat shield aswell.

Not sure about the smoke tho as my car didnt smoke much anyway...

Also not sure what disconnecting it would do or not do to diagnose your problem as I didnt look into it?

My guide to removing them is slightly different in your case as I don't have those 3 pipes infront of the valve, not sure if this will make it any more difficult to do.

Good luck! Neil.

[SiliconS]

Thanks Neil.
Disconnecting the pipe seems to have improved the smoking but the engine's still not totally right so perhaps I need to replace the whole valve to satisfy the ECU and return everything to tip-top. I'll post again if it does in case it helps someone else...

[snapdragon]

Yes, the EGR is metered by the ECU looking for a dip in the air mass reading of the MAF (as inlet air is being substituted with exhauset smoke). Therefore, if the EGR has been disabled, it tends to throw a "MAF faulty" type code.