There has been an ignition coil recall. Was your car included? My 2003 was.

 

Did they replace your spark plugs at the time of the recall repair as part of the recall or no?

 

No.

 

Problem was resolved with new coils and spark plugs.

 

Glad you got sorted.

Thanks for coming back and letting us know - lots of people don't!

 

Sorry for bumping an old thread here chaps. But this seems to be an ongoing problem for me.

Plugs have been replaced, as have the coils. Yet with just over 1000km since the coil plugs were checked, my misfire returned.

I pulled the coils today and found thus...
http://www.clubtouareg.com/forums/attachment.php?attachmentid=161242&thumb=1
this was the worst one, but all coils had some amount of water and corrosion in them.

what's the dealio here? could this be coolant? it had a brownish tinge to it, but i thought maybe it was just water and the corrosion caused the discolouration?

if not, how the heck is water getting in? i haven't sprayed the engine or driven through any water deeper than a couple of inches.

background is i have had the car for about 10k, and the misfire caused by this issue is now a third time deal.

in addition, i've had the rear brake light warning for a while now and one of the globes was dead. i've since replaced both and all working including the led strip thing on top of the tailgate - still got the dang message on the display. the "joys" of an 04 egg i guess. getting rather sick of troubleshooting rather than driving the thing.

 

How does the rubber seal look on the plug? The part that plugs into the coil from the wiring harness. There should be no water inside the plug cavity like that.

If all else fails, smear some die-electric grease in there to protect the contacts and possibly seal the faulty plug seal.

 

I suspect you're right - i believe the water is getting in through the plug that the wiring goes into (no idea what this part is called) and then making its way down to the coil connector, corroding along the way.

I wonder if I can replace those plugs or if I'd need to replace the whole wiring loom?

Just guessing now - but the drain plug above the firewall was quite gunked up with debris. I'm wonder if in heavy rain it pools in there and then sloshes around as the car bumps around?

Other than that I'll see what I can do to make the existing plugs watertight...

 

The plug on the wiring harness side should also be sealed. You could probably replace the connector on the harness side, but the tools to do it would be kinda $$ for a one time deal. :- /

Another option would be to find a used harness and splice in a known good connector. Probably not an ideal option, though.

 

looks like i might be up for a new wiring loom. water inside the cabling and not sure how it got there. wondering if i should just cut my losses at this point..

 

I don't want to scare the pants off of you, but google "vw coolant migration" and do a little reading. It's a real thing that happens and coolant is forced into wiring and can ruin an entire harness. I've even heard of it getting to the instrument cluster and causing even more problems.

 

Interesting. The workshop I've been taking it to seem convinced it isn't coolant. But just checking the thing now after a drive, there is a couple of small patches of what i assume is coolant from near the back of the engine. Feels slippery.

The last time when i pulled the coils the moisture inside was definitely slippery. I reckon it is coolant working its way up through the wiring. I wonder if the harness can still be saved if I get the coolant leak fixed? She is running ok at the moment.

 

I guess the next question is finding the coolant leak. Water pump has been done recently. It appears to be dripping down from a couple of places towards the rear of the engine. I'll see if i can get it up on a hoist and have a proper look next weekend. Any ideas?? Been doing some forum searching and someone mentioned a flange at the back of the engine?