I was asked to have a look at a 2006 MY 55 reg Mk5 GTI DSG that had broken down.
Owner had bought the car a few hours ago, stopped at the services for a few mins on the way home.
Got back in it, turned key and some white smoke with a strong smell "like burning hair" came out from the bonnet/wing gap on the offside.
Engine turned over but no ignition.
The AA were called and checked fuses and ran a diagnostic scan but nothing.
Car was recovered and I started by taking the cover off the engine (always fun)
This revealed the coils and all looked OK but the smell seemed to be coming from cylinder 1 (nearest to timing belt) which looked a lot cleaner than the others (more later).
On removing the plug to the coil the damage below was visible.
You can see the pin from the terminal 1 on the coil had welded itself to the plug with the heat
Unlike with Mk4 Golf based cars, coil failure on Mk5 seems very unusual but I did a bit of googling and found other cases, both of which had involved cars that had recently been picked up from dealers by their new owners.
http://www.golfgtiforum.co.uk/index.php?topic=135800.0http://www.golfgtiforum.co.uk/index.php?topic=125811.0This got me wondering if this was related, what could a dealer do that would cause this?
While working on this car I noticed it had a very clean engine bay and concluded that the dealer must have cleaned it up but didn't think the engine cover could let water get passed it. Then I noticed that the seal around the filler neck was resting on the rocker cover rather than being clipped on at the top of the filler which would let water right onto coil pack #1.
THis pic shows the proximity of cylinder 1 to the filler neck.
There was also evidence of corrosion on the coil pack body which pointed to water ingress, all other coils were nice and shiney.
So it doesn't seem to be a problem that will afflict all cars randomly but cars that are washed under the bonnet AND have this seal dislodged. It could take quite a few days for the problem to manifest itself after the engine is washed and could be OK until the engine gets really hot and things expand (as it would have done with this one parked up straight after a motorway run).
The downside of the more reliable coils is that when they do fail the resulting damage is far more significant and beyond the realms of a roadside repair.
Repair involves a new coil (considering the suspected cause doing all 4 would be unnecessary but if someone else is paying then it's worth a go...) and the loom components from VW. Haven't ordered the parts yet so don't know if coils have a different part number now, these originals were 07K 905 715
THis is another link to someone who suffered the same failure but no mention how long they had it
http://www.mk5golfgti.co.uk/forum/index.php/topic,9982.0.htmlI hope this may prevent someones pride and joy going up in smoke and also puts owners' minds at rest that theirs could at any time too.
