Audi a3 constant spark plug failure

audi
a3

#1

Good Morning, I’m new to the site and hoping you guys can help me out if possible.

Last year my a3 (2006) needed new spark plugs fitting, I was idling in a safari park, engine warning light came on, went in to limp mode etc.
My local garage replaced them, job done. This was last august.

2 weeks ago same issue, was stuck ina traffic jam for about 2 hours barely moving and the engine started shaking, engine light came on but this time flashing and wasn’t sure if there was a brief smell of sulphur.

Took it back to the garage, spark plugs again, replaced under warranty. All sorted… so I thought

The garage also took a look at a power steering issue I have the next day, when finished I left the garage and the spark plug error came back!

They took another look and this time replaced the ignition coil, all sorted…

The power steering issue they couldn’t sort because of a sensor so I took it to another garage with a good rep for a 2nd opinion. Whilst the garage were sorting this out the engine warning light came on again!

They have said they have fixed this now with new spark plugs! I told them this was the 3rd time it had happened and if its likely to be anything more sinister, they said to leave it with them. I also mentioned when I was topping up my oil the other day I noticed a yellow residue in the oil filter cap and running down the side. Does this mean the head gasket has blown? There is no coolant leaking or oil, engine temperature normal.

I’m just at a loss at what it could be,

Anyone here have any suggestions?

Thanks again.


#2

We need a little more info, please. Did the mechanics show you the plugs? Are the spark plugs fouling (black lumpy tips)? Burning up (white blistering tips) ? Or just coming loose?

Yellow residue could just be moisture accumulating over time. How many miles (or km) are on this car? Are you watching the coolant level carefully? It doesn’t take much coolant through a blown head gasket to get moisture in the oil.

Knowing WHY the spark plug were replaced will help a lot in the diagnosis.


#3

The yellow residue could be from making a lot of short trips, especially in cold weather.
The oil doesn’t get hot enough to drive off moisture.
It could also be from a problem with the PCV system.
Has the PCV valve ever been replaced?
+1 to Mustangman: it’s essential to know just how the plugs are failing to make a diagnosis.


#4

Hi, thanks for both your swift replies.

Initial garage didn’t mention anything wrong wth them, just said they had failed.

The new garage said they spotted a bit of what they described as soot on them.

The coolant hasn’t been topped up for a while but hasn’t decreased at an alarming rate.

I do about a 20 min journey each way every day to work, but I have also recently driven nearly 200 miles in it with no problems so not sure about short journeys?

The only parts that’s have been changed in the past 12 months is the ignition coil and spark plugs.

Is it pure white residue if the head gasket has gone?

Thanks

Edit: there’s around 80,000 miles on the clock


#5

OK, based on that, the plugs would likley not come out sooty if the head gasket failed. Also based on your minimal coolant loss, I’d say a head gasket isn’t the issue but keep an eye on the coolant level, just in case. The residue on the oil filler cap could easily be 80K worth of buildup.

Back to the plugs. The type of sparkplug installed could be the issue. There are cars that are SO sensitive to sparkplugs that any brand different from the plugs Audi installed would throw a code. My 2001 Saab is like this. I did a google search and found this engine also has issues with ignition coils. There are 4 separate coils, one for each sparkplug. There have been several revisions to these coils over the years. Make sure your mechanic is using the sparkplugs the your owners manual calls for and not to use aftermarket (non Audi) coils. You can either go back to the original mechanic and keep haing them replace sparkplugs until they put in the right parts or go to an Audi specialist - either the dealer or an independent shop that specializes in Audis.

Good Luck


#6

I agree. Any spark plugs other than the ones recommended by the OEM are a gamble: a gamble with its downside heavily outweighing any possible upside.

Make sure, via owners manual or underhood sticker, which plugs your car needs.
If you can’t find the info there, use your VIN and ask an Audi dealership.


#7

Thanks for that, feeling a bit More reassured now.
The latest garage have said they sorted the misfire by changing spark plugs, maybe they have used the ones you suggest.

I’ll keep you updated and thanks again


#8

Any time I remove the plugs from a car, no matter the mileage, I always run a compression test just to make sure things are good mechanically.

A cylinder going down can cause premature plug failure is why I mention this. Generally speaking, the plug will soot up due to low compression.

The plugs are out anyway so why not kill that bird at the same time is the way I look at it.