How often do coil packs fail?

longwalks1

We've had our Audi A4 3.0 (petrol) for 7 years now, and think it has a problem with 1, or 2 coil packs (same symptoms we've had previously). All 6 were replaced by Audi 5 years ago on a late callback (its a 2003 model, but when we called AA out they questioned it and got all 6 changed for free by the main dealer)

Are coil packs a service item? And if so, how often should they need replacing?

Thanks everyone

EdGasket

You generally only change them if they fail. I have 16, 17, and 18 year old cars with over 150K miles (170K in one case) all on original coil packs. You would start to see misfire or starting problems if one was going; possibly total failure of the engine to run. The design that has the coil packs sitting on top of the spark plugs are more prone to failure due to the engine heat.

The only possible exception is if you have a valuable car where you might want to replace the coil packs as a precautionary measure to prevent possible ecu damage where the ecu is hard to get hold of and ££££'s to replace.

longwalks1

Thanks Ed
its an old Audi, not worth a great deal but she still runs well (apart from right now)
Its had a slight flat spot under acceleration occasionally and last week she coughed and spluttered a bit after Id parked up and before turning her off, same symptoms as previously so hoping its just a coil pack or 2

Thanks for your reply

BeenThroughItAll

When were the spark plugs last changed, and what was used?


Incorrectly specified, or old plugs, would make the coils packs work harder which can precipitate failure.

longwalks1

BeenThroughItAll wrote: »

When were the spark plugs last changed, and what was used?


Incorrectly specified, or old plugs, would make the coils packs work harder which can precipitate failure.

Full service a year ago, the car only does 4k miles a year. Plugs were changed then with brand name ones from EuroCarParts (cant remember what they were though)

onomatopoeia99

I've had one (of six) replaced on my 17 year old car in the 13 years I've owned it. Currently at 120k miles.

forgotmyname

Define a full service though? Often a full service can be the oil and an air filter and little else.

Sister does a big mileage and even though she had covered 20k+ a year, 4 services later it still have the fuel filter that i fitted.

None of them had changed the fuel filter.

Sometimes they only replace the stuff if you ask them to.

custardy

IME they do seem shorter life'd on modern cars,or perhaps modern cars require a tighter tolerance on their performance.

reeac

An American friend has a Lexus SUV with around 150k on the clock. These cars are notoriously reliable but he's had problems with the coil packs

wolfehouse

I know next to nothing about cars but had a Honda jazz under 3 years old. Coil pack failed, replaced under warrantee (eventually), then a year later another failed.
The mechanic said that if one fails it puts a strain on the others so if it hadn't been a warrantee job they would have recommended I change them all at the same time.

Strider590

Coil pack failures may indicate improper spark gaps on the plugs.

For every 0.2mm of gap, the coil has to output an extra 5000 volts, and this can cause them to overheat.