Ignition Coil Lifespan

RickG · Post by **RickG** » 02 Apr 2018, 05:42

After reading a couple of recent posts involving engine coils, I'm curious ... what is the lifespan of these coils?

I don't see anywhere in the car's maintenance schedule (2007 V70 2.5T) where they are replaced, even during a major service.

Is it a waste of money to proactively swap when spark plugs are replaced?

Thanks -

Post by **oragex** » 02 Apr 2018, 06:20

Very long. I'm sure many cars went to the junkyard with most in not all of their original ones. At least that's what I see when I go there. Yes, not only a waste of money, but more importantly, a problem when replaced with aftermarket parts. Better keep one from the junkyard/Ebay, but replace the spark plugs with OEM ones.

Most likely the wires to the coils may get damaged.

When a coil fails it usually acts as missfire under acceleration and it's usually only one in cause.

Post by **June** » 02 Apr 2018, 06:23

My 2004 at 157K has originally installed coils working just fine. I understand incorrectly gapped plugs cause failures. My car is serviced by the dealer and plugs replaced every 60K per maintenance schedule. So why replace them? June

Post by **cn90** » 02 Apr 2018, 08:20

- Failure is from insulation on the outside of the winding going bad. A function of age and heat.

- Get some used OEM coils at local junk yards for cheap and keep them in the trunk for emergency.

Post by **abscate** » 02 Apr 2018, 09:31

If you want a trouble-free car, replace at 100k miles, 10 years.

Buy 5 Bosch from FCP, sell the 4 as tested spares, keep 1 to replace while you replace the failed one with lifetime warranty.

If you want to maintain to failure - buy a spare, replace as they fail. Works poorly when SWMBO is in MD with a coil failure and you are in the Negev getting shot at by the ISL Air Force.

Ill SWAG the MTBF as 150k miles. We lost one at 120kmiles on the 1999 after a high voltage starter pack jump - my conjecture.

jbeebo · Post by **jbeebo** » 02 Apr 2018, 11:24

180k miles now, had one coil pack failure @ 165k. Remaining 4 are factory original. I'm of the approach of replace them as they fail vs. proactive bulk replacement. But I could see the argument for increased availability afforded by a proactive approach.

Post by **Rattnalle** » 02 Apr 2018, 11:48

There's no sense in replacing them all just in case since they usually last the life of the car. Getting one as a spare is perhaps more sensible but how many spares is it reasonable to haul around just in case? I'm going with none apart from the spare wheel and on the 5000 km summer road trips an extra litre of oil.

Post by **abscate** » 02 Apr 2018, 11:51

I had one fail on the 1999 at 120k miles, 10 years

Two fail on the 2005 at 10 years, 100k miles.

Post by **mrbrian200** » 02 Apr 2018, 14:02

I thought these CPs were known to have a predictable drop in spark intensity as they age. Or is that 'marketing' circulated by retailers trying to sell you something you don't need?

Post by **abscate** » 02 Apr 2018, 14:10

There was a recent thread where someone claimed they adjusted voltage/current to the coil as they aged. Ive found no evidence of that, and in fact I believe the 12V supply is direct B+ via relay, so that would require adjustment of the shut off time in the ECM...again, never read this anywhere else.