Ignition coils - how long do they last, should they last, and why do they fail?

[gmushial]

This was triggered by the "which ignition coils to buy" thread - I like the idea of one ignition coil per cylinder: unlike a single coil system, with six, one can limp home if one fails, and likewise one should be getting a better spark by not having to share a single coil. My question(s) have to do with: how long do they last; how long should they last; why do some Z models seem to eat them while others don't etc. I have 160k miles on the '99 M52TUB25 and still have the original coils, and it idles as smooth as glass and runs without a stumble. I guess a related question would be: with the water pumps - at 60k miles one replaces them, simply given their history and the consequences of having one fail. With the coils, that's been the history in terms of how long they last and do people generally replace them before they fail? Or, do most replace them one at a time when they fail? Or, do most replace all six when they have the first failure, assuming the other five aren't far behind? Related: my impression from reading here for the last two years - it seems the M54 motors eat coils much more so than the M52, or even S5x motors [this observation might be wrong]. Are the M54 coils designed differently than the rest, ie, maybe less overdesign than the rest? Or, maybe somehow they are subjected to more heat, hence failing sooner? I would be interested in hearing other's thoughts and observations.
as always: many thanks,
greg

[lokijibber]

I'm pretty certain just about every S54 out there has had the coils replaced at one point. Most early on in their life as I believe there was a recall. Again, I'm not sure of this though, just going from memory (which gets spottier by the day).

[gmushial]

I'm pretty certain just about every S54 out there has had the coils replaced at one point. Most early on in their life as I believe there was a recall. Again, I'm not sure of this though, just going from memory (which gets spottier by the day).

I think I know that phenomena too well ;-) and I think I agree with you w/re the S54s, now that you point it out and I scratch the gray matter as bit. But even with the S54 coils - what was causing them to fail? Heat? Spark cycles (number thereof)? And what was failing - the dialectic/insulating layers? And is that mode of failure the same as what others are seeing on other coils?

[kobayashi]

The S54s had a "soft" recall for the defective Bremi coils. Dealerships were instructed to replace them with Bosch units.

[steve f]

My M54 has 220k miles and still has the original coils, so I can't confirm that motor has problems with coil failure. That said, I'll be watching this closely to see what others experiences and opinions are.

[Mpyre]

I have replace 2 of my 6 coils. One at a time on my S52 with 103K miles.

[dimm6]

My M54 has 220k miles and still has the original coils, so I can't confirm that motor has problems with coil failure. That said, I'll be watching this closely to see what others experiences and opinions are.

Im almost in the same boat as you. I'm at a little over 225k miles an never had a problem with them, nor have I ever had to change one.

Do new ones even make that much of a difference?

[gmushial]

Wow... looks like we need more people to chime in - at this point it almost looks random in terms of which fail and which run forever ???

[luciano136]

I still have the original coils. 88k mi on my '99 2.8. I don't recall them being a common failure (as opposed to the water pump for example).

[dougmcintyre]

The original coils have 128k on my 2000 S52.

[jajou318]

I know some coils in the HPF cars were getting quite hot and failing, they introduced a coil cover that drew in fresh air from the front grill.

[spacecowboy]

I replaced the 6 individual boots when I changed the plugs at 60,000 miles, but kept the original coil packs. There was a little bit of corrosion present on the old boots.

[f50nut]

I haven't personally replaced my coils, but the dealer maintenance record shows that they were replaced within the first 10k miles

[spacecowboy]

I now carry a spare with me at all time, in case I have to change one on the fly. If one craps out, you'll be in limp home mode at best. (More like flatbed mode.)

Did you ever own a VW? LOL

[scrap]

Did you ever own a VW? LOL

+1 My GTI liked to have a coil fail on roadtrips mostly. After losing one in east nowhere West Virginia I had a spare on me at all times. I have not seen any problems with my M54 in the short time I've had it. To my knowlege its the original coils as well with 72k on the engine.

[cleanerPA]

AFAIK from the maintenance history that I could deduce, my car is still on the original ignition coils- 98k. No issues so far (knock on wood).

[spacecowboy]

+1 My GTI liked to have a coil fail on roadtrips mostly. After losing one in east nowhere West Virginia I had a spare on me at all times. I have not seen any problems with my M54 in the short time I've had it. To my knowlege its the original coils as well with 72k on the engine.

I went through the arcing coilpack issue with the old 12v VR6 GTI. Decided I didn't like what the go to JB Cold Weld fix of that time looked like, so I experimented with using PlastiDip back in 2002. That was my contribution to the VW world. Properly thinned it looks OE when finished. I have never had an issue with the individual coilpacks on the VR-6 in the 2004 R32. The S52 coilpacks are still original, but the metal had started to oxidize inside the boots, so I replaced them as routine maintenance. Cheap insurance at, IIRC, $6 each.

[z3540i]

I believe (As with any electrical components) Its Heat the kills the coils....I feel like climate were u live & hwy driving (air flow)vs City (stagnant heat) & ever over heated the car all play a role in coil life....i left the covers off of my 540i bc i felt it let more hot air out and let air pass over them....im sure up north if you drive mainly hwy they last over 200k miles as many have seen....southern states were its 100 degrees and driving in the city...probably under 80k Miles

[mikey1951]

I had 2 Bremi coils fail @ 103K and replaced all 6 with Bosch. In Florida and garaged.

[gmushial]

I'm in Redding: so we get HOT - three months which can be over 110F, will be over 105F, and the hottest I've seen is 119F - so, plenty of heat, but 90% of the miles, though probably only 50% of the time, are freeway miles. 160k miles on a M52TUB25, original coils.

There are three other Z's in the area that I know of: a 1.9, 3.0 and 2.8 - will see if I can find out about their coil history/experience.

- - - Updated - - -

Does anyone know if the 1.9's share the same coils as the 6 cyl motors?

[steve f]

The 1.9 uses a coil pack and spark plug wires. I'm thinking I might upgrade the DASC to individual coils someday as a project...

Most if the miles on my M54 were in the central San Joaquin Valley. Very similar weather conditions as the northern Sacramento Valley. Maybe, not quite as extreme, but close.

[steve f]

Redding is very unusual in being 40deg north and so hot... but it has to do mostly with the 6k ft plateau surrounding the end of the valley: the air on the Modoc plateau gets headed into the 90's and then a north wind pushed it over the edge and down into Redding and Red Bluff, dropping 5500-6000ft heats it 15-20deg F... we generally match or even exceed Las Vegas temp-wise and they're 10deg further south and out in the desert. ... but hey: all that heat grows the sweetest melons and the best okra :-) and it makes for delightful top-down moon/star light drives with the wife, taking the longest possible way home from a dinner out :-)

Yep, it is a great area!!! and just a quick trip up the hill to Shasta and the Siskiyuo after a long drive through the valley.

[gmushial]

I was able to poke one of the Z owners last night: a '01 3.0 with 210k miles: original coil packs... so, my interpretation is: ambient temp has less to do with coil demise, than under-the-hood temp, which is probably worse in stop-and-go driving. The other thought is: if the coils go, is more of a crap shoot, kind of like the S54 rod bearings - some owners go the entire life of the engine, never change then and never have problem, conversely, there are those that don't change them in time. But I'd still be interested in other's experience with their coil packs - would be nice to have a statistically significant sample.

[OOZ]

Thanks for the thread. I'm not driving Jinx this weekend because of the weather (rain) so I decided to look into the basic repairs. Surprisingly even after the BMW Dealership Service II that the PO completed at 70k it appears she has original plugs and coils....this was a much easier check than I though it would be. Her M54B30 has only 75k miles and appears to be running very well (reading the mileage threads... I'm on par at 220-250 per tank with city & highway and lead foot) Because she doesn't hesitate to ignite the Orange DSC light on my dash when I'm spirited in her peddles... they are working fine. The reading I've done so far on about all the bmw coil over systems has indicated there is no benefit to changing the coils prior to failure. at $50 each... I'm just replacing the plugs and directing the funds to a COI. interesting enough.... that should about cover it!

[Mpyre]

I have replace 2 of my 6 coils. One at a time on my S52 with 103K miles.

Just replaced a 3rd coil. Had a misfire code on #4. Finally got rid of that idle stumble.