Coil pack questions - should they have cracks?

[scot850]

I'll suggest the answer to my question is no. But here is why I am asking. The car was running fine with good pick-up before I took it apart to do the stage 0 work at the start of the year. Today I pulled the coil packs to replace the spark plugs and found all but one (#4) seem to have a brown goop around the top of the boots which is also around the top of the spark plug recesses.

Once I cleaned the crud off the boots I removed then from the coils to clean the remaining brown goo off. Now around 2 and 3 I assumed the brown goo was from the oil leaking from the PCV pipe to the head that had not been clamped properly, but that doesn't explain #1, 4 and 5 which also had it.

What I found on removing the bots is that 4/5 are OE coils, and all of them have cracks in their bodies. This surprised me as the car had been running smoothly (the engine anyway). So the question is, is this a problem which required them being replaced (just used all my spare used ones on the 'R' of course a couple of weeks ago) or is there something I can plug the cracks with and continue using them?

Next question, when replacing the coils into their recesses should you use any grease/paste whatever or should they be dry? I have usually had distributor/spark plugs so don't have much experience of working on coil packs, but my thoughts is they should be dry and clean.

I've attached some pictures of the coils below:

Diagonal crack on side of coil pack

Same again on another coil

Vertical cracks in coil bodies

Same again

The weird thing is the cracks are consistent. One vertical one in the same location and one diagonal one on one side, but always the same side.

Please educate me on things coil pack wise!

Thanks,

Neil.

[JDS60R]

nope - toss them. unless its FCP - then just send them back for your next set.

[scot850]

Thank you wise one! Unfortunately that is what I thought but was hoping against! This car continues to beat me to death. I had just bought a 'spare set' of Volvo coil packs thinking with the issue of the 2000 'R' just blowing one and using all my good spares it made sense to stock up. I got a smoking deal from Swedish Car Parts for $40 US/coil. Now just wish I had bought more. Crap!

I still have 4 IPD HD coils that were working from the 'R' but don't want to mix them with regular Volvo ones in case that may be an issue. Mind you, I don't think the mechanic marked the bad one.

One further point, 4/5 of the spark plugs I am replacing have what looks like burnt insulator ceramic just above the metal body. Is this fairly normal or is it tied to the cracked coils leaking something down to there?

Thanks again,

Neil.

[cn90]

The best way to handle ignition coils is to get good used coils from local junk yard ($10/each) or buy a set of 5 used Volvo OEM coils on ebay for the same money as spare. You can leave these spare coils in the trunk in case you need to replace them.

I bought 5 used Volvo OEM coils ($10/each or $50 total) for my 2005 XC90 2.5T with current mileage of 105K...I have not needed to replace the coil yet.

Back to your coil thingy, the secondary winding is deep inside. On the surface it is primary winding, which carries only 12V.
So, minor cracking as shown in the photos is of no significance. Don't lose sleep over it, especially when you have no error codes.

Another note: the cosmetic cover, remove it and put it in the trunk (and its Torx bolts) simply b/c some people pinch the small wires feeding the coil during installation of the cosmetic cover. Also, without the cosmetic cover, replacing any ignition coil is a snap, even in the middle of nowhere.

[oragex]

Mines too are cracked all over. While not ideal, I don't have an issue with it. If we keep replacing parts just because it may fail one day or just to have everything perfect, it is going to be expensive. Keep a working one for spare and if you get hesitation under strong acceleration replace the faulty coil.

[scot850]

Do coils have oil in them like the old coils on distributor cars? Is that where the brown goop/gunge came from at the top of the coil boots? If they do have (cooling) oil then if they crack and it leaks out it is only a matter of time before they fail.

Whilst I have JDS60R's wise knowledge in mind, I may follow your (cn90 and oragex) suggestions and just stick them back in and see what happens. I don't plan to keep the car for more than a couple of months once it is running, and then look at swapping out one if it fails then.

I can look at the used option too, but I guess you don't know if they are any better until they arrive.

Appreciate all input as usual.

Thanks guys,

Neil.

[abscate]

Run them and don't sweat the small cracks. I've got spares you need one

[BEJinFbk]

Run them and don't sweat the small cracks. I've got spares you need one

+1 !
If it's running smooth and not throwing codes - Drive On.

[scot850]

Thanks guys. I will run them with the cover plate off and see how it goes.

Neil.

[cn90]

Re used coils on ebay.

Most ebay sellers sell decent coils, just look at the photos and ask the ebay seller if you have any questions.
Get a set of 5 used Volvo OEM coils for $59, leave them in the trunk.
Whenever you sell your Volvo (hope not), simply sell the coils to the new owner or resell it on ebay and get your money back.
Basically, you lose almost nothing getting a set of 5 coils ahead of time...