E350 ignition coils

[jillhop]

I have a fairly new-to-me 1998 Coachman motorhome on a 1997 E350 chassis. At the time I purchased it this past July, it was not running well (check engine light on) and had two bad coils, which were replaced (then ran great!). My mechanic commented (sort of joking, but also sort of not) that I should keep a spare in the vehicle, as more were likely to go. Well, last week it started running rough, poor power on the freeway, and the check engine light is on--another bad coil!

My question is, should I just bite the bullet and have them ALL replaced at this point? Seems like it might be cheaper/more dependable in the long run--no pesky labor charges to figure out which coil has gone bad! My main concern is to have a reliable vehicle. While I'm not doing any trips over the winter, I am planning a long (10 days, 800 miles in each direction) trip in the early spring.

[jillhop]

It is a V-10. I have read a bunch of posts on this forum warning about the dangers of changing the plugs on this engine. My mechanic also knew that the plugs were an issue, although he said that he does have the special tool required to remove them if they break. I'll have to do some searching here to find the posts I read about the spark plugs ...

[rooney77]

What engine is it? I've not ever heard a legit mechanic recommend to not change plugs. They are a wear item, just like tires. Basically what he told you would be akin to "Don't change your tires cause rims rust and tires can be hard to change".

I'd find a new mechanic or learn to change coils and plugs yourself. If you do go the DIY route, do not get your coils from Autozone. Every electrical component I get from there is the lowest quality. Also, invest in PB Blaster. Spray the plug bases a few times the day before you plan to change them (don't drive it after spraying them) and a couple times the morning of. They should back out fine.

edit: If time isn't an issue, Rockauto is where I get the majority of my car parts. If it's an "I need it now" situation I try to find an O'reillys.

[enblethen]

I would be having Ford replace all the plugs. I think I saw where there is a tech bulletin about plug replacement.
I would then go with after market coil assemblies. When installed they need to insure boot grease is applied.
This is a V-10?

[jillhop]

It is interesting that the latest coil to fail is in the same position as one of the failed coils from the summer (#3). At that time, they switched the #3 and #4 to verify that they had the right one, then changed #4 and #8 (which was also bad, I guess--I didn't quite own it then). For now, my mechanic is going to just replace the #3 and have me drive it locally for a while, to see if that one fails again. If so, he'll investigate the spark plug ...

[jillhop]

My understanding is that it is best NOT to change the spark plugs in this particular engine until really necessary, as they are very prone to breaking off/stripping the threads. The motor has 61,000 miles, and the owner's manual calls for changing the plugs for the first time at 100,000 miles. The coils that are there (besides the two that were replaced over the summer) appear to be the originals.

My mechanic is saying that the coils cost ~$60 each (plus labor to install).

[Sfla2]

1 thing to do i was told by ford when u do coils also do plug as bad 1 can hurt coil. Had 1 done in GA just coil lasted abt 6k lost same 1, went to diff F deal in Daytona he said always do plug, F stood behind warrenty paid for the 1 in Daytona

[rtz549]

I've read before that as the spark plugs wear down and the gap gets bigger; it puts more load on the coils and that's what kills them.

How old are your plugs? What's the gap set too?

If you get new plugs; set the gap at the smallest spec so as they wear; they last longer then setting the gap closer to being out of spec.

Check on here for various brands and check prices on the coils that are out there: https://www.rockauto.com/

Also check Amazon and ebay for coil prices.

I'd personally put new plugs in and a fresh set of coils and keep the old coils as spares.