Ignition Coils... Wear item? When to replace?

[JeffKeryk]

We see more and more posts about replacing ignition coils.
I recently replaced a bad coil on a friend's 2009 Corolla; thanks to the great feedback from this forum I saved some bucks on the brand.

I have 2 vehicles approaching 200K miles; wifey's beloved 2006 TSX and my trusty 2001 V8 Tundra.
Does it make sense to R&R the original coils?
Remember gas is pretty expensive in sunny Silicon Valley...

I appreciate your thoughts.

 

[KGMtech]

If you have been good about changing the spark plugs on schedule, then the coils should last a while. Big spark plug gaps from worn electrodes force the coils to work hard to bridge the gap, this can cause the coil to fail sooner.

I'd purchase 2 new coils to keep on hand, if you develop misfire down the road, you can make the repair without needing to find the parts store with the right quality at the right price.

 

[Y_K]

It makes sense to replace coil rubber boots with every spark plug change. Just twist and squeeze them gently to inspect for cracks and tears

 

[dishdude]

When they fail, this is something that can last 50k or 500k.

 

[dishdude]

When they fail, this is something that can last 50k or 500k. As far as gas savings, there won't be any.

 

[andyd]

YK a dab of boot grease on the plug at install is a good thing

 

[maxdustington]

Originally Posted by KGMtech
If you have been good about changing the spark plugs on schedule, then the coils should last a while. Big spark plug gaps from worn electrodes force the coils to work hard to bridge the gap, this can cause the coil to fail sooner.

I'd purchase 2 new coils to keep on hand, if you develop misfire down the road, you can make the repair without needing to find the parts store with the right quality at the right price.
+1 nice post. You might get better MPG but it won't offset the cost of the coils, especially if you pay for quality coils.

 

[atikovi]

Kinda like the question posted once before asking if they should replace their 200,000 mile radiator, headlights or struts. You can, but why waste money on it if you don't need to. Bad coils are readily apparent from misfire codes and basic diagnosis when they do go bad.

 

[dishdude]

Originally Posted by atikovi
Kinda like the question posted once before asking if they should replace their 200,000 mile radiator, headlights or struts. You can, but why waste money on it if you don't need to. Bad coils are readily apparent from misfire codes and basic diagnosis when they do go bad.


Exactly. You can make this case for countless parts on the car, the only solution is to replace all of them...with a new car!

 

[Warstud]

Originally Posted by dishdude
Originally Posted by atikovi
Kinda like the question posted once before asking if they should replace their 200,000 mile radiator, headlights or struts. You can, but why waste money on it if you don't need to. Bad coils are readily apparent from misfire codes and basic diagnosis when they do go bad.


Exactly. You can make this case for countless parts on the car, the only solution is to replace all of them...with a new car!

Good Point.

 

[mclasser]

Sometimes, coils fail slowly. I had a coil fail on my sig. Elantra at only 11k miles. Since new, I would intermittently get a lumpy idle. Sometimes, turning on the A/C would bump up the idle enough to fix it, others time, not. A month before setting a CEL, I felt random jerks when the tranny shifted and got extended cranking on a few morning cold starts. Everything's been silky smooth ever since the dealer replaced the bad coil.

IMO, if good quality coils are cheap enough for your high mileage cars, might as well swap them out. You might notice a smoother idle or better MPG afterward.

 

[demarpaint]

I'm thinking when I change the plugs on my 3.6 Pentastar I'll change the coil packs. The intake manifold has to come off to access them on the left bank of the engine. It's a job I'd rather not do twice.

 

[92saturnsl2]

I would not replace any of my OEM coils unless a failure is evident. New coils can go bad too!

These just aren't a wear item plain and simple. Brake rotors, pads, things like that physically wear out. There is nothing inside a coil that has a predefined lifespan. To preemptively replace them, IMO, is throwing money in the toilet. I keep most all of my vehicles to 200k or more and I've only replaced one coil in my 20 years of driving. The CEL code told me exactly which coil to replace, I replaced it with a used part and it's been fine since. This isn't something that will leave you stranded, so while you shouldn't drive with a failed coil, you can get at least get home or to a mechanic for repair.

 

[slacktide_bitog]

Coils are not a wear item to be replaced at regular intervals

And also, it's easy to replace the coils on that Corolla, so even if the other ones eventually go bad, they are easy to replace one at a time.

 

[Y_K]

Originally Posted by slacktide_bitog
Coils are not a wear item to be replaced at regular intervals

On some German vehicles I owned they were, but it may have changed now.

 

[slo town]

OP:

My recent experience with ignition coils.

FWIW,

Scott

https://www.bobistheoilguy.com/foru...adside-assistance-experience#Post4960290

 

[BMWTurboDzl]

The only hassle about coils is that the boots can sometimes tear when you pull them off to change plugs. IIRC it's generally accepted that you shouldn't mix-match manufacturers. I know with my vehicle coils are expected to be replaced every 100k miles.

 

[Mr Nice]

On our Hondas and Acura never.

 

[JeffKeryk]

I was not planning on replacing the coils, but I have to wonder what 200K miles does to them.
On the Tundra, a loss of 1 cylinder is only 12.5% of the total, while on the TSX it is 25%.
If I were a better technician, I might even know how to measure and test them.

The other problem is decent coils will cost $250 or even triple that for the 8 cylinders.
Cheaper ones are a crap shoot at best; I hate cheap parts.
I do think ignition coils are a wear item, as they do fail in time.
On the other hand the original coil in my '68 L36 Vette is still going strong...

Thanks to all who posted.

 

[BMWTurboDzl]

Originally Posted by BMWTurboDzl
The only hassle about coils is that the boots can sometimes tear when you pull them off to change plugs. IIRC it's generally accepted that you shouldn't mix-match manufacturers. I know with my vehicle coils are expected to be replaced every 100k miles.



Oh and not all boots require dielectric grease. Sometimes it can prevent the coil from seating properly consequently some boots are powder coated.