Lexterious

I'm doing the dreaded valve cover gasket replacement. It's a royal pain due to the limited room to do the cylinder bank that is near the firewall.

I'm going to replace all the spark plugs while I'm doing it as I'd rather not want to do much of the same work again.

One internet commenter suggested that I proactively replace the 3 coils on the hard to reach cylinder bank. It sounded like a good idea but spark plug coils are quite expensive.

What's been the group's experience with regard to spark plug coils? Do they fail often? And at what mileage?

MattRX

Many like to do all three rear coils but I left them on my two cars except on my RX where one failed and I did all three. 2002 Highlander w/ 1MZ-FE 300k KM original coils, 08 RX350 original coils at the back at 350km, one was replaced by PO with a cheap one so I just redid them all. I'm used to taking the intake off so I'm not worried if I have to go back in, but the peace of mind on a road trip might make you feel inclined to do all three at the back regardless.

The factory coils last a long time, most if not all 2GRs I have seen in the yard have had all original Denso / DE coils

Oro

I have an 02 ES300 w/333k miles on it. All original coils in the back (one in the front did fail at about 250k miles). That ES runs hotter than the RX back there, also. I have an RX I am about to do the VCGs (184k mi) and I am not going to change the coils, no coil issues with it.

- Land cruiser had two coils fail about 150k, none since up to 220k.
- SLX has 200k and original coils.

Coil failure isn’t predictable, and IME a new one is not a guarantee it won’t happen to it. Different people have different mechanical abilities/repair + risk tolerance/budgets. That’s what works for me but may not be for everyone, of course.

LeX2K

Oil leaks kill ignition coils otherwise they can last the life of the car. If you see a "Denso" coil for less than $100 it's probably counterfeit.

Chapp

Would that include Rock Auto?

Serious question. I usually get all my parts from their and all of their denso parts are significantly cheaper than the box auto parts stores and definitely the dealers.

THey have the denso coils for the rx330 for around $54 a piece, compared to the box auto parts stores for around $80 if they can get it in time for ya.
I just had to replace plus and coils on wife's 2013 highlander, surprise job, no prep, those were $100 a piece, around half that on rock auto. But again I didn't have the time to prep.

Mesquite77

I've had no problem with rockauto denso coils, replaced bank 1 coils 4 years ago, bank 2 coils original still fine, was maybe not needed but it is a PIA to do later...

Chapp

I agree. I did the same on the RX probably 3 or 4 years ago now w/ rock auto denso.

LeX2K

Rock Auto is legit no fake parts from them. A few times they sent me the wrong part but are easy to work with they made it right.

Felix

I've used Rockauto before w/ no issues......High volume keeps the prices down.....Just to add, replaced the rx plugs last yr & running the oem coils still.......

Oro

Another option is this; I’ve done it for years and it has saved me a lot of money.

I look on Ebay and get take-off coils from a wreck, from a reputable yard who states mileage, etc. I but a pack of two or three low-(ish) mile take off coils (say, 60 or 70k). Toss them in the trunk with the spare. Usually only about $10 to $15 per coil for good OE coils.

For you fellow value-hounds out there.

Chapp

Yeah, at this point I almost exclusively use rock auto, unless I'm in an emergency situation like the alternator going out, or for certain parts I want OEM for.
I.e. motormounts.

Just double checking.

Right now I'm torn between getting the dorman control arm bushings and having them pressed out or getting the mevotech premium control arms w/ ball joints.

And yeah, yeah, I know-go to the control arm forum. I am, just making convo.