I'm back. Been away for a while. I tackled the spark plug change I said I would do. Pretty easy. Remove the relay box, unbolt the spark plug wires, and remove the boots and plugs. My NGK iridium plugs were worn out. The center electrode was almost completely gone. I installed 4 new Autolite copper core plugs. My 07 has 170k and I believe the NGK's were original from the factory. One plug came out extremely hard and I was worried about thread damage, but all is well. The new plugs were installed with anti-seize compound. Now, I will see how long these cheap plugs will last. I've always used Autolite copper in every car I've owned and never had a failure. Well, my slightly rough idle is gone. Now, I need to change my daughter's 09 plugs.
Don't change your daughter's car until you've driven on yours for a few months. I'm not sure you'll be that happy with the cheap plugs. The car runs best on NGK and Denso plugs
The plugs are oem rated. The only difference is the expected lifespan of the plug. Platinum is more durable than copper. Iridium is more durable than platinum. I prefer to change my plugs more frequently to avoid thread damage to aluminum heads.
I’ve found copper auto-lite plugs will be worn out by the time you get too the 60k mileage rating, if not sooner. Of all the different vehicles I’ve had in the last 25 years, I drive about 36k miles annually. The vehicles with conventional auto-lite plugs worn out the fastest. iPhone X ?
NGK plugs are wonderful for aluminum heads. The NGK tri-valent metal plating is the bees knees for anti-seize, if you please. No chemical treatment needed. Copper plugs are great for their low cost, but they never last as long as the exotics.
Anti-seize on spark plug threads "complicates" torque value too, I think. Toyota's Repair Manual is a bit boneheaded on spark plug specs: lists most of the info in one location, AND the torque value way across the book, together with the valve cover info:
Wow, I love priuschat. Full of useful info and always civil discussion. I wasn't aware of the anti seize ability built into NGK plugs. But , one NGK came out with difficulty and scared me. NGK plugs are $9 and the copper Autolites are $2. This is only a test. We will see together how far I can go.
I can't claim any positive experience with Autolite ignition parts- but on the other hand I've never attempted to maintain a Chrysler product where they are predominantly used. They would be my first choice in any Chrysler engine. I try to use plugs that are "in the family" for each machine. I would never dream of using anything but NGK in my Subaru, Toyota & Hyundai. Likewise it's nothing but Champion in my Briggs & Stratton, and strictly Bosch for VW.
I felt about the same way you did, until recently. NGK is a great plug, and that's all I used in Asian cars since I began driving them. But I did my research, and Denso is every bit as good, and they're what Toyota installed at the factory, so that's what I installed this time.
I've heard of problems recently- but on the other hand the last Champion I put in my generator got me through the past 8 years. A lot has changed in that time. I'll keep it in mind going forward though. Honestly the only part of your plan that elevates my eyebrows is the thought that the use of copper plugs is somehow better than exotic. From my point of view, every time you change the plugs is an opportunity to screw something up. Therefore the fewer changes, the better. Exotic electrodes enable very, very long runs between changes. My Subaru suffers obnoxiously poor access to the plugs. It's an incredible pain in the butt to change them. I'm sure there are other difficult cars but the only time I've had it worse was a Porsche 914GT, which required engine removal to change plugs. In those restricted-access cases, I want the longest running plug I can buy, even if it's $15/jug. I haven't had the Prius long enough to change plugs, but it looks about the same as our Hyundai Accent- a trivial affair to get at them.
I favor Denso electric & ignition parts for Asian applications, generally speaking. I feel like their plug application list was... incomplete until recently.
For clarification. The only quality difference is durability. Iridium is far better than copper. As a former mechanic, I choose to change plugs and oil sooner than oem recommendations. I will change my plugs at 50000 mile increments, so the added expense is a waste of money. Plus, I'm overly paranoid about head damage from past experience as a mechanic. There is nothing more irritating than pulling a head because a broken, stuck, or stripped plug.
Our previous Civic Hybrid had 2 plugs per cylinder; I believe they fired slightly offset to improve combustion. Anyway, when I pulled the factory plugs, the front row was NGK, and the back row Denso. Or vice versa, anyway: one of each. The Owner's Manual spec'd both as being acceptable.
