silly spark plug question

[ryota]

Just curious... I was looking at some spark plugs and there are more than I remembered. I read on here that NGK and Denso are the ones I should go with since they are the OEM replacements, but which ones to get? is there really that much of a difference between the copper, platinum, double platinum, and iridium? BTW, I have nothing done to my engine it is completely stock, I just want to keep my engine happy and healthy since the nice weather has let me experience the outside world finally.

[UberSilver]

Against the mass beliefs on this forum, I installed some Bosch ir. They really seem to work well, much better than the NGK's they replaced. I just went for the lowest cost iridiums I could find. I got them at rockauto.com for $22. delivered.

[screenprintr]

NGK's work well too.

[bcat37645]

Not a silly question. Go with Iridium, either NGK or Denso. NGK is IFR5T11, Denso is SK16R11. I just replaced at 100k with Denso...torque to 15 ft lbs, and don't touch the Iridium tip (as in gap is factory set)...it's fragile as heck...good luck. FYI, my 2009 came with NGK from the factory.

[ryota]

My real question was what is the benefit of iridium compared to say platinum? I'm not looking for like tuner grade plugs and wires or anything, like I said just a happy engine. Probably going to stick with OEM, I appreciate the Bosch suggestion though.

[UberSilver]

Originally Posted by ryota

My real question was what is the benefit of iridium compared to say platinum? I'm not looking for like tuner grade plugs and wires or anything, like I said just a happy engine. Probably going to stick with OEM, I appreciate the Bosch suggestion though.

I'm not 100% sure of the benefits of Iridium, other than 100K mile life. There maybe other benefits as well. I went with Iridium because thats what was in the engine. They may also be stock fitment from Toyota.

[ryota]

Thanks, didn't realize that is what was in there before. Appreciate the help.

[esse10]

You didn't specify how many miles on your yaris but if you have 100k and never touched the plugs..LOL You're in for a treat when you try and remove those. Mine were like 40 footpounds from the factory that's why folks should remove them plugs at 50k miles , put anti-seize on the threads and put back in or replace with new. Also clean the PCV valve it's a ten minute job and makes a difference, if you have 100k that is. Good luck man.........mine has 59k and running real good, get's 38mpg and has NGK original iridium plugs.

[ryota]

good to know. I'm at about 75k for miles. i will make sure i try this at work with all of the tools haha.

[YarisSedan]

The different metal types usually corresponding to the ignition system. Older days of distributor ignitions they typically went with copper plugs. Then there was platinum. Then coil over plugs were invented then there was double platinum/laser platinum and then finally iridium. If you put a copper plug in your car it might last as week it would jsut burn through it and cause misfiring. You could probably put a double platinum but it at most owuld last you maybe 50 60k. The best bet is iridium which is designed to last you 100k if not more. Ive changed plugs at 100k and they still look like there is usable life left.

[othater]

My 07 sedan just turned a little over 105,000.
I see a set of NGK's 1FR5T11 on EBay shipped for $30.00 which sounds pretty good.
My concern is having never checking them, what's the chance of them being seized and am I better off taking it to a mechanic with this amount of mileage?
Would it be best to remove the plugs with a cold, warm or hot engine?
Thanks

[mf4361]

Definitely remove spark plugs when its cold. Hot plugs expands and tends to hold onto the cylinder head more tightly.
I changed mine out at about 125000km. It does require some force to break it loose but after that it screws out easily. With a standard size ratchet and extension, if you find it ridiculously stiff, maybe it is better bringing it to a mechanic.