I am replacing my spark plugs and wondered if it's smart to change out the ignition coils at the same time? I have 111,000 miles on the engine running with the original ignition coils. Thanks
Reading between the lines: you're thinking getting to the plugs is so much work, you don't want to repeat it? I wouldn't sweat it, second time it goes faster. Agree with @bisco too, it's not like a water pump, a critical item where failure could damage the engine (I think...). I would just replace them if/when they fail.
You hit the nail on the head! First time changing the plugs! I have watched the Nuts and Bolts guys video and think I can handle it. Thanks for the advice. Prius Chat is a must for us do it yourselfers!
Regarding the video, the Repair Manual spec for spark plug torque is 15 ft/lb, presumably with dry threads *. If you use anti-seize, I would say very sparingly, maybe apply it then wipe it off with a rag: that'll leave a slight amount in the grooves. Then reduce torque to 12~13 ft/lb. Or hey: 15 ft/lb and dry threads. * In the video they really lay the anti-seize on thick, and he mentions 20 ft/lb. I'm reluctant to disagree, one of them at least was a dealership mechanic IIRC, but yeah maybe in this case. Attached are a couple of excerpts regarding the spark plugs. It is goofy: the main section on spark plugs makes no mention of spark plug torque. That is way across the document in another section. Both sections attached.
Note the torque on the coil bolts is considerably less. I don't have the spec in front of me but the first time I changed my plugs on my Gen II I did manage to snap one of those coil bolts as I wasn't expecting how low it really was. Luckily, once the tension was off, I was able to extract the broken bit by hand.
The coil bolt is just a locator/hold-down bolt. The big issue I think, is the repair manual lists an inch/pound torque spec for that bolt, which is twelvefold less than a foot pound. Novices have dutifully set a 1/2" drive torque wrench to the value, but in foot/pounds, and naturally snapped the head off. Yeah just use common sense, lol. I wouldn't use a torque wrench, just tighten it with a ratchet wrench, one-handed on the wrench fulcrum: that'll keep you out of trouble.
WOW ... Just for fun I looked up the coils on mine; 2005 Gen2. ... Those bad boys are $22 a pop + shipping. ... I wouldn't replace them unless you jacked one up in the process of changing the plugs.
That's not bad. Up here if you just walk into the dealership parts department, and ask them flat-footed for just the spark plugs, it's not uncommon to hear numbers like $24 apiece. Canadian dollars, but... I go to a small automotive specialty shop; they're very competent, have or can get most anything. There the plugs are a mere $16~17. Owner's Manual, page 562, says: DENSO SC20HR11. I believe though, sometime since publication, Toyota revised that to SC16HR11, which is slightly hotter. Verify with dealership parts department, but you can buy that plug anywhere. Automotive specialty stores typically are cheaper. There's been talk of counterfeit plugs, especially online purchase, EBay. I'd be cautious. I think your best bet would be an automotive specialty store with a good reputation, been around for a while.
Plugs ... If it's me ... I'm going w/ the NGK 4912 Laser Iridium ... about $7.50 / pop. I go w/ a little touch of anti-seize and twist nice and snug hand-tite.
Update ...I just changed out my plugs and found it a fairly simple procedure.But, I found two things that are different when changing these plugs compared to my 350cc V8. The plugs don't stay on the 9/16th socket and my old spark plug socket was to thick for the throat of the plug wall! I used a very long pair of hemostats to grab the plug and remove it and bought myself a new deep 9/16 socket! Just thought any other newbies out there might want to know.
Does the 9/16" socket have the rubber insert? That'll grip the plug securel. Sometimes too well, to where the socket will pull off the extension after installing the new plug, stay on the plug. To avoid that wrap a few winds of tape over the junction.
Snapon uses magnets in there spark plug sockets. Much better than the rubber. I used those before, a pain! You can also use some hose, fuel or whichever, to put over the top of the plug, then start it so you know it's not cross threaded, them pull the hose off. You only need to push it on enough to hold it.
I'm ok with the rubber insert; they're commonly available here. Except that when the sockets are brand new they can be too tenacious. Test them: put the socket on an extension, then push in the spark plug, then pull it off, and see what separates from what. If the socket pulls off the extension: wrap the joint with some tape.
If you want to go the cheap way, you could spray them with oil or something so it will hold it long enough to get the plug started but then slip off easily.
