I was really talking about transverse V6 applications, such as Camry, Accord, etc.
On many cars, the intake manifold is split into upper and lower. The lower bolts directly to the heads. It is often aluminum. The upper is often made of plastic, and that’s the one that is removed to get to the plugs, injectors, etc.
What you were talking about on your own car is the intake manifold. You don’t have reason to remove it for routine maintenance
In some regards, in some instances, transverse 4 cylinders are easier to work on than transverse V6
My concerns mirror those expressed here, difficult removable or breakage at that mileage and also efficiency of “old” plugs. I think I’ll go with 60k and cut the recommended mileage in half. Thanks everyone! Rocketman
rocketman, it is your car and your choice, but if you review all the posts in this thread, there is a trend. All those who have indicated actual hands on experience with Toyota’s using this Iridium plug have told you that there is no need to remove them early and they don’t seize. Several have said that they regretted removing them early.
The only people recommending that you do remove them early have not indicated that they have experience on Toyota’s using Iridium plugs and many have referenced other vehicles. So it is your choice.
Just pulled the original plugs out of a 2007 Yaris Sedan. Has 170,860 Miles on the Original NGK Iridium plugs. They look just fine. I put them back in.
I just changed the plugs in my Civic at 100k, iridium tips so Honda recommends every 105k. Plugs themselves weren’t too bad but they were partially seized in the aluminum head so I had a devil of a time getting them out. Big glob of anti-seize on each before the new ones went in so the next owner won’t have the same problems. Car runs a lot better so probably worth doing early if only to avoid having them corrosion welded to the head.
@Johnathan_Waters, thanks for resurrecting an old thread.
Plugs are pretty cheap, if I am getting them out then I change them.
As @Viffer 's experience, I do not follow the OM on this and change the plugs earlier. Usually easy to do unless like this thread in the beginning, you have a transverse mounted V6. Still one or two years earlier doesn’t end up costing that much extra.
Change them out at around 50k so it comes out smoother. I changed mine at 90k and it has slight seizing problems, although it was still able to come out.
Its best to do all major maintenance at around 60k miles so that nothing rusts up and you can catch any problems.
Here is a general question. If I am changing spark plugs, should I do it when the engine is cold or when it is hot? When it is hot the plug is bigger and the hole is bigger.
Ray and Tom discussed this question on recent podcast. IIRC they said on most cars, cold, but some car manufacturers recommend doing it on a warm engine.
Here’s a puzzle, not sure if it was on the radio show, but I think it has been discussed here at some point. Say you had a very thick flat steel plate with a 2 inch diameter hole it in at room temperature. If you heated the plate to a higher temperature, say 150 degree F, would the hole be larger, or smaller?
Another way to think of it - if you have a solid piece of steel and scribe a 2" circle on it, will the circle get bigger or smaller when you heat up the piece of steel?
I can tell you this, metal expands when heated as a rule of thumb… That is why they heat up the Barrel part of the wheel and then drop the Drop Center down into the Barrel to join the 2 parts…
Plus you can heat up a press fit pinion bearing (and others) and freeze the pinion shaft to install the bearing without a press…
Or freeze a ball joint before installing it to make it easier to press it in…
Also when I was opening up the ID of the inner pinion bearing for a slip fit while I was finding the correct shim thickness, I was using a carbide bit and I could get a good slip fit and then after a few seconds the bearing would cool back down from cutting it, and it would stick to the pinion, took me a minute to remember that while cutting the bearing it was heating up just enough it would slip down in place on the pinion then I would have to knock it back off… lol… It didn’t take very much heat to open the ID (after a lot of grinding) of the big inner pinion bearing 0.001 and hang on the pinion when trying to remove it again…
So even though I have never tested it, I am going to say the hole in a flat piece of metal it will expand when heated…
My heat-related car-repair diy’er story: I was rebuilding my truck’s carburetor, and for the life of me I couldn’t unscrew the two jets. They seemed like they were welded in place. I took the carb to a strong-looking mechanic, and even he wasn’t strong enough. I put my thinking cap on, decided to try cooling the jets with ice to shrink them a little. That, combined with a big hefty screwdriver, did the trick.