Spark plug change at 150k

[ddicosmo]

I'm about to hit 150k on my 08 SR5 V6 and I'm still on the original spark plugs. The engine seems to be running fine (not rough and no codes) but I feel as if I'm due for a spark plug change (I think I'm 50k over recommended interval). Which spark plugs do you recommend for the change? Go with OEM or something else? Also, my only concern about the change is that a few bolts on the coils look rusted and may snap upon removal. Does anyone have a link to a good write up on changing the plugs on 4th gen V6? Also, their experience doing this and if any bolts snapped or were hard to remove? Any other gotchas? Any advice would be appreciated before I attempt this... I usually stick to the "if it ain't broke, don't fix it" mantra, so I hope I'm not creating more problems by attempting this...

 

[bombventure]

For spark plugs I’d recommend either Denso or NGK. I’m about to do my plugs this weekend actually. Just picked up some Denso iridium 3421 (SK20HR11) on rockauto for $50, and that’s including shipping.

As for the bolts that hold the coils in place, you can spray some PB blaster on them if you’re worried, just be careful not to douse the area too much, wipe off any excess. Also, if you’re worried they’ll snap off just take your time when loosing them. If you feel resistance when taking them off, go back and forth between loosening and tightening, slowly, and this will likely ensure you get them off. You can also get a 10mm bolt extractor that has rifling on the inside so when you tap it down onto the bolt it will grab onto the head and pull it out easier if the heads are really bad.

As for writeups, just go on YouTube and type in 4th gen 4R spark plug change. There are a few videos that go into depth or good detail about what to remove for access on the drivers side and just good tips in general when replacing them.

 

[Buckaroo]

I'm about to hit 150k on my 08 SR5 V6 and I'm still on the original spark plugs. The engine seems to be running fine (not rough and no codes) but I feel as if I'm due for a spark plug change (I think I'm 50k over recommended interval). Which spark plugs do you recommend for the change? Go with OEM or something else? Also, my only concern about the change is that a few bolts on the coils look rusted and may snap upon removal. Does anyone have a link to a good write up on changing the plugs on 4th gen V6? Also, their experience doing this and if any bolts snapped or were hard to remove? Any other gotchas? Any advice would be appreciated before I attempt this... I usually stick to the "if it ain't broke, don't fix it" mantra, so I hope I'm not creating more problems by attempting this...

I think you ought to do it if you intend to keep the truck - they aren't going to get any easier to remove. I have never had trouble removing those bolts that hold down the coils but you might use a little bit of PB Blaster on them, let them sit and give them a try. If they don't move, alternately loosen and tighten them until they break free. If you have trouble getting the plugs out, I would do it with the engine at operating temp. Again, alternately loosen and tighten if they don't move.

Your owners manual specifies either of two spark plugs. I would go with one of these. Buy from a reputable source (not E-bay or some third party seller on Amazon) as there are many counterfeits out there.

4.0 L V6 (1GR−FE) engine
DENSO K20HR−U11
NGK LFR6C11

Rockauto is a good source but I recently bought OEM plugs from Ourisman online parts which were cheaper than Rockauto....go figure. While your doing it, you may want to replace the coil boots as well.

 

[ddicosmo]

Thanks for the responses. I called two Toyota dealers and both quoted $5.35 each for replacement OEM (Denso) plugs... $50 seems high for the Denso plugs... are they different from OEM? I thought the OEM ones from the dealer are also iridium...

 

[bombventure]

Those spark plugs are nickel, so they are cheaper. The Denso ones I purchased are iridium. They last a lot longer. Really its just preference on your end. Either will be fine.

 

[Buckaroo]

Thanks for the responses. I called two Toyota dealers and both quoted $5.35 each for replacement OEM (Denso) plugs... $50 seems high for the Denso plugs... are they different from OEM? I thought the OEM ones from the dealer are also iridium...

I run the recommended plugs. For the 2008 4Runner, the recommended Denso plug is Nickel U-Groove. Because they are Nickel, the recommended replacement interval is 30,000 miles so you are 120,000 miles overdue. Take a look at this video from The Car Care Nut starting at 11:15....note comments at 12:30....
https://www.youtube.com/watch?v=G5xFLj5baJw

From Toyota, online dealership price of $4.15 each plus shipping.
Genuine Toyota Spark Plug part# 90919-01235 for 2003-2015 Toyota | Ourisman Toyota Parts| Official Toyota Online Store

Same plug from Rockauto - $4.38 each plus shipping
More Information for DENSO 3381

Alternate NGK recommended plug is also Nickel, from Rockauto - $5.54 each plus shipping.
More Information for NGK 7787

 

[ddicosmo]

Thanks Buckaroo for the info. Interesting video about the plugs for the 4runner. Sounds like my 2008 came with the 30k plugs. I was mistaken (like alot of people) thinking that they were iridium. I even asked the parts guy at the Toyota dealer if the plugs I was purchasing were iridium and he said yes. But the ones he gave me are the K20HR-U11's which are exactly the same as what came with my vehicle. They are not iridium but copper like you said. Well, I guess I'll be doing plugs again at 180k then. I have all but one of the original plugs removed as one of the flange bolts is rounded and I need to get an extractor socket to remove it... There was a big difference in the gap from the old to the new. The gap on the old plugs was over .06 (should be .04 or 1.1 mm). So they were definitely worn out and on most of the old ones, the center electrode was worn at an angle.

One thing I noted which seemed odd and concerning, was that on the left side bank of cylinders (facing vehicle from the front), I could see what looked like some rust inside the cylinder when I shone a borelight down there... It seemed that the rust was on the sides of the cylinder (the tops were black from carbon fouling). The right side cylinders did not appear to have any rust at all... It seems that the left side cylinders and coils are more exposed to the elements because all the flange bolts on the left side bank were all heavily rusted (the tops) whereas on the right side, the bolts had very minor rust and were in much better condition. The right side bank is covered with more parts though so maybe that is why they appeared to be cleaner... In either case, what seemed like some rust in the cylinder on the left side has me worried... Has anyone else seen this on their vehicle? I've taken great care of the vehicle and always change my oil at 5k with synthetic, so not sure why there would be what appears to be rust in the cylinders... Should I be concerned about this? The vehicle runs fine but that kind of shocked me.. I wasn't expecting to see that...

 

[AuSeeker]

Thanks Buckaroo for the info. Interesting video about the plugs for the 4runner. Sounds like my 2008 came with the 30k plugs. I was mistaken (like alot of people) thinking that they were iridium. I even asked the parts guy at the Toyota dealer if the plugs I was purchasing were iridium and he said yes. But the ones he gave me are the K20HR-U11's which are exactly the same as what came with my vehicle. They are not iridium but copper like you said. Well, I guess I'll be doing plugs again at 180k then. I have all but one of the original plugs removed as one of the flange bolts is rounded and I need to get an extractor socket to remove it... There was a big difference in the gap from the old to the new. The gap on the old plugs was over .06 (should be .04 or 1.1 mm). So they were definitely worn out and on most of the old ones, the center electrode was worn at an angle.

One thing I noted which seemed odd and concerning, was that on the left side bank of cylinders (facing vehicle from the front), I could see what looked like some rust inside the cylinder when I shone a borelight down there... It seemed that the rust was on the sides of the cylinder (the tops were black from carbon fouling). The right side cylinders did not appear to have any rust at all... It seems that the left side cylinders and coils are more exposed to the elements because all the flange bolts on the left side bank were all heavily rusted (the tops) whereas on the right side, the bolts had very minor rust and were in much better condition. The right side bank is covered with more parts though so maybe that is why they appeared to be cleaner... In either case, what seemed like some rust in the cylinder on the left side has me worried... Has anyone else seen this on their vehicle? I've taken great care of the vehicle and always change my oil at 5k with synthetic, so not sure why there would be what appears to be rust in the cylinders... Should I be concerned about this? The vehicle runs fine but that kind of shocked me.. I wasn't expecting to see that...

I highly doubt that you're seeing rust, most likely it just a film of oil that looks like rust, the piston rings wouldn't allow rust to form on the cylinder walls, I have never seen rust form inside a cylinder unless it has sat for a long time without running.