V6 Highlander Spark Plug Replacement - Not Fun!

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Originally Posted By: Brybo86
Originally Posted By: Leo99
I've heard a lot of Honda come with NGK on one bank and Densos on the other. I'd assume they were the original plugs from the factory.


You're kidding right?
That's the dumbest thing I've heard


+1
 
Two different brands of spark plugs from the factory? I'm not buying it. The story reminds me of these old Golfs.

IMG_1550.jpg
 
This 'business' of just changing the 'easy' plugs and ignoring the 'tough' ones has been often seen 'service' ever since FWD with a V6 became common=over 30 years.
 
Some Mitsubishi's came with standard plugs in the front bank, and plats in the rear under the manifold. So, the question was...if the front plugs have been replaced, did they do the rear?...if the front plugs are worn, shall I check the rear ? [censored] if you do, [censored] if you don't.

I'm not even going to bother unsensoring the censorship. My own diamante got double plats in both banks.
 
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Toyota owns Denso,why would they buy NGKs when they have an endless resource of their own?
 
Maybe Eng20 worked on this car. Bought 6 Denso's from Amazon but was able to buy 3 NGK's for 6 cents/plug cheaper with his Speedperks. Returned 3 Denso's claiming they were defective and got all of money back.
 
I recall reading about Tacoma's having the same thing--one bank is NGK and one is Denso. Dunno why. here's one link where others have noticed it:
https://www.tacomaworld.com/threads/3-denso-and-3-ngk-spark-plugs-any-clues-to-y.123889/

As listed in that link, many companies want second source ability--vendor has an issue, you want to keep your lines going. So you farm business around, never being 100% reliant on any vendor.

*

Seems though that this is a V6 thing. I don't think I've ever read of Toyota using half and half on a V8. I just did plugs on my truck and all 8 were Denso's. Maybe someone did the job before 73k--but since the truck had a been a lease and the job doesn't need to be done until 120k I have my doubts.
 
Originally Posted By: Brybo86
Originally Posted By: Leo99
I've heard a lot of Honda come with NGK on one bank and Densos on the other. I'd assume they were the original plugs from the factory.


You're kidding right?
That's the dumbest thing I've heard


Far from it, I have seen this many times and no its not that someone skimped on the job they were OE.
I bought a brand new Honda bike, the 2 plugs on the ends were Denso and the 2 in the middle were NGK. I would bet money that some sailor didn't open the crate and swap 2 plugs and i bought the bike grey market in the crate so no dealer was involved.
Can anyone explain how they ended up in there if it wasn't at the factory.

The only thing i can think of is the heat range on the plugs is very slightly different.
Running the combo all 4 plugs were an identical color, all 4 of either brand and 2 would be slightly darker.
I did use the combo again and sure enough all 4 were the same, even though they plugs cross match there was a very slight difference but not enough to be any sort of issue.

On that particular bike engine the 2 outside cylinders have more air flow, on a horizontally mounted V engine the front cylinders would also get more air flow
 
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I like that idea Trav, banks run different temp--makes more sense than my idea of second source, given that my longitude engine runs all the same plugs.

That said... do dealerships replace like with like? If it was necessary to run two different ranges of plugs, it'd be in the manual, I'd think.

*

I'm not sure I ever want to own a FWD V motor, those rear plugs are usually a pain from what I've read. I wonder what is worse, plugs deep inside the head (DOHC, plugs deep down in a tube) or on the side, down low, on a rocker valvetrain setup. Probably both just as bad, just for different reasons.
 
Dealerships do not as a rule do like to like, like I said earlier its not a real issue, the spec is very close. I did it only out of curiosity and the parts were both available.
IIRC there was a German (I don't remember the make) L6 that ran different heat range on the 2 rear cylinders but it was at least 30 years ago.
 
Originally Posted By: KrisZ
That's the drawback of having a transverse mounted V6 in the engine bay. I dread the job on my minivan, but at least it's years out.


+1 on that. Some of them are a giant PITA and your arms get nicked from trying to get in there. Chevy Venture vans come to mind.
.
 
My 1996 Zetec 2.0L has a waste spark ignition. It came with 2 different type plugs. Two cylinders had the platinum puck on the ground electrode and the other two had the puck on the center electrode. If you removed the plugs you had to return them to the original cylinders. The replacement plugs were double platinum plugs. I guess Ford was trying to save a few pennies from the factory.

Whimsey
 
Originally Posted By: Farmer
CapitalTruck, is this V6 the 2GR-FE 3.5L? or 3MZ-FE 3.3L.


This is the 3MZ-FE 3.3L

After perusing various Toyota forums it seems as though this is a peculiarity that some of their V6 engines are built with. I guess after 164k miles I'm glad I got them changed out. Just to make myself feel better I called the local Toyota dealership to get a price quote on if they were to do the service. $518.00! That was worth a few hours under the hood, even if a lot of cussing was involved.
 
Sheeesh! I had a 1991 Pontiac Grand Prix with the 3.1 V-6 engine in it way back in the day, and I thought those plugs were a pain!
 
Originally Posted By: KrisZ
That's the drawback of having a transverse mounted V6 in the engine bay. I dread the job on my minivan, but at least it's years out.


The job was easy on my T&C. Different motor than yours, though.

It was seriously a 20 minute job.
 
Originally Posted By: Whimsey
My 1996 Zetec 2.0L has a waste spark ignition. It came with 2 different type plugs. Two cylinders had the platinum puck on the ground electrode and the other two had the puck on the center electrode. If you removed the plugs you had to return them to the original cylinders. The replacement plugs were double platinum plugs. I guess Ford was trying to save a few pennies from the factory.

Whimsey

Exactly.

Most 1MZ-FE engines had a waste spark ignition.
 
Originally Posted By: dishdude
Two different brands of spark plugs from the factory? I'm not buying it. The story reminds me of these old Golfs.

IMG_1550.jpg




It is a fact, that certain Toyota's come with two different brands of plugs from the factory, partly being to keep TWO vendors with good supply of the proper plugs available at all times, each company gets business so they keep producing plenty of product, in the event that either vendor has an issue, they still have a source all the time.

The VW Golf as well as the VW Polo came as a multicolored
model called the Harlequin. The color schemes varied from car to car, all the colors that came on the car could be the base frame and then various colors would be applied to fenders doors, ect...

The Golf below was a floor pan of turquoise, but could be red, navy, yellow, ect.
 
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