V6 Highlander Spark Plug Replacement - Not Fun!

[CapitalTruck]

Let me tell you something, changing the spark plugs on my mom's 07 Highlander with the V6 was quite the time. Getting that air intake plenum off was a real joy. There are three bolts on the back of the plenum that are awful to get to. Particularly the bolt in the middle. I hope no kids were walking nearby because the swearing was prolific. To get that center (rear) 12MM bolt off I used a six sided 1/4 inch drive socket with a small 1/4 inch "breaker bar" style driver. I would say it took me every bit of 4 hours.

The Highlander has 160k on it. Interestingly enough, the three easily accessible plugs in the front of the engine were NGKs, those in the back were Densos. I'm thinking that at some point my dad must have taken the Highlander in for service and they charged him for a spark plug change and only did the front three. Can anybody else come up with another possible scenario? I have really lost faith in dealers over the years.

Ultimately, this was one of the biggest PIA spark plug changes I've ever done. Like all repairs though, when it's done you're always so happy with the good result and the money saved.

 

[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.

 

[SwampSurvivor]

Some vehicles are pretty crazy now. I used to say I'd stick to inline 4s or overhead valve engines, but even some inline 4s require the intake manifold to come off

 

[NormanBuntz]

If your Dad still has the service receipt for the first spark plug service, I'd take it and the six plugs you removed and plunk them on the service manager's desk, especially if the rear plugs appear more worn. Denso was OEM parts.

 

[Kuato]

Originally Posted By: NormanBuntz
If your Dad still has the service receipt for the first spark plug service, I'd take it and the six plugs you removed and plunk them on the service manager's desk, especially if the rear plugs appear more worn. Denso was OEM parts.


This - IF the plugs are very differently worn.

But

good job, those sideways V6 engines can be a bear to work on.

 

[CapitalTruck]

They looked roughly the same. The front ones were noticeably tighter though.

 

[CT8]

My 1992 v6 Toyota at the first spark plug change has 3ND and the other has 3 NGK !.

 

[slacktide_bitog]

I hope you replaced the valve cover gaskets while you were back there. And of course, you should've used iridium plugs as well, so that you don't have to go back there again

 

[CapitalTruck]

I didn't do valve cover gaskets, just didn't have time. However, I did use iridium plugs! So far no signs of leakage whatsoever from valve cover. I did put a new gasket on the plenum.

 

[CapitalTruck]

That is totally wild. That is how this one was(3 Denso, 3 NGK on different banks). I have no clue why a manufacturer would do that.

 

[simple_gifts]

That sucks.

No sense paying top $$ for the dealer not to do a job, when the corner garage can not do it for a lot less.

A friend of mine had a rendezvous and his mechanic asked him 'never to bring it back' after doing a tune up.

 

[bdcardinal]

The Ford modular V8s that had spark plug wires had different plugs on driver and passenger side banks. They were replaced with the same part number.

 

[slacktide_bitog]

Originally Posted By: CapitalTruck
I didn't do valve cover gaskets, just didn't have time. However, I did use iridium plugs! So far no signs of leakage whatsoever from valve cover. I did put a new gasket on the plenum.


Ahh, too bad, and you were right there too! Because the gaskets will eventually leak, and you'll have to do all that [censored] again removing the intake

It's the same reason you replace the water pump when doing the timing belt

 

[motts]

The factory plugs on my 02 Camry v6 were half Denso and half NKG

 

[Oro_O]

Originally Posted By: motts
The factory plugs on my 02 Camry v6 were half Denso and half NKG


The [censored] they were.

Someone charged a change at one point and didn't do the job. That is the same thing I found on our Camrus (Camry/Lexus).

If you are back there on a 1mz-fe/3mz-fe doing plugs and don't do the pcv valve and at least rear VCG, you are wasting a lot of time.

 

[147_Grain]

Always ask to see the old parts to prevent dishonesty like this.

 

[Kuato]

Originally Posted By: CapitalTruck
That is totally wild. That is how this one was(3 Denso, 3 NGK on different banks). I have no clue why a manufacturer would do that.


If it's from the factory, three things I can think of:

1) They are showing the owner that either is acceptable

2) A test of some sort

or

3) Agreement to use spark plugs from company A in new vehicles. Same agreement with company B...by putting both in, that satisfies both contracts.

 

[Farmer]

CapitalTruck, is this V6 the 2GR-FE 3.5L? or 3MZ-FE 3.3L.

 

[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

 

[Nick1994]

Originally Posted By: simple_gifts
That sucks.

No sense paying top $$ for the dealer not to do a job, when the corner garage can not do it for a lot less.

A friend of mine had a rendezvous and his mechanic asked him 'never to bring it back' after doing a tune up.
Yeah my mom has a Rendezvous. 3 times I've attempted to replace the rear spark plugs, couldn't do it. Removed the coil pack and still couldn't get to them. Couldn't even take off the spark plug wires. I changed the front 3 though.