Do I really need to get new o-rings when replacing fuel injectors?

[JoshKY]

I am replacing a fuel injector that seems to be cutting out when the engine heats up and it causes a misfire. I went ahead and pulled all six from a 3rd gen 4Runner at the pick and pull and I'm going to clean 11 (not the one from cylinder 4 that I know is causing the problem), check the voltage reading on each, and go with the six that spray the best and have the least resistance.

Now I've been told ts important to put new o-rings on when I do this. Well there are o-rings on both the end that connects to the fuel rail and the end that sprays as well as a larger rubber gasket that seals around the center of the injector toward that spray end.

The local dealership said for one of those type of o-rings its like $6 a pop! I almost bought a $2 kit of assorted o-ring sizes at Bargain Supply today, but I wasn't sure if that might be even worse than leaving what's already stock on the injectors currently?

I understand replacing things like a PCV valve and a dry-rotted grommet, but honestly these o-rings look fine. Do I really need to spend the money on a set of new ones and if so, which ones?

 

[Harleydoc]

I don't if they are good some silicone lube and back in the hole they go


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[02_SE_Runner_DAD]

Install some new ones, they dont cost that much.

 

[Rock_Rat]

^^^^exactly

 

[Jayjayb96]

Agree with everyone. Buy new orings! I had to replace my knock sensors and wiring harness so i had to pull the fuel rail and injectors and manifold. After putting everything back i had fuel squirting out of the injectors. Turned out that the orings on the top of the injectors were crushed on three of them. Took everything apart and bought new orings and lightly lubed them with vasoline and voila! No more fuel leaking. Bottom line...save yourself some time and do it right the first time to avoid any headaches!

 

[runnyrunnerton]

Yes. Yes you do.

 

[JoshKY]

Okay so the consensus looks like replace the o rings. Now which o rings? On both ends of the injector? The large gasket in the center as well?

 

[AntleredRuin]

Replace the ones on either end. You can get the rings from any parts house also. I had to remove all my injectors to remove the fuel rail to safely replace the FPR a couple years ago. Most of the rings were all cracked. Got some replacement rings for either side (12 total) for just a few bucks (NOT $6 each) and still no leaks. Also, bought an Autozone injector because I broke one and it still works great.

Also, not sure if it made a difference, but it can't hurt; I stored the injectors in a jar of gasoline while they were removed. Not sure if 'drying out' is an issue, but it at least kept the dust out of them.

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[Buckaroo]

Do I really need to spend the money on a set of new ones and if so, which ones?

Definitely do not recommend using generic o-rings - the size and the composition will likely not be correct - better off using the old ones.

You need to replace them, however, because the o-rings deform over time so you risk leaks because they don't seal (think leaking gas and fire....of course in the automobile industry, the term fire is not good for business...they call them thermal events). You should replace both the o-rings on the injectors and the crush washers on the fuel rails even if you just remove and reinstall them. These are the parts I purchased for my 3.4L....

Purchased from NAPA
Kit for One Injector - Upper and Lower O-Ring
PART #CRB 212077
Currently $2.70 /Kit at my store

Purchased from Dealership
Fuel Rail Crush Washers - need two per side
Part#90430-12026
Paid $1.70 each

Buckaroo

 

[JoshKY]

Definitely do not recommend using generic o-rings - the size and the composition will likely not be correct - better off using the old ones.

You need to replace them, however, because the o-rings deform over time so you risk leaks because they don't seal (think leaking gas and fire....of course in the automobile industry, the term fire is not good for business...they call them thermal events). You should replace both the o-rings on the injectors and the crush washers on the fuel rails even if you just remove and reinstall them. These are the parts I purchased for my 3.4L....

Purchased from NAPA
Kit for One Injector - Upper and Lower O-Ring
PART #CRB 212077
Currently $2.70 /Kit at my store

Purchased from Dealership
Fuel Rail Crush Washers - need two per side
Part#90430-12026
Paid $1.70 each

Buckaroo

So whatever that CRB 212077 kit goes to, it is not the factory injectors. I looked at those in NAPA and there was one of the smaller o rings that goes on one end, but the only other ring in the kit was this larger gasket that didn't match anything on the injectors my 4Runner and the one I pulled the spare injectors from. The description said they were for a something-something type of injector... I can't remember what the guy said.

#ES 70600 is what I needed. Four of those small o rings come in a box. I noticed the old o rings, although still dark black and flexible, were flattened and fit more snug in than the new ones. I figure when the injectors get plugged back in place the new o rings smush down and create a tight seal. Thanks for the recommendation!

 

[Aidio95]

Replace

I've read that fuel leaks at the injectors are quite common on the 3rd gens and I would definitely say it's worth it to replace them.