What is the probability of getting the timing chain cover oil leak on the 3.5 liter V6?

I had this on my 2016. I’m in the process of getting a 2023, deposit placed but NO VIN yet. It is downright depressing to think about this issue developing if it’s a fairly common problem. I would like to think if it happened a lot the design of the mating surfaces would be changed to make this leak very unlikely. The warranty repair costs would be huge if it happened within the 5 years, 60,000 mile warranty. So that tells me most happen after 60,000 miles. Mine happened at 59,500 miles but at 70 months. Fortunately I had an extended warranty that covered the cost ($2900).

 

on the 2016-17's higher than the other trucks from what i can tell.

 

Our answer is just as good as yours . Nobody knows. Luck of the draw .

 

Sad to say my 2022 developed the leak with only 2500 miles on it. Needless to say I was not a happy camper even though covered under warranty.

 

Haven't seen it on anything newer than 2018.

Just had a 4runner today that's leaking, 2012 model.

It's not very common. It just gets a bad rap because it's so expensive to fix.

 

Cazman 13, I am sorry for you as well. After seeing the complexity of the repair, you gotta hope an experienced tech works on it. Mine seemed fixed fine. At least no quick failures. The fact that it happened on a 2022 tells me it’s not restricted to older Gen 3s (2016, 2017). I wonder what is happening during engine manufacture? Must be last of attention to detail. It is not a gasket. It is sealant. So it’s obvious if the person or robot is not detailed, it will leak

 

i dont agree, the fact that his leaked so early mileage shows me that its root cause is different than the earlier model timing cover leaks.

 

The dealer I took it to said they see about 5-7 a year on the 3.5. It is not just the Tacoma. The Highlander, Camry and Avalon have the leak to they said.

 

8.521%.

 

Curious on how you discovered this. Just a visual inspection of the area or was there oil on the floor/ground where you park?

 

There was oil on the floor in my garage.

 

I’m sure a bunch of those “leaking” timing case covers are very similar to the BMW oil filter housing leak , they all do it to some extent as they age , most times you clean it up with some brake clean and it’s fine for years , is it leaking ? More like seeping , but the reality is it’s not the end of the world . Sometimes they do require resealing ….

 

Auskip 07, that’s a good point. 2500 miles is like an infant mortality failure. Mine was 70 months but only 59,500 miles. I guess we all need to rely on the 60 month, 60,000 mile warranty. I kept my 1999 Gen 1 Tacoma 17 years. Gave it to my son with 180,000 miles on it when I bought my 2016. He is still driving it. We hunt together. I would like to think I could drive a Gen 3 a long time. I don’t know of any other major widespread issues with the 3.5. I heard of a fair number of crankshaft position sensor failures but I never had it. And I’m sure that repair is not as involved as the timing chain cover. If you buy a GM V8 you have a fair chance of valvetrain issues with the cylinder deactivation. I don’t know of any “bullet proof” engines in mid-sized trucks.

 

Don't freek out pressure wash it and drive it another 100K you might loose a pint.

 

lol!

 

Yes, just luck of the draw unfortunately.

However, I do wonder about a few things related to this issue?
Curious…..
* Why is sealant used instead of a complete gasket?
* Is the sealant that is applied at the factory done by a robot?
* If the repair has too much sealant and makes it way inside the engine it apparently could plug an internal oil passageway leding to oil starvation?

An observation from this forum.
* Repair can be hit or miss and leak can occur again.

No fun. Personally, I would just leave the leak if it wasn’t serious.

 

-Sealant is used because of imperfect castings, toyota has had this issue for many decades, but it's based on tollerances, risk and costs of warranty repairs. Still very low chances. But basically the head, engine, and timing cover don't line up perfectly. So sealant takes the clearances up.

-It's done uniform, it 100% has to be a robot.

-Too much sealant does plug up oil pumps, this happened on the FR-S valve spring campaign, lots of techs killed the subaru engines with sealant.
It also has a second problem, it causes bolts to pull threads, or hydrolock threaded holes. Because of sealant getting in holes, the tech keeps turning with the torque wrench, and it splits out the back.

We have a member on here that had an engine fail months after a re-seal and I'm convinced it's oil starvation due to sealant being improperly cleaned or applied.

 

Thanks for all the details @Bishop84 I could stomach the cost of a repair if there were no possible side effects. But one would really need to weigh the pros and cons on this repair depending on the severity of the leak.

 

Less than the probability you’re worrying about something that isn’t broke and shows no signs of it.