quote:

Originally posted by David Lee:
Seems like I read, back when this happened, it was a mere 2,000 blocks found to have debris in them, all machined at Huntsville, Al. That said, why they recalled 102,000 vehicles is likely to CYA with the Customers. I know a bit about casting and machining cast aluminum vs cast iron. The cylinder sleeves in this V6 are cast iron. I can see debris causing oil flow restriction and, especially if it is aluminum chips or particals. Enough junk built up and the steel parts begin heat seezing and wear. I would be interested in your further thoughts Black92 why you think its anything other than machining debris. Ive seen Ford engine blocks, here in Florence being dunked in a chemical vat to be cleaned and, Ive fed robots Ford heads in pairs to be machined. Its a stupid job. The bot unloads the 3rd mill, places a pair of heads to be hand deburred by a human, advances the pair from the 2nd mill, to the 3rd, the pair from the 1st mill into the 2nd then, loads the pair I place into the 1st mill. Again, one feels about worthless feeding a robot.

Your theory sounds like it would be the common sense opinion and it’s one that many manufacturers like to use because no one wants to admit to a design flaw. That sounds infinitely worse than some dirt got in there.

The video I posted above answers your question. Basically it is debris causing the problem but it seems to be a possible tolerance issue that causes a problem and then throws debris all throughout the engine.

The reason the guy I posted believed that is because none of the rod bearings had a problem. It’s the end bearings and all of them are oiled by the exact same system as the rod bearings.

This message has been edited. Last edited by: 1s1k,

They should have continued to develop and improve the 5.7 rather than build a turbo charged turd that will never live up to its predecessor in reliability, longevity and simplicity.

quote:

Originally posted by stickman428:
They should have continued to develop and improve the 5.7 rather than build a turbo charged turd that will never live up to its predecessor in reliability, longevity and simplicity.

This. Toyota has built some very successful, very notable V6 engines (as well as some very successful, long lived inline motors), but a large base like the Tundra is better served by an easy going V8 with effortless low rpm torque and higher displacement based ponies. Toyotas V8 engines have all been excellent, reliable, and VERY long lived with proper maintenance and upkeep.

My 03 Tundra just had its catastrophic perforating frame rust repaired by an off road shop in Winchester Va for just under 2 grand. I posted a thread a couple of years ago about the rust issue and it’s been a long time coming to correct it. It has 88k actual miles on the clock and the VERY localized frame rust was the only flaw needing attention. I just wish the 4.7 was not a timing belt interference motor. I’m due on time (over 10 years) although the belt itself only has about 35k on it. I suspect it could go thousands of miles without issue, but it’s not worth taking even a small chance I won’t destroy it by pressing my luck. In a month or so, that will run me another grand or so but afterwards will be bombproof for the next 10 year or 100k scheduled interval.

I watch this channel on YouTube and this guy finally got a hold of one of these engines from a customer and does a complete tear down showing all the debris in the engine and where it comes from.

If you’re into this stuff it’s very interesting..

https://youtu.be/6QKr9qIgIEM?is=CYmy9GyBqzR1lh4h

Here are a couple of guys I watch frequently on YouTube. The first is a dedicated Toyota guy that is extremely knowledgeable on pretty much every Toyota model and power train in modern times. The second is more of a general engine tear down and autopsy guy for just about any manufacturer as he is a parts reseller. Both are very knowledgeable and thorough in their areas of expertise.

“The car care nut”
https://m.youtube.com/c/TheCarCareNut?ra=m

“I do cars”- this guy is pretty entertaining
https://m.youtube.com/@I_Do_Cars?ra=m

quote:

Originally posted by David Lee:
Black92 why you think it’s anything other than machining debris

Not a professional by any means.

Because engines are failing from both the factory in the United States and Japan. Also the damage seems to pretty much be focused on 2 main bearings in particular.
Machining debris does not discriminate the damage would be through out and not isolated.

They are still having failures on engines produced after discovering the “machining debris issue” they have also since redesigned the #1 main bearings to address the failure issues.
Why would you redesign a bearing that is not flawed and a cause for issue.

I could see them redesigning the block slightly to make cleaning debris easier but why redesign a main bearings??

My uneducated hunch is the bottom end of the 3.4 is simply borderline strong enough to deal with almost 500 lb ft of torque pushing over 5,000# (empty) through 4 main bearings. I figure Toyota will have a new engine for the truck soon.

^^^
I have an idea- how about putting in a naturally aspirated V8 with plenty of ponies and low rpm grunt for towing without engine killing stress? Perhaps one with a positive reputation for power and longevity that could easily fit in the engine bay? Maybe even one that already exists and can be found on the road today easily surpassing 200k miles and beyond easily with regular maintenance? I wonder where they might find an option like this?

^^^^^^^^^^^^^^^^^
While I agree whole heartedly. There are two big things standing in the way of that.

1. Our good friend the government and all their mpg and emissions standards.

2. Sales numbers 2023, 2024, and 2025 were some of the highest selling years for the Tundra ever, even with these trucks being recalled for catastrophic engine failures.
That is beyond mind blowing to me!!!!

I remember V8 Tundra owners always complaining about the abysmal gas mileage and asking "why is it that GM and Ford trucks get such better mileage"? Why can't Toyota do something about it?

Now that all those higher mpg trucks are having premature engine and transmission failures rather than lasting 200,000+ miles like they used to, people are back to wanting durability over an extra 2-3 mpg.

quote:

Originally posted by Black92LX:
^^^^^^^^^^^^^^^^^
While I agree whole heartedly. There are two big things standing in the way of that.

1. Our good friend the government and all their mpg and emissions standards.

2. Sales numbers 2023, 2024, and 2025 were some of the highest selling years for the Tundra ever, even with these trucks being recalled for catastrophic engine failures.
That is beyond mind blowing to me!!!!

Body redesign, lots of new tech, deals on trucks with better than covid results, amazing too that interest rates are up as is the MSRP on everything, average PMT is somewhere over $700 a month!!!! Ludicrous !!

GM implemented a number of things to get better mileage.
Active Fuel Management aka Cylinder deactivation and it is awful drivability and dependability went down the toilet. Bypass/delete that and the motor is actually very enjoyable albeit the 5.3L is a bit anemic. The 6.2L has better low end that rounds out power nicely.

They also added more gears 1st the 8 speed and now the 10 Speed. Both were plagued with problems in reliability and longevity. Though would argue the torque converter was the actual problem. Initially the GMs trans ran way too hot and would cause the torque converter to implode taking the rest of the trans with it. Keeping the temps down helped but if one upgraded to billet components to the torque converter it then was rock solid.

They also use much lower gear sets. 3.23s also help with gas mileage but are real dogs off the line because of it and likely the reason the 5.3L seems anemic.

The 8 speed is a great transmission with an upgraded torque converter and low fluid temps. The 10 speed is just way too many gears.

Toyota was the opposite of all that 5.7L V8 with no cylinder deactivation, 6 speed transmission, and a 4.30 gear set!!!!! 6 speed and 4.30s alone will gobble up mpgs.

Currently own a 2014 Tundra, had a 2015 Suburban, 2015 Expedition, and now also have a 2022 Expedition.

The 14 Tundra is the best to drive, followed by the 2015 Expedition, 2022 Navigator, and 2015 Suburban
Would love for Ford/Lincoln to have the 5.0 Coyote in the Expedition and Navigator. I don’t like 10 speed transmissions as it is always shifting.

The 3.5L Ecoboosts get really good gas mileage on the Highway but abysmal around town. However the longevity of the 3.5s is decent but will have to do cam phaser and turbo work eventually.

If GM would cut the Active Fuel Management, go back to an 8 speed with a billet torque converter, lower fluid temps they would have the most reliable truck drivetrain available. MPGs would go down but not by a huge amount. Bump the gears up at to a 3.55 or 3.73 and the 5.3L would be ideal power wise more most folks uses without feeling sluggish.

Our 22 Navigator has been great. I just don’t like the 10 speeds. I know that it will need Cam phasers and transmission work so I got the warranty until 125,000 miles for less than half the cost of Cam phasers alone.

But back to Toyotas a 5.7, with an 8 speed, and somewhere around a 3.55 gear set would be a nice combo with decent mpg.

As for V8s, Chevy/GM are having huge issues with their 6.2 engine grenading itself. Then there are the issues with 10 speed transmissions across several brands. Add in Jeep just announcing a huge recall for 21 through 25 Wranglers and Gladiators due to them spontaneously catching fire (steering pump overheating and catching on fire). Their fix right now is park it away from house and home and not near other cars. Ford announced a recall for Bronco Sports with the immediate fix of “Don’t drive it.”

I'd say the Dodge truck with the I-6 and ZF transmission is probably the least bad of the 1/2 ton trucks at this point.

As said previously, trust and reputation matter long term. I think Toyota learned their lesson with the frame debacle, eventually doing the right thing. Manufacturers don’t get how important that is, one of KTM’s major blows was the Cam issues on the 790/890 motor. It took on a life of its own and crushed resale value of the bikes involved. I would be lucky to get half of what my 890 should be worth.

Honda had the same sort of issue in 84’, you never hear about that and even at the time it was a non issue. My bike was 2 months and 3k miles out of warranty and Honda replaced all the cams (V4) at no cost to me. It took one call from the dealer and 10 minutes.

quote:

Originally posted by ridewv:
I'd say the Dodge truck with the I-6 and ZF transmission is probably the least bad of the 1/2 ton trucks at this point.

And it's incredibly fun in the new Charger.

quote:

Originally posted by DanH:

And it's incredibly fun in the new Charger.

I bet it is!

quote:

Originally posted by 1s1k:

quote:

Originally posted by David Lee:
Seems like I read, back when this happened, it was a mere 2,000 blocks found to have debris in them, all machined at Huntsville, Al. That said, why they recalled 102,000 vehicles is likely to CYA with the Customers. I know a bit about casting and machining cast aluminum vs cast iron. The cylinder sleeves in this V6 are cast iron. I can see debris causing oil flow restriction and, especially if it is aluminum chips or particals. Enough junk built up and the steel parts begin heat seezing and wear. I would be interested in your further thoughts Black92 why you think its anything other than machining debris. Ive seen Ford engine blocks, here in Florence being dunked in a chemical vat to be cleaned and, Ive fed robots Ford heads in pairs to be machined. Its a stupid job. The bot unloads the 3rd mill, places a pair of heads to be hand deburred by a human, advances the pair from the 2nd mill, to the 3rd, the pair from the 1st mill into the 2nd then, loads the pair I place into the 1st mill. Again, one feels about worthless feeding a robot.

Your theory sounds like it would be the common sense opinion and it’s one that many manufacturers like to use because no one wants to admit to a design flaw. That sounds infinitely worse than some dirt got in there.

The video I posted above answers your question. Basically it is debris causing the problem but it seems to be a possible tolerance issue that causes a problem and then throws debris all throughout the engine.

The reason the guy I posted believed that is because none of the rod bearings had a problem. It’s the end bearings and all of them are oiled by the exact same system as the rod bearings.

I enjoyed that video. IMO, that is the most complex POS V6 Ive ever seen. I too feel like this is a part size tolerence issue mixed with flatness machining tolerence on the deck section housing the main bearing caps. With this sectional engine block design, flatness on both the block bottom and that deck piece housing the main bearing caps must be held to some critical numbers to allow for the bearing caps center line. No longer can they rely on just journal diameters to determine bearing thickness. The damn thing is too many pieces of machined sand castings bolted together. I would never own one.