Hello. I am the 2nd owner of a 2001 4runner 4WD. The original owner owned it up to 100,000. I since took over and used only Castrol oil every three thousand miles, all seals and belts, including timing belt were replaced at Toyota. Engine blew at 135,000. I had an AEM intake on it and thought originally that water might have gone thru to the engine and caused hydro-lock. Probably what happened is that the lady whom I have purchased it from didn't change her oil often, causing premature breakage of the connecting rod.
A few thousand miles before engine failure, I was hearing a tapping sound when accelerating slowly(bearings?) from the speeds of 45mph to 60mph. I put 87 octane in my suv, the manual states it is ok to do so. I accelerate hard on straight aways pushing 100mph, revving at times around 5,000 rpm's. Yes, I do this somewhat often, but I am proud of all my prior Honda's and Toyota's that have never let me down.
In a nutshell, the engine made a loud boom sound when trying to pass a slower vehicle. PLEASE NOTE: THE BOOMING SOUND HAPPENED WHEN I WAS JUST STARTING TO ADD ACCELERATION.
The dealer stated connecting rod blew and put 2 holes in the bottom of my motor.

I have never had a problem with any of my Japanese 4 cylinders in the past, but I must say the 6 cylinders make me skeptical.

Please no emails that I abuse my 4runner, adding gas to the pedal should not be grounds for engine failure.

Bottom line: Possible past poor oil change habits from previous owner followed by Toyota's WEAK parts, rods, rod bolts,etc.

Thanks for listening, take care...Still a 4runner fan...I guess

 

I'm more concerned that you regularly drive your 4Runner at 100mph.

 

from what I've read, the 3.4L is overbuilt. I doubt weak parts are the issue.

it seems toyota's engine designs change dramatically depending on the previous application and initial design criteria. The 2.0L 3S-GTE I-4 engine found in the 2nd gen Turbo MR2s can push 700whp. The 1.8L 1ZZ-FE I-4 in newer MR2 Spyders seems to top out at 250whp before rods break.

 

Oh man I am sorry to here that. But I think everybody here would agree with me when I say you cannot blame the 3.4L motor in 3rd gen 4Runners. They are over engineered and overbuilt because of the lacking previous 3.0L. Every car is different but I have seen many of these motors at well over 300k and running strong.

 

Sorry to hear that your motor gave out on you.. I dont believe that the 3.4L motor is by any means WEAK. There is a number of things that could of happen, Your motor could of just been one that had a little manufactures defect that lead to bigger things. not saying that was a problem with them, just saying that there is by far way way way more toyota motors that make it past 250k before having major problems then blown motors.. usually its other things that lead to their retirement.

 

Im sorry to hear that your engine is toast, but I have to agree with everyone else. The 5vzfe is not a weak engine. The previous owners lack of matenence would contribuite heavily to an engine failure.

p.s 100mph in a 4runner? Why?

 

I'm also sorry your motor took a #2, but really 100mph regularly? it's a truck.

 

sounds like you may need to stick to your honda's doin 100 and passing cars all the time..

 

My 96 is at 200K, doesnt even make a tick. Strong motor, though 1 question we all have why 100MPH? I mean I hit the gas hard (time to time, such as offroading when RPMs kick to 6K when red line is 5500 and the rev limiter kicks in NOTE thats a VERY VERY VERY RARE case when the rev limiter kicks iv done that once or twice) No thoughs 3.4s hold, i tow with mine, offroad w/it, race. I do however use only a synthtic or synthtic blend oil

 

I would MAYBE go 100mph if i was about to $#!t my pants.

 

Haha - agreed!

Sorry to hear about your mishap, I know that would be pretty deflating.

 

Haha, yeah buddy...

I think a concensus has been reached for this thread...

Nice first post though. Sorry for your troubles...

 

I guess the moral of the story is when this happens...
....You need to investigate. You may have been able to get by with $30 in bearings and dropping the pan to swap them out had you heeded the engines cry. I have learned through experience that some lessons in life just cost more than others

 

driving 100mph??? personally i am glad your motor blew. you dont need to be on the road risking everyone else's life that you fly by. it only takes a 1/2 of a mistake to kill people... be prepared to do some jail time if you kill someone going that fast.. jackass

 

It always sucks when your rig does the "wheels up" and you end up with serious repairs. Several issues are being raised here, no need to belabor the "100 miles per hour regularly" issue nor the "weak V6". Maintenance is #1 key, listening to the vehicle when its "talking to you" is #2. Lessons we all learn. I would suggest a Japanese crate motor. Many reliable automotive businesses deal just in such motors and the ones that get sent to the US for these companies are generally excellent, low mile engines. I had one replaced in my 88 Subaru and it was fantastic. Usually they are around 40-80K miles so another 3.4 crate should last longer then you'll probably own the truck. Cost is very reasonable. I guess it would just depend on where you get the motor and who does the work for you. I have a local, reliable mechanic (read that Not a Toyota Dealer) and install of the crate motor in my Subaru (including the crate motor) was around $2500. Motor alone was around $700. so that is an option I think would be worth looking at. Toyota will charge you BIG $$$. Bottom line here is maybe you should re-evaluate your driving style? Just some thoughts. You did come here to post the problem, maybe after reflection the problem may not be just the truck ....

 

I've touched 110 couple of times.

 

Yeah pushing a 2500 lb honda to 100 is one thing, pushing a 5000 toyota to 100 is another. Sounds like you ragged on that motor consistently then wondered why it took a crap.

 

I agree--with all--it is not a sports car--hundred should only come on very special occasions--very--and rev the hell out of it all the time...its not an Acura--it dosnt have the cams nor the breathing ability to do that.

Learn to enjoy just taking your time--let people in--drive like its a low rider--then wheel like you stole it

 

when traveling, if I am on a wide open highway with no one around i sometimes crusie around 90mph. I take my time getting there (not keep it floored until i hit 90)

 

why the hell are yall freaking out about 100MPH??? Ya i know one shouldnt be driving that fast, but big deal 100. im not saying i regularly do that in my 4runner, but i have gotten close, not that scary.

As to the original poster sorry to hear of your troubles man and hopefully you can get in another 4runner or get you another engine for this one.

Also as to mpavolka, the 3.0 bottom end is very strong and overbuilt as well. When have you heard of a 3.0 owner having problems with their bottom end? Not very often. Usually it has to do with the #5 & #6 because of the exhaust and eveything gets too hot back there, pop goes the weasel.