my 5vzfe blew up

[bwd]

Hi all. New here, coming for a little advice, hope that's ok. Too bad I must start off on a down note here, but:
The other day I was headed out to dinner driving my 99 4runner, when things went awry...

First, background:
Motor is 5vzfe, 4wd, manual trans, 115k miles, timing belt and water pump replaced 6 months ago, last oil change 2 months ago. Motor has been strong, smooth and previously trouble free. Has had regular service, 95% use on paved roads and only low speed towing of a light boat (under 1000lbs) that goes 1/2 mile to and from an easy paved ramp maybe 8 times a year...

Ok, back to the demise of my motor...
I left home, drove 1/2 mile through residential streets at 20-30mph, stopped at a red light. When it turned green, I accelerated with a bit of vigor. Did not floor it, maybe 80% throttle. No wheelspin, no racing, no horsing around -just took off smooth and gave it a plenty of gas. For fun.
1/2 block later, there was a loud "bang."
The tachometer was at 4500 rpm, I was about to shift into 2nd gear. Honestly don't remember if I had hit the clutch already.
No funny noises, no vibration beforehand, nothing. Just a loud bang, violent shaking and smoke/steam/oil shooting out everywhere. I coasted down the block and turned into a side street. Motor was still running. Cut the motor and parked it.
Looking underneath I could see where oil and coolant are streaming out from somewhere under the exhaust manifold, behind the motor mount. Not good.

Seemed only one cylinder was affected, so I have been thinking, must have had an oiling problem, or a valve dropped? Or have there been bad pins or connecting rods in these motors? That would seem so weird, the motors have such a good reputation....

Anyway I would be gratefull for any insight/speculation on what likely happened. Once the motor is out, I will post what I find.

Also welcome any recommendations on sourcing 5vzfe's and on mechanics in Richmond or central Virginia, US. Would be fun to think of swapping motors or upgrading the v6, but really I will probably be happy to get back what I had, just a great everyday vehicle.
Thanks.
-bwd

[enormis]

WoW! Did you see a hole in the block or what? Hole in the oil pan? That is completely rare! I am a former auto tech and have about six vehicles in my immediate family with that engine.(I have a 99 runner and 97 taco as well) I take care of all of them- as far as maint. etc. One is a t100 with 275 abusive miles on it! No leaks, no drips, no oil consumption at all! I also have seen them hit three hundred k, and keep going! So ,for something to just let go like that is RARE! I can't tell you how sorry I am for you! That sucks! Good thing is that these are the easiest vehicles to work on that I have seen, I think you should be able to pick up a bone yard engine for a lil over a grand complete! Just get a new clutch and transfer your t-belt and newer parts to it and slam that bitch in! Still, probably that last thing you wanted to deal with right now... Curious to know what really happened keep us posted! :headscratch:

[bwd]

Couldn't see a crack/hole- tried using a mirror but it was too dark in there. Car is still on the street, will tow it tomorrow. When it happened though I could definitely see the source of oil/water was up right under the manifold, not down in the pan, so I am thinking piston/valve unhappiness. We'll see....

[DHC6twinotter]

Is it leaking between the block and head? Head gasket maybe?

The 3.4s are fine motors...I wouldn't replace it with something different.

[bwd]

Gasket? I guess it could be? That would be preferable I guess.
But the "bang" and horrible shaking have had me thinking reciprocating parts were flying around in a bad way....
Overall the experience reminded me of NASCAR, only lucky for me the speed was about 140mph slower -laid down quite a stripe of oil.

[4runnerchevy]

The bang and horrible shaking sounds like your piston making contact with a valve. I might rule out timing belt, since you changed it, but making sure its not broken would be one step. A broken timing belt could cause your conflict between the valve and piston (even more when your 80% throttle). It could also be a bad day at the Toy plant, everyone has em'.

[traben27]

The bang and horrible shaking sounds like your piston making contact with a valve. I might rule out timing belt, since you changed it, but making sure its not broken would be one step. A broken timing belt could cause your conflict between the valve and piston


I almost had that scenario happen when I was about 1/2 mile from my mechanic after he had replaced the timing belt, but luckily it retarded the timing instead of accelerating it. Towed it back to him and it turns out the head on some random bolt sheared off and caught between teeth of the belt and made it jump. I got lucky that day haha.

Bump for help

[BruceTS]

Sounds like you busted a rod and you'll probably find a cracked block. If the rod snapped off near the crank, the engine will keep running.....

[20005spd]

this is probably rare in this engine, but maybe the t-belt tensioner pulley seized which caused the engine to jump time and slam valves into pistons

[DHC6twinotter]

Somebody correct me if I'm wrong, but I'm pretty sure the 3.4 is a non-interference engine. So if the timing belt breaks or jumps teeth, it won't cause the valves to hit the pistons.

[oly884]

Somebody correct me if I'm wrong, but I'm pretty sure the 3.4 is a non-interference engine. So if the timing belt breaks or jumps teeth, it won't cause the valves to hit the pistons.


I was just going to say the same thing. I thought the 5vzfe was non-interface as well.

If the head gasket went, it could have sent coolant into one of the cylinders and when it went to compress it, it didn't, and hence the loud bang, coolant and oil everywhere.

[YotaFun]

Somebody correct me if I'm wrong, but I'm pretty sure the 3.4 is a non-interference engine. So if the timing belt breaks or jumps teeth, it won't cause the valves to hit the pistons.


I was just going to say the same thing. I thought the 5vzfe was non-interface as well.

If the head gasket went, it could have sent coolant into one of the cylinders and when it went to compress it, it didn't, and hence the loud bang, coolant and oil everywhere.


The 3.4L IS a non-interference engine.

I was thinking the same thing oly.

[bwd]

Got it checked out by a good shop. And yes, block is cracked, but that's all I know so far.
But the shop would only do a Jasper, essentially, since he doesn't have a source he knows and trusts that has a 5vzfe now.
The estimate is killing.
Mainly it's that clever oil cooler that kicks it up another $655 beyond reason. Misery.
Such a brilliant design that cooler. Grrrr. :shake:
Any oil coolers fall off a truck I should know about?
Other advice? Thanks.

[oly884]

Got it checked out by a good shop. And yes, block is cracked, but that's all I know so far.
But the shop would only do a Jasper, essentially, since he doesn't have a source he knows and trusts that has a 5vzfe now.
The estimate is killing.
Mainly it's that clever oil cooler that kicks it up another $655 beyond reason. Misery.
Such a brilliant design that cooler. Grrrr. :shake:
Any oil coolers fall off a truck I should know about?
Other advice? Thanks.



A Jasper? What is that?

Also, what's up with the oil cooler?

If you were to hop over to yotatech you'd find a few threads about me and my old '90 pickup and the unfortunate event of a connecting rod snapping in half.

It sucks, but I searched online for a company that rebuilds engines and managed to find a reputable place out of new york. Shipping sucked, but oh well. Another option is picking up a junkyard engine and a rebuild kit and go to town.

[slosurfer]

Jasper is a company that sells reman. engines.

A new oil cooler is usually required by a company on a new reman if you want to get a good warranty.

[oly884]

Thanks Chris for clearing that up!

[20005spd]

i thought it was an interference engine. o well, i work on nissans what the hell do i know :D

[Trevor]

order a new one from japan

[bwd]

Well, new motor's in. Old one's out. Still not sure why it blew.
I might have run it a little hard, but not ridiculously, and kept up with the maintenance. No serious offroading, drag racing .... New motor came from Jasper, and it runs fine. As it should at the price. Ouch.
Anyway, the oil was clean, and I saw no leaks before it blew, no knocking or other noises, nothing to clue me in. Just went. I am choosing to blame the rod bolts. Whether they were the first thing to go, I can't say. But as you can see, they did break....
I should add, the previous owner was a state trooper, whose dad raced cars.... :headscratch: So whatever they did to it, may have taken its toll.
Pictures for your entertainment: