Engine locked up, but didn't throw a rod? Timing belt?

[RunnerPDX]

I've got a 99 4runner with the 3.4, and was accelerating to get on the freeway when "pop" and decent shudder, then dead engine. Thought for sure I blew a rod...BUT no smoke, no leaks, no holes. Tried to start the engine, would not crank over at the least. Seized up. I checked all the fluids, no signs of internal damage. Oil was clean no milkshake, trans was clean...

The only thing I can figure is that it's a blown timing belt. But the 3.4 is a non-interference engine so it shouldn't seize the motor if it breaks, right? Should still be able to crank over...Unless the water pump locked up...but there were no signs of overheating at all.

Anyone break a timing belt on a 3rd gen and have their motor lock up? Any thoughts on what could cause this?

 

[98Base4R]

A locked up A/C compressor or alternator can do this. If it doesn't throw the belt, it can prevent the engine from turning over. Remove the belt and try to crank again.

 

[541joseph]

Rod bearings could've seized due to lack of oil

 

[541joseph]

A locked up A/C compressor or alternator can do this. If it doesn't throw the belt, it can prevent the engine from turning over. Remove the belt and try to crank again.

It wouldn't stop almost 200hp when accelerating to hwy speeds the belts would slip and if the ac pump burned up. The clutch on it will slip and smell horrid

 

[RunnerPDX]

Rod bearings could've seized due to lack of oil

Oil is good, and I recently changed. Unless there is a real sludge problem [which i've heard of] I can't imagine the bearings going out. The engine ran smooth and quiet...no signs of knock, grind or other issues. T-belt was done back at 98k it has 149k on it now...so it is due [but within range]...

I'm going to dig in today and see what i'm dealing with...

 

[KidVermicious]

I've got a 99 4runner with the 3.4, and was accelerating to get on the freeway when "pop" and decent shudder, then dead engine. Thought for sure I blew a rod...BUT no smoke, no leaks, no holes. Tried to start the engine, would not crank over at the least. Seized up. I checked all the fluids, no signs of internal damage. Oil was clean no milkshake, trans was clean...

The only thing I can figure is that it's a blown timing belt. But the 3.4 is a non-interference engine so it shouldn't seize the motor if it breaks, right? Should still be able to crank over...Unless the water pump locked up...but there were no signs of overheating at all.

Anyone break a timing belt on a 3rd gen and have their motor lock up? Any thoughts on what could cause this?

If you'd broken a timing belt it would crank faster than normal without starting, not fail to crank. Are you sure it's seized though, it sounds like you're trying to turn it over with the starter? Get a breaker bar and try to turn it over at the crank pulley bolt. If you can manually rotate the motor, it isn't seized and you've got something else going on.

When I threw a rod through the block a couple years ago, I didn't lose any oil. And there's ways to seize the motor without putting a hole in it anyway. So just because you have oil doesn't mean you don't throw a rod or lose a bearing. But first verify that the motor really is seized.

 

[RunnerPDX]

If you'd broken a timing belt it would crank faster than normal without starting, not fail to crank. Are you sure it's seized though, it sounds like you're trying to turn it over with the starter? Get a breaker bar and try to turn it over at the crank pullet bolt. If you can manually rotate the motor, it isn't seized and you've got something else going on.

When I threw a rod through the block a couple years ago, I didn't lose any oil. And there's ways to seize the motor without putting a hole in it anyway. So just because you have oil doesn't mean you don't throw a rod or lose a bearing. But first verify that the motor really is seized.

Will do!

 

[LittleCaesar]

Put a 19mm on the crank bolt and try to turn it as Kevin suggested. Or a compression test would work as well.

My friend once had a flywheel literally go and implode on him once outside of Flagstaff AZ pulling a trailer. It sheared into four pieces. However, it was a Dodge.

 

[the great him]

A locked up A/C compressor or alternator can do this. If it doesn't throw the belt, it can prevent the engine from turning over. Remove the belt and try to crank again.

yeah no, the AC pump would have exploded or the clutch would have disintegrated, and yeah the belts would have simply snapped if either of those ideas had happened. there is no way that either of those would have shut down a motor as described.

it is possible you broke a rod, and it didnt punch through, but there should have been some rattling/knocking as the motor shut down associated with this. have you checked the main power fuse? it could have blown, and that could have caused your motor to shut down, and the lack of spark/electrical power could have cause the rough idle-down till dead, and not allow the motor to turn over. you could have a short some where in the charging system, and under a large load, like hard acceleration -especially if you had lights, radio on ect could have exposed that weak link and popped the main fuse or charging fuse. -im gonna guess this is the cause of your issues.

 

[amalik]

If you'd broken a timing belt it would crank faster than normal without starting, not fail to crank. Are you sure it's seized though, it sounds like you're trying to turn it over with the starter? Get a breaker bar and try to turn it over at the crank pulley bolt. If you can manually rotate the motor, it isn't seized and you've got something else going on.

When I threw a rod through the block a couple years ago, I didn't lose any oil. And there's ways to seize the motor without putting a hole in it anyway. So just because you have oil doesn't mean you don't throw a rod or lose a bearing. But first verify that the motor really is seized.

When turning over the engine manually, do you have to remove the upper radiator hose and timing belt cover? Not seeing how you would get to the bolt without doing that?

 

[JRZEE2000TR4LTD]

Take the skid plate off and get it from the bottom

 

[BlackCat914]

Put a 19mm on the crank bolt and try to turn it as Kevin suggested. Or a compression test would work as well.

My friend once had a flywheel literally go and implode on him once outside of Flagstaff AZ pulling a trailer. It sheared into four pieces. However, it was a Dodge.

How do you do a compression test on a motor you can't turn?

 

[TheDurk]

It's rare, but a Timing Belt CAN lock up an engine if the loose end gets jammed into another component. A peek behind the cover can clear up a lot here.

 

[twitchee2]

My buddy had some debris, don't remember what it was, get caught in the flywheel and it was "seized" but nothing was wrong with the motor. Just wouldn't crank over. Sounds like you have something like that happening.

 

[LittleCaesar]

How do you do a compression test on a motor you can't turn?

Nothing worse than being on two forums and answering the question incorrectly on the wrong forum. Just a part of being a dumb ass sometimes....

 

[Bigdogyj]

I know this is an old thread but noticed there was no closure to it. Anyone know what happened? I have a 2000 with 220k that is experiencing the same exact symptoms. Died on highway, will not crank over. Unable to crank by hand with spark plugs out. Timing belt in good shape. No signs of contaminated oil or coolant. No overheating or anything. Well maintained vehicle.
If anyone has any other ideas. I’m about to pull the oil filter and look inside but I’m worried it’s something catastrophic internally. It’s just weird that there were no odd noises or shutters or anything. Just cruising at 70mph engine shut off and coasted to the shoulder.
Thanks.

I've got a 99 4runner with the 3.4, and was accelerating to get on the freeway when "pop" and decent shudder, then dead engine. Thought for sure I blew a rod...BUT no smoke, no leaks, no holes. Tried to start the engine, would not crank over at the least. Seized up. I checked all the fluids, no signs of internal damage. Oil was clean no milkshake, trans was clean...

The only thing I can figure is that it's a blown timing belt. But the 3.4 is a non-interference engine so it shouldn't seize the motor if it breaks, right? Should still be able to crank over...Unless the water pump locked up...but there were no signs of overheating at all.

Anyone break a timing belt on a 3rd gen and have their motor lock up? Any thoughts on what could cause this?

 

[96RedRunner]

It is catastrophic if you can't rotate crank with breaker bar you're just delaying the pain.
Filter check easy enough, out of curiosity I'd wrap it with good layer of painters tape cut it with
what ever saw or cutoff wheel.

 

[Twisted Sid]

It is catastrophic if you can't rotate crank with breaker bar you're just delaying the pain.
Filter check easy enough, out of curiosity I'd wrap it with good layer of painters tape cut it with
what ever saw or cutoff wheel.

No, taping it won't stop the swarf from going into the filter. That's why they make oil filter cutters. It cuts like a pipe cutter or can opener and doesn't remove material.

 

[alumarine]

You could pull the plugs and use an inexpensive boroscope to check the pistons/cylinders.
https://www.amazon.com/s?k=borescop...efix=borosc,aps,105&ref=nb_sb_ss_ts-doa-p_2_6

 

[Devbot]

If it was catastrophic, you would've heard it