timing belt broke

4

4runnerlife

New member
hello guys, as it turns out the car wouldn't start because the timing belt has broken while i was driving.
is there anything i need to do when installing a new one? does it effect the valves?? or any other thing you can think about or you just install the new one and thats it?
much help is needed, thank you guys
 
Register to hide this ad
If a timing belt breaks while you were driving it could have caused some serious issues with the motor internally. What I would do is get a new belt, install it and do a compression leak down test to see if you have further issues. This test will allow you to diagnose whether the valves are still seating properly. If there is a large variance in the PSI then you have a bent valve and must pull the heads. Just because this test shows good PSI though doesn't mean you're out of the woods yet. A valve could have tapped the top of a piston and caused damage.

You can pick up a compression tester at your local auto parts store usually for rent.
 
The 3.4 is a non interference engine so there will be no damage to the valves or pistons if the timing belt breaks. You will just have to get the valve timing reset and install the new belt. It is recommend to do the Timing belt, water pump, drive belts, thermostat, tensioner, idler, camshaft seals, and crank shaft seal all at the same time.

Just curious, How many miles do you have on your 4Runner?
 
The 4runner is a non-interference engine so you are lucky. Just line up the timing marks and you should be okay.
 
Since we are on the timing belt question, has anybody replaced their own timing belt, pump etc. and then taken it someplace to actually get the timing tuned in correctly? (Not sure if I used the correct term)
 
steezemcqueen said:
The 3.4 is a non interference engine so there will be no damage to the valves or pistons if the timing belt breaks. You will just have to get the valve timing reset and install the new belt. It is recommend to do the Timing belt, water pump, drive belts, thermostat, tensioner, idler, camshaft seals, and crank shaft seal all at the same time.

Just curious, How many miles do you have on your 4Runner?
Click to expand...


Didn't know that! Good to know! Sounds like you are in luck then.
 
WrexHAmm said:
Since we are on the timing belt question, has anybody replaced their own timing belt, pump etc. and then taken it someplace to actually get the timing tuned in correctly? (Not sure if I used the correct term)
Click to expand...

To advance or ret@rd the timing? I believe its an automatic type thing in the 3.4L. You can just use a timing light on the crank pulley to check though.
 
WrexHAmm said:
Since we are on the timing belt question, has anybody replaced their own timing belt, pump etc. and then taken it someplace to actually get the timing tuned in correctly? (Not sure if I used the correct term)
Click to expand...

Baja Runner said:
To advance or ret@rd the timing? I believe its an automatic type thing in the 3.4L. You can just use a timing light on the crank pulley to check though.
Click to expand...

Somebody is confusing valve timing and ignition timing. The timing belt only effects valve timing and the only way to ensure correct valve timing is to install the timing belt correctly. There is no plus or minus adjustment, although you might have it off by a whole tooth on one or both cams. Again, just check your timing marks. Rotate the crank twice and do it again to be sure.

As Baja Runner said, IGNITION timing is set by the ECU. It is not affected by the timing belt.

As to the original question, there should be no internal damage to the valves. As belt failure is extremely rare even at high miles, the OP needs to check all components for leakage or mechanical failure. Usually something such as a seized idler or leaky water or seized water pump will CAUSE the belt failure. Since this motor was probably neglected, I agree with Steezemcqueen that replacing all components is the best way to go here. Start fresh.
 
Last edited:
what's the mileage

I've been putting off changing my timing belt for a while now and I'm at 175,000. What mileage were you at when it broke?
I wasn't worried about mine breaking because it's a non-interference engine where no damage can really be done.

As far as timing, it's electronic ignition. You can't adjust the timing like you can with an old engine with an actual distributor.
 
Thank you to all you wonderfully people that answered my question, sorry I didn't reply earlier as I was all day under the hood fighting the timing belt :)
To answer your question I have $275000 miles on it.
The timing belt didn't had any wear and tear to it (beside where it snapped) which is a bit strange, I have check the bearings etc and all seems to turn smooth, the only thing that is not smooth is right cam pulley which is very hard to turn with a wrench (compare to the one on the left) any idea of why it's so hard to turn? Could this be the problem?
Someone said that it could loaded or unloaded... Which I don't know what it meens
Maybe you guys do
Thanks again
 
4runnerlife said:
Thank you to all you wonderfully people that answered my question, sorry I didn't reply earlier as I was all day under the hood fighting the timing belt :)
To answer your question I have $275000 miles on it.
The timing belt didn't had any wear and tear to it (beside where it snapped) which is a bit strange, I have check the bearings etc and all seems to turn smooth, the only thing that is not smooth is right cam pulley which is very hard to turn with a wrench (compare to the one on the left) any idea of why it's so hard to turn? Could this be the problem?
Someone said that it could loaded or unloaded... Which I don't know what it meens
Maybe you guys do
Thanks again
Click to expand...

275,000 miles. No way I'm changing it at 90k intervals now. Glad things worked out!
 
hard to turn

If the one side is in the compression cycle it will be hard to turn as the valves are all closed. It's a little strange that they both aren't like this as usually when the belt breaks, this is how both sides like to end up as the valve springs are constantly pushing to get it into this position.
When you do the belt, just make sure all 3 of the marks are aligned and you should be ok.
 
Replaced mine by myself. Took about 10 hours from start to finish. Cost was about 300 dollars in parts alone. If I had help, it would have gone much faster. Was a learning experiance.
 
freshley said:
If the one side is in the compression cycle it will be hard to turn as the valves are all closed. It's a little strange that they both aren't like this as usually when the belt breaks, this is how both sides like to end up as the valve springs are constantly pushing to get it into this position.
When you do the belt, just make sure all 3 of the marks are aligned and you should be ok.
Click to expand...

Yep. You could remove all the plugs from the engine and then both cam pulleys should turn relatively easily. If one doesn't, then you definitely have a problem.
 
All he's turning is the cams. Opening and closing valves... He's not turning the crank so the pistons are not moving. How can there be compression...? Am I missing something?
 
kball said:
All he's turning is the cams. Opening and closing valves... He's not turning the crank so the pistons are not moving. How can there be compression...? Am I missing something?
Click to expand...

No, you're absolutely right. Dumbest post I think I have ever made.
 
You must log in or register to reply here.

Similar threads

M
Timing belt life
Replies
7
Views
348
71gs3504sp
71gs3504sp
B
Tapping/Knocking Noise
2
Replies
28
Views
5K
Blacktower
B
G
Crank and Cam off - Timing Belt issue
Replies
1
Views
2K
rdruss
rdruss
calimobber
Valve Adjustment Gain Anything?
Replies
11
Views
3K
phattyduck
P
K
FS 3rd Gen 4R Limited 4x4 $12,500 Northern Alabama
Replies
0
Views
901
Kokomodo
K

Members online

Total: 241 (members: 1, guests: 240)

Forum statistics

Threads
278,309
Messages
3,554,071
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top