I was driving to work this morning when about the worst thing that could possibly happen, happened. The engine just died. So I pulled to the side of the freeway, called a buddy to have him come pick me up, and then I took a closer look at the engine. What did I see? Part of my timing belt poking out the bottom of the cover.

A little history: Its a '91 3.0 with 169k miles. I bought it about a month ago with a blown headgasket and a bad clutch. So I just finished with all of the work on it about a week ago and I've now put about 5 or 6 hours of driving on it since.

After work tonight Im going to dive into it and fix it, but now Im sitting here trying to think of what may have caused it to break. The belt had been replaced by a shop at 140k miles so I didn't replace it when I did the headgasket. Its condition looked good when I had it exposed doing the engine work. Im wondering now if I put the camshaft sprockets on backwards. I remember that one side of the sprocket has a lip on it and the other side doesn't. When I put them on I made sure that one lip was towards me and one was away from me, but I didn't know if the lip on the outside needed to be on the right or the left camshaft. Does it matter?

 

didint hurt any thing when it broke

 

As far as I can tell, no.

 

the water pump is seized up you must replace the water pump when you do the belt or this is what happens, you should replace the tensioner also so you don't have to do this again.

 

But does it matter how the camshaft sprockets are situated on there?

Angus, you said to replace the timing belt tensioner? Its just a spring. Are you supposed to replace the spring?

 

My manual shows the driver side with the lip towards the front and the passenger side towards the engine. If you have them reversed it might be a good idea to swap them when you replace the belt. I don't know if that caused it to break though. Make sure you check the idler pulleys, and replace any that aren't very smooth and quiet.
Also, too late now I know, but it's never a good idea to reuse a timing belt.

 

I asked the dealer that when I replaced my belt and they said they never replace the springs, in fact none of the dealers in this area even stock them or had sold any.

 

my tensner was hydraulic i forgot the older ones were just springs. The problem is most likly your water pump people dont replace them when they do the belt and later down the road it goes and smokes the belt.

 

Cant hurt to check with the shop that replaced it last and see if they have any type of warranty.

 

I'm pretty sure timing belts(no matter how new) are a 1 time use. They have a lot of strain put on them, so once you take them off, you are supposed to replace them. Not sure if this is the reason why it broke, but being retorqued probably didn't help.

 

I was doing a little research on timing belts and I think I just figured out why mine broke. So when I had the heads off I didn't take the crankshaft pulley's off and so the lower timing belt cover stayed on. I replaced the clutch while the heads were off and while my buddy was attaching the new clutch to the flywheel I was holding the crankshaft with a wrench and turning it to the different bolts. Now, I just barely remembered that at one point when I was turning the crankshaft the timing belt had doubled over itself and jammed down in the lower cover, kind of pinching itself. After I realized what happened I backed it out and forgot about it. But, when it pinched down in there it must have broken the little reinforcement fibers in the belt, thus causing it to break after about 50 miles of driving. So moral of the story I guess: ALWAYS REPLACE THE BELT WHEN DOING ENGINE WORK AND YOU TAKE IT OFF THE CAMSHAFT SPROCKETS. Just like many of you have said.

Thanks all!