My beloved 02 Xterra with 200k miles on it just had a timing belt break on the highway. It just died immediately when I got to the top of a hill. The mechanic--who I know to be trustworthy-- said it depended on if the valve(?) were bent if it would cost a little or a lot. He can't get to it for a week though. Wouldn't it have made a horrible noise if a valve got bent? It just died, no racket or knocking, just stopped. I will worry myself to death by next week. What can you tell me? ;0(

The 3.3 V6 engines we have are known as "interference" engines, meaning that the valves and pistons will get in each others way if they aren't controlled. And that's the purpose of the timing belt - to keep the timing of the two separate so that doesn't happen.

Sometimes if you're not under any load, the belt can break and the engine just stops. Other times, if there's momentum, the pistons and valves will get in each others way and some serious damage can occur. That's why your mech can't tell you until he tears it down and looks at it which category you fall. If you were at the top of a hill, depending on if you were at the top or just getting there or starting down the other side, you may or may not have been under load. In any case, you could be looking at some damage. But then again, maybe, maybe not. "Do you feel lucky? Well, do you?" (Sorry for the Dirty Harry quote.)

There is one easy way to have prevented this - change the timing belt on schedule (every 105k miles or 7 years). My truck is an '03 and has just 54k miles on it as I only live 3 miles from work. BUT, it's going in probably the end of next week for its first belt change. And I'm at least 2 years overdue. 200k, well, that was just plain asking for it to break.

We all hope yours turns out to on the lesser damage side of things. Plan on it being at least a $1k though as the belt change under good conditions is $800-$1k.

One other thing you should have done. While he's in there, have him replace the other items that require the same tear down to replace - water pump, thermostat, drive belts, etc. That way you save on labor (he'll be putting in new parts instead of the old ones that could then break) and you end up with a more reliable truck.

Fingers crossed for you!

-G

If the timing belt broke while traveling at highway speed you can count on bent valves, that's the bottom line.

If it happed at idle , you'd have a better chance at no damage.

It's going to be expensive to fix so save up.

Sorry about your luck.

Well you guys are just cherries on top of my ice cream sundae kind of day!!!! I guess we will see. My husband said that if it did bend a valve then when the mechanic fixes it, and replaces the valves it will be good for another 100K miles so I guess that will be good. I was at the very top of the hill, probably coasting towards a stoplight that is there, not gassing it, It just quit and I pulled it to the side of the road. I was probably going 40 mph when it died. I know I know I know that I should have replaced the belt a long long time ago, but well... I didn't. I did tell the mechanic to replace all that other stuff when he gets it all torn apart. I will let you know what he says and how much it costs me when I hear from him.

Oh My Gosh you guys. I'm thrilled to report that as luck would have it, the valves were not bent once the mechanic got the timing belt fixed. He put on a new clutch fan and the other stuff and the total bill is $310 plus tax.

cheap mechanic!

Yes, he told me to put a little extra in the donation plate at Church to thank the higher power that the valves weren't bent or it would have cost us a lot more. Apparently a bunch of teeth (?) got sheered off of the belt at the bottom, I saw it and yes, the belt was in pretty rough shape. The mechanic said it looked like it had never been changed (remember I have 200k miles on this Xterra!) I am very happy with this old-school mechanic and will certainly go to him from now on.

Cheap indeed. I just got my truck back yesterday afternoon from having my timing belt (water pump, thermostat, drive belts, etc.) changed. Total cost: $816.37. Not a bad price from what I've heard, but it was also done by my local Nissan mech too.

Two things - 1. You were VERY lucky for not having any bent valves. And for the price, I'd question how well he looked. But if it runs OK, so be it.

2 - Let this be a lesson to all - 200k miles and not having it changed was ASKING and maybe even PRAYING that it would snap! Get it changed BEFORE it snaps to avoid the VERY HIGH likelihood of major damage!

Again, you were incredibly lucky. Good for you. But I just hope others that read this don't think they could be that lucky. Proper preventative maintenance is important!

Well, today is the day I should be getting the news from my mechanic on the extent of the damage on my broken timing belt.

:-(

Hopefully the good thing I have going for me is that I drove it and it was running normally, parked it, shut it off, then an hour or so later when I tried to start it again it wouldn't.

The timing belt apparently broke when I tried to restart it, it didn't even fire up even for a little bit.

Time will tell . . .