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Discussion Starter · #1 ·
I apologize in advance if this is answered somewhere else. Also I have very limited knowledge of auto mechanics as I work in IT.

1994 Mazda MX6 LS V6 (completely stock)

Timing belt snapped this morning, I was wondering if this was a part worth replacing in these motors: does it generally ruin the valves or damage any other part when this happens.

1. I was accelerating to 45 (probably at 30ish when snapped)
2. Tach was jumpy for about 5 seconds and then went to zero
3. I have not tried to start the car or turn the motor over or anything however it does seem like it ran for 5-10 seconds after the tack went jumpy and before it died completely

I know every problem like this is not really board fixable, I am just asking if in general does the timing belt snapping while driving cause other issues.

Any responses are helpful and thanks in advance.
 

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When mine broke while driving it did not cause any problems but if you are unsure you can always take it to a mechanic to check things out in the head.
 

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Our V6 engine is non-interference. If the timing belt breaks, there will be zero damage to any other parts. The valves will not hit the pistons. (It's not like some other engines).

We know this for sure. Proof: http://mazda626.net/topic/22749-v6-non-interference/ (The Mazda MX6 and 626 V6 are identical engines). Plus, nobody has EVER reported valves hitting pistons when the belt breaks (or they removed it), either on this board, or Mazda 626 or ford Probe boards.

Just replace the timing belt, and timing belt tensioner, and maybe replace the water pump and idler pulleys while you are in there.

But, there's a significant chance your distributor died, rather than the timing belt snapping. (This is a common problem, and has roughly similar symptoms, including the tachometer dropping to 0rpm quickly). Try to start the engine. If it starts you know it wasn't the timing belt, and was very probably the disty. If it doesn't start, open the oil filler cap, and watch the cam gears while someone tries to start the engine. If the cam gear doesn't turn, you know the timing belt has snapped. Or, just remove a couple of those little bolts from the timing belt cover, pull the cover back an inch, and peek inside.
 

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Discussion Starter · #4 ·
The V6 engine is non-interference. If the timing belt breaks, there will be zero damage to any other parts. The valves will not hit the pistons. We know this for sure. (It's not like some other engines).

Just replace the timing belt, and timing belt tensioner, and maybe replace the water pump and idler pulleys while you are in there.

But, there's a significant chance your distributor died, rather than the timing belt snapping. (This is a common problem, and has roughly similar symptoms, including the tachometer dropping to 0rpm quickly). Try to start the engine. If it starts you know it wasn't the timing belt, and was very probably the disty. If it doesn't start, open the oil filler cap, and watch the cam gears while someone tries to start the engine. If the cam gear doesn't turn, you know the timing belt has snapped.

Thanks for this answer.

Two things, I replaced the distributor a few months ago and also the timing cover is missing 1 bolt that snapped off when I was doing valve cover gaskets so I can actually see that the belt is broken and off the gear.

Thanks again for your answer it took a little bit a worry off of the situation.
 

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Yea I've busted 3 of them on different cars 2 mx6s and a mx3 and actually the last one I popped I did it at 7000rpm and it did nothing like homeboy said these motors are non interference motors, I'd get a new timing belt and tensioner and throw them on, that's one of the reasons I love kl's
 

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Yup. like everyone has said, just replace it. and if you havent already, toss a new timing belt tensioner on also. as those are very failure prone.

Id also recommend finding a local on here that is very familiar with these engines, and pay them to do the job. Our motor isnt a hard motor to work on, but ive seen any shops do more damage then good when working on these. So find someone that has experience working on it if you want things to go smoothly and have no surprises.
 

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If you have the time and patience, and tools, and don't need the car right away, you
can fix it yourself.

I took my car to a shop to replace the timing belt tensioner once. It came back messed up. They had to do it over again.

After that, I try to do everything myself. Now I'm at 200k miles.
 

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Yea I would suggest going to Autozone and buying the Haynes Manuel and doing it that way that's how I learned to work on these cars about 10 years ago now I can tell you anything about it, it should take you 4-5 he's if you do it your self the hardest art is getting the water pump pulley off which I would recommend u take off the bolt with the belt still on and turn the motor over by hand until u get all 4 bolts out and then when u set the timing its a good idea to have somebody there to help hold the came in place while u put the timing belt on
 

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My V6 2.5 Mazda back cam shaft jumped the timing mark even if I try to rottet it it goes off timing marks so I dnt know the problem it also snapped the belt while waz driving
 
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