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95 mazda mpv timing belt keeps shredding


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chloemiller
Novice

Feb 3, 2011, 9:34 AM

Post #1 of 17 (6937 views)
95 mazda mpv timing belt keeps shredding Sign In

have a 95 mazda mpv. 3.1 v6 engine 2 wheel drive, automatic transmission. I replaced the timing belt recently I had to do it a few times to get it right. I was driving it for 2 months about 30 miles a day or less. One day when i was about to go to work, it sounded funny and looked under the hood, i saw fiber glass (I think?) all over the place, and noticed the timing belt was shredding. The cover doesn't fit tight against the engine in one spot, so i can see in there. I had replaced the belt, water pump and the hydraulic tensioner.

So when i took it apart to try and figure out why it was shredding, I thought it was because i didn't replace the pulleys. so i bought a set along with a new belt and put it together. drove it for about 2 weeks, and was on my way to miami, the van stopped accelerating on the interstate, the check engine light went on, soon after that all over lights went on too (fuel, oil, battery, ect.) i pulled off and have been having a hell of a time getting it towed back here 250 miles away.

I'm assuming my belt broke. I looked in there and the belt is shredding again, but it hadn't shredded much yet, not like the first time. But, it really seems like it broke. Ive read that this engine is both interference and free spinning. So, im crossing my fingers that its the latter. I am going to do tests to make sure the valves arent bent. ( not sure if this means anything, but when i broke down, it was very smooth and i heard nothing. no banging or clanking)

But now im so confused about what the hell is happening. heres my leads....

one of the times i was installing the belt, i accidentally stripped some threads out of the engine where the upper idler pulley goes. i drilled it out carefully and installed the proper helicoil. put it back together and it ran fine for 2 months until that day i noticed the fiber glass. the hole i drilled seemed pretty effin straight, but, im wondering if i drilled it a little bit crooked, if that could be causing the problem.

i also did not have a torque wrench, there are specific torques for all pulleys and the tensioner, im wondering if i tightened these things down too much, esp. the tensioner and tension pulley, then they would not be working correctly. seems to me, that is i tightened the tension pulley too much, it would keep the belt too tight and that could be the reason why it broke, but it still doesnt explain to me why its shredding. i do know the reason its shredding is because it slides too far in, and rubs against the engine. any help is majorly appreciated, i can not afford a mechanic at all. Thanks


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 3, 2011, 9:46 AM

Post #2 of 17 (6928 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

There is no 3.1 engine, only 2 different 3.0 engines and they are both interference so it is very likely that you have valve damage. You would have to perform a leakdown test on each cylinder to determine if that is the case or not.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chloemiller
Novice

Feb 3, 2011, 9:51 AM

Post #3 of 17 (6923 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

i thought it was 3.0. someone tricked me to thinking it was 3.1. I planned on doing a leak down test, to see.
lets just say there is no valve damage.

why is my timing belt shredding?


(This post was edited by chloemiller on Feb 3, 2011, 9:52 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 3, 2011, 12:08 PM

Post #4 of 17 (6915 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

That's not something you're going to find the answer to online. Something was overlooked or done wrong and that needs to be physically found.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chloemiller
Novice

Feb 3, 2011, 1:43 PM

Post #5 of 17 (6912 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

im not really looking for THE answer, just looking for some opinions on the two "leads" i have. I'm wondering what people think about my helicoil theory, and the not having the tensioner and tension pulley tightened to the right torque.

I am new to auto mechanics, and I think having a second opinion on things really helps me make decisions. I don't ever think ill get THE answer off the internet when it comes to fixing your own car, but, i have found that after reading several message boards for hours, ill have new ideas, better understandings, and the like.

what do you think about not having the pulleys at the right torque? i tried to make a knowledgeable guess on hand tighening it. COULD it being too tight cause a brand new belt to break? or cause the belt to slide and derail?


Hammer Time
Ultimate Carjunky / Moderator
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Feb 3, 2011, 5:07 PM

Post #6 of 17 (6908 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

A trained eye could probably tell you right away what the problem is. Belts shred because pulley don't align correctly or they lean, causing the belt to migrate right off the side of the pulley. If the tensioner loosens for any reason, the belt can jump a tooth.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



re-tired
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re-tired profile image

Feb 3, 2011, 7:50 PM

Post #7 of 17 (6904 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

A trick thats worked sometimes on some engs. Get an old fashioned wooden yardstick . place it on edge on two pulleys at a time . any pulleys not square with the stick is a problem to be checked. common failures are , a bearing going bad, tensioner failure , try to move each pulley up and down ,esp waterpump , new parts can fail. make sure the plastic conver is not warped to the point that it contacts belt.


LIFE'S SHORT GO FISH


chloemiller
Novice

Feb 4, 2011, 1:38 PM

Post #8 of 17 (6896 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

pulled it all apart just now, my tensioner pulley bolt was snapped in half, my belt wasnt broken.
my upper idler pulley is now crooked and stuck in there now too.
both pulleys had busted through the timing belt cover


was it because i tightened the pulley too much??

was it because of my helicoil?

can i fix this?

can i do a cylinder leak down test without a timing belt? if so...how do i find TDC for each piston?


(This post was edited by chloemiller on Feb 4, 2011, 1:45 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Feb 4, 2011, 2:12 PM

Post #9 of 17 (6890 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

You can check it with the belt off and you don't have to worry about TDC because the crank won't be connected to the cams. With the valve cover off, just rotate either cam until both valve are completely closed. DO NO FORCE ANYTHING!. If you meet resistance, rotate the opposite direction and move the crank slightly to gain more clearance.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chloemiller
Novice

Feb 5, 2011, 8:00 AM

Post #10 of 17 (6882 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

i keep readin several times on mpvclub.com that it is a non-interference engine. so that gives me hope. my main issue is my messed up threads.

ive installed a helicoil on the upper idler pulley before, will this make it harder to fix? can i just use the same helicoil (it came with a pack of 12 of them) or will the hole be bigger?

the tensioner pulley bolt snapped off in the threads.

im just wondering if i should get a mechanic to do this, im pretty mechanically inclined, although, this is my first car so i am just learning.

im pretty sure that my theory about over tightening the bolt was right. if the tension pulley was too tight, it couldnt move freely, therefore the tension wasnt correct. and too tight. it got to a point that the belt was so tight, that it pushed the idler pulley up through the timing belt cover and the tension pulley out through the cover. im kicking myself for not spending an extra day finding a torque wrench.

i guess no one on the internet can tell me if i feel comfortable drilling out those holes or not....


re-tired
Veteran / Moderator
re-tired profile image

Feb 5, 2011, 9:58 AM

Post #11 of 17 (6876 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

Dont take this personally . You do not have a very good track record on this particular repair . You have been able to handle your own repairs up to now , but everyone has their limit. If this was a mechanic messing this up this many times you would be looking for a new mechanic .Having a pro straighten this mess out will be cheaper than a used eng for parts


LIFE'S SHORT GO FISH


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 5, 2011, 12:45 PM

Post #12 of 17 (6868 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

I don't know what people are telling you but that is an interference engine for both the SOHC and the DOHC.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chloemiller
Novice

Feb 6, 2011, 11:09 AM

Post #13 of 17 (6855 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

im getting that it IS an interference engine, and also that it is a NONinterference.

i dont know who to believe.

im trying to figure out if my valves are bent or not.
im not totally sure how to do this.

but i want to find out. and if miraculously they aren't, then ill bring it to a mechanic to fix my mess


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 6, 2011, 2:11 PM

Post #14 of 17 (6852 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

My information comes from Alldata, not some guy that is an expert because he owns a Mazda.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chloemiller
Novice

Feb 6, 2011, 2:19 PM

Post #15 of 17 (6849 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

i understand.....
theres also been "mazda techs since 1986" saying its non interference. either way, i cant just believe one or the other. i have to figure out if my valves are bent.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 6, 2011, 2:33 PM

Post #16 of 17 (6846 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

 

This chart was supplied by the manufacturer






~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Feb 6, 2011, 2:34 PM)


chloemiller
Novice

Feb 9, 2011, 10:45 AM

Post #17 of 17 (6823 views)
Re: 95 mazda mpv timing belt keeps shredding Sign In

I have deleted your post. We can't allow inaccurate statements like that.


(This post was edited by Hammer Time on Feb 9, 2011, 10:57 AM)






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