Comasco Posted February 28, 2008 Share Posted February 28, 2008 I bought a 92 pathy 4x4 yesterday and the guy i bought it from is the original owner. He stated he has never replaced the timing belt or any other major componant of the engine. It has 250,000 miles on it. I've never done anything more than bolton parts and tuneups. The repairshop wants $700 for timing belt/waterpump replacement. Is it bad to wait a couple months before replacing the timing belt? Link to comment Share on other sites More sharing options...
adamzan Posted February 28, 2008 Share Posted February 28, 2008 Uh, I'd do it ASAP, it's due every 105k miles. I'm at 140 and I'll be changing mine in the next day or two. You could wait, but as it's been ed into me many many times, its a ticking timebomb. If it goes, you pretty much need a new engine. Link to comment Share on other sites More sharing options...
GhostPath Posted February 28, 2008 Share Posted February 28, 2008 92 timing belts are due every ****60K**** not 105K. Link to comment Share on other sites More sharing options...
adamzan Posted February 28, 2008 Share Posted February 28, 2008 (edited) 92 timing belts are due every ****60K**** not 105K. Oh sorry, i forgot that the 93+ have the round tooth belts and the 87-92 have the square. My bad. I wouldn't drive that thing too much then, I rememeber when the tbelt snapped on our 89 mazda 929 (it was an interference engine, but somehow survived) Edited February 28, 2008 by redfinder Link to comment Share on other sites More sharing options...
Casey.T Posted February 28, 2008 Share Posted February 28, 2008 its not that difficult to change... theres a write up on it in the how too... If you dont change it, and it goes... $900 just for the new motor, or 400 for new heads and you still have all the labor... labor is actually less for a motor swap then a full head job... if you want some pics of a slipped belt, i have several... Ya I did not listen to the advise either... please note JDM swap in my sig.... Link to comment Share on other sites More sharing options...
unccpathfinder Posted February 28, 2008 Share Posted February 28, 2008 wowzers...thats a lotta miles on 1 belt...its not fun if you snap it...when I did it in my 87 at like 125k I ate 3 valves...this weekend I'm doing a frontier that just drove cross country with 125k on it towing a trailer and with the whole family...glad his luck is better than mine... and yes the VG is an interference motor unlike most of your domestic engines...what this means is the valve is in the cylinder during an exhaust or intake stroke...if the timing belt breaks the timing between the valves and pistions is off and causes the minimal damage of bending a valve from the piston hitting it...the damage can get much worse from there... Link to comment Share on other sites More sharing options...
adamzan Posted February 28, 2008 Share Posted February 28, 2008 (edited) and yes the VG is an interference motor unlike most of your domestic engines... And thats also why the japanese imports can squeeze more power in a smaller package. Or so I've heard. I can't belive it but the guy at one of the nissan dealers here told me that only the 60k belts were ones you had to worry about and the 105k ones typically would last the life of the truck. Will never be going back there again. Edited February 28, 2008 by redfinder Link to comment Share on other sites More sharing options...
Comasco Posted February 28, 2008 Author Share Posted February 28, 2008 (edited) I'm gonna have to see if i can scrape together 700$ because i've read the writeups and i know i would screw it up. Also most of my tools were stolen. Edited February 28, 2008 by Comasco Link to comment Share on other sites More sharing options...
unccpathfinder Posted February 28, 2008 Share Posted February 28, 2008 its not that bad...its just a matter of being careful and paying attention to details...I've done quite a few and have yet to screw one up and my 1st exposure to anything major was when I did my WP (neglected to change the belt) then after the belt broke I got to learn the internal work too which sucked but gave me that confidence on doing more things... The only specialty tool you need is a "crows foot" style harmonic balancer puller the rest is basic sockets and screwdrivers Link to comment Share on other sites More sharing options...
mws Posted February 29, 2008 Share Posted February 29, 2008 I can't belive it but the guy at one of the nissan dealers here told me that only the 60k belts were ones you had to worry about and the 105k ones typically would last the life of the truck. Will never be going back there again. In a rather perverse way, what he's saying is true.... A round tooth belt is not going to spontaneously expire at 106,000 miles. All belts degrade at a linear rate. In other words, every time they go flex, they get a tiny, tiny bit weaker. And so they get a tiny, tiny bit more likely to fail. So at 106K, it is only a little bit more likely to fail than at 105K. The recommendation to change is based on some kind of "acceptable failure rate". I don't know what it is. But for sake of discussion, let me MAKE UP some numbers. I am pulling these completely out of my arse - I have no idea what numbers Nissan's engineers were given to work with. Let's "GUESS" 1%. If Nissan's warranty claims/marketing department says they only want to see 1% of vehicles ever fail in the field, the engineers figure out at what mileage the belt has a 1% chance of failure - and set that as the recommended mileage. At 150K, it may be 10% chance. At 200K, maybe 40%. At 250K, maybe 75% chance. Again, these numbers are ALL MADE UP!!!! But I believe the % risk of failure will go up at a exponential rate with miles. So... if you're a gambler, you can definitely leave the belt alone. Using my made up numbers, you've got a 25% chance of it working fine at 250K miles! Back to my original statement that in a way, the belt "will last the life of the truck". If you are one of those people that believe vehicles can't/won't/shouldn't be kept for over 150K miles, there is an extremely high chance it will last that long with the original belt. So why bother to replace it? Another scenario where that statement appears to make sense: If it did break at 145K, and the cost to rebuild the engine is $4500 and you feel the vehicle is only worth $4,000, then gosh, I guess it has reached the end of its life! (Yes, that is flawed logic, but people behave that way every day!) But if you're one of us whackjobs that drive vehicles for well over 200K, then it gets very important to change. Link to comment Share on other sites More sharing options...
adamzan Posted February 29, 2008 Share Posted February 29, 2008 (edited) Wow you really know what you're talking about, you must be an engineer I say that as my dads friend is a mechanical engineer and everytime I see him we somehow get talking about my and my dads pathfinders. He said the same thing that you did about the belt today, that its not going to break exactly 1000 miles over. For example in my 93 my dad said he never replaced the timing belt and the truck has 340,000 kilometers, and never had a problem. Edited February 29, 2008 by redfinder Link to comment Share on other sites More sharing options...
mws Posted February 29, 2008 Share Posted February 29, 2008 Dohhhh! Guilty as charged. Mechanical Engineer, Physics minor. 18 years in industry playing in design, reliability, quality, sales... Please don't hold it against me... Link to comment Share on other sites More sharing options...
Casey.T Posted February 29, 2008 Share Posted February 29, 2008 And if you want to know what the insides look like after it goes... Ask Martin he has my blown motor.... in pieces... Link to comment Share on other sites More sharing options...
adamzan Posted February 29, 2008 Share Posted February 29, 2008 And if you want to know what the insides look like after it goes... Ask Martin he has my blown motor.... in pieces... I'd like to see pics of what the belt looked like when it failed. Link to comment Share on other sites More sharing options...
Casey.T Posted February 29, 2008 Share Posted February 29, 2008 There was about 15" of missing teeth... Link to comment Share on other sites More sharing options...
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