I am new here and have been reading lots of previous threads about this harmonic balancer bolt. My $700 Montero had a loose bolt and it took out the sensor plate. I have been looking at the balancer and the bolt and I wonder if it's possible to safety wire that thing! I thought I'd bring this up and see what others thought. I think one could easily drill the head and two small holes in the side of the balancer and use some .032 wire. It would be tight to get it in there but do you all think it might help? I can't see that it would hurt! I am going to try it on the old parts I took off of mine with some .020 wire I have and see how it goes. Any opinions?

Safety wire is to keep bolts from backing out or unscrewing. That is not the problem with the crank bolts we are dealing with. They like to break, wire is not going to help. Get a new updated bolt and torque it properly. That is your solution.

In my case, it actually was the bolt backing out. I think some do back out even with the newest version of the bolt because some mechanic who does not know the history does some type of front end work (timing belt, oil seal, whatever) and thinks that 130 is overkill and just get's "close". Safety wiring would have helped in my case the first time the bolt came out, but then I would have had to have been the one to wire it and therefor I would have already met the right spec.

Really that's a bit of a round about way to say I basically agree. Since all of us on here know about it, we should all check our own bolts, get the newest version, and torque it to spec. If you are really worried, then wire afterward but know it is unnecessary since my un-wired one has held for what, 60 or 70K miles so far...

Mine did the same thing! It was only loose! I had to get everything from the seal forward new and any longer running it would have needed a new crank I think. I will tourqe it to spec and it will be new but I don't want to take the chance of it happening again. I will say the bolt I took out was the new design but some slug used a standard "hardware store" washer and I believe that had some bearing on my problem.
After reading all the threads I have on this one simple bolt I have never heard anyone come back and say that their new design bolt has several thousand miles of trouble free use! That is good news!

70K on my new bolt, That means its time to do the timming belt again, dang it.

I'm fairly certain that nobody has had a harmonic balancer problem when they have an updated bolt that's been torqued correctly. Keep in mind that drilling the bolt head for safety wire is only going to weaken it structurally and add stress points from which cracks can develop. If you're that concerned about it coming loose, use threadlocker and torque it properly.

Personally, I'm convinced that 99% of the problem is caused by the bolt not being torqued correctly. This problem is not exclusive to Mitsubishi engines - Toyotas and Mazdas have similar problems - but the engines that have the problems all have timing belts that have to be changed. With an average mechanic possessing questionable abilities or knowledge to do a timing belt job correctly when it requires extra effort to make sure the torque is correct, it's no surprise that they fail.

I may do it as a precaution...and I may not. It is good to hear that several people have not had an issue after using a new bolt! You know how it is, you only hear about the problems not the things that are going good! I have the new parts just waiting for the time to do it.

As I mentioned earlier mine had a new bolt and had loosened off. I think it was due to the cheap washer they used; it was just an average washer you get at a hardware store and the factory washer I have now is close to 3/8" thick.

I'm really not complaining much as the guy I bought it from thought it would need a new engine because he was sure it jumped time when in reality it was the bolt had come loose and allowed the two pins holding the sensor plate to shear, or were beaten to pieces, giving the plate the ability to move and that made the ignition "timing" off. I got lucky this time...I usually don't! <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

See my comment above about competent mechanics. If they weren't even conscientious enough to get the correct washer back on there, what makes you think they took the time to prevent the engine from turning and torque the bolt properly?

The washer is a special belleville washer, domed outward so it provides some spring loading on the harmonic balancer. A flat washer will not provide this "springiness", and so the bolt has a greater tendency to back out under the vibrations that the crank and bolt and harmonic balancer experience. The harmonic vibrations are transmitted down the crank to the balancer, which damps them, both thru the crank and the bolt, and this tends to make to bolt "walk" out of the threads. The belleville washer will absorb some the vibrations, lessening the effect on the bolt. I think yours backed our solely because of the wrong washer. I've seen some that I suspect had a bolt failure and some wallowing out of the balancer bore, and then were put back together without replacing the balancer, and the wobbling balancer caused a subsequent bolt breakage from the bending due to balancer wobble.

I would not wire the bolt, I'd just use a small dab of red threadlocker and the right washer.

I agree with the competent mechanic comment! I can say I have never had to take my cars to anyone to have work done other than machine work! I just don't trust them so I'll just figure it out! I've worked on Mercedes' to old VW bugs!

I want to look closer at the new washer I have. It didn't appear to be a Belleville type but it makes sense! I had planned on lock-tite!

I appreciate all the discussion on this! I can always learn something new!