Gen 3 crankshaft pulley bolt!

Epyx1977

New member
So today I learned all about the crankshaft pulley bolt. Specifically the problem of the bolt backing out.

My 06 3rd gen has 119k miles. Noticed the problem after the serpentine belt started slipping and I replaced it with a new one. Problem didn’t go away so I then figured the tensioner pulley must have gone bad. I pulled the belt off to diagnose the pulley and notices that the crankshaft pulley had a ton of slack and play. Seemed odd so I started googling and found out about this being a problem area. The good news (maybe) is that the bolt is not broken as far as I can tell. It is still holding somewhat.

I confirmed that the bolt that I have is the old problem style and not the revised version. I had the timing belt done recently and I am surprised they didn’t replace it then.

Anyway - can’t drive it like this so would like to fix this myself. Anything I should be aware of from anyone who has done this repair?


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Salonika

Monterror Pilot
Ok.....stop the bus. To my knowledge, the crank pulley bolt problem shouldn’t have carried over in the Gen-3’s. It was a manufacturing defect that I thought was resolved by Mitsu within the Gen 2 to 2.5 time period.
 

Epyx1977

New member
Ok.....stop the bus. To my knowledge, the crank pulley bolt problem shouldn’t have carried over in the Gen-3’s. It was a manufacturing defect that I thought was resolved by Mitsu within the Gen 2 to 2.5 time period.
I don’t know either way but mine backed out for sure. Maybe it was not torqued correctly?

The crankshaft pulley (harmonic balancer?) is still attached but not tight against the engine and thus wobbles.

I removed the belt and can reach down and move the pulley back and forth (not around) with my hand.

I plan to remove the bolt to inspect condition of it and the pulley.

I can replace the bolt and washer but wondering if I can re-use the existing bolt as a temp repair.

I want to limp it to a garage to do the repair and inspect to make sure nothing else more significant got damaged that I can not see or would not be aware to check.


This picture probably helps 0% but you can kinda see the pulley is not in alignment with the others.

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RyanY

Adventurer
The bolt coming loose is not a problem with the bolt itself, it's a problem with the last person to service the timing belt and their failing to torque it properly (it's not a problem specific to Mitsu V6s, there are plenty of other engine with timing belts that have similar issues). The inherent problem with the bolt is a breakage issue, and if you don't have the most recent design it needs to be changed (a quick search should show what the newest version looks like). Most shops have no idea about the upgraded bolt being necessary and wouldn't replace it unless the owner informed them of it.
 
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plh

Explorer
In reality, the bolt should be changed to a new one with each timing belt service, or any other time the bolt is removed/replaced. And as RyanY mentioned, use a torque wrench to spec. IIRC the Gen 3 spec is updated (higher) from what the FSM says as well.
 

Epyx1977

New member
In reality, the bolt should be changed to a new one with each timing belt service, or any other time the bolt is removed/replaced. And as RyanY mentioned, use a torque wrench to spec. IIRC the Gen 3 spec is updated (higher) from what the FSM says as well.
Ok - so got lucky and the only “damage” appears to be the to the pulley. The metal on the inner portion is chewed up from wobbling. The lower timing belt cover and the idler pulley (or whatever is back there) looks ok.

I will replace all the parts but to check and make sure nothing broke internally (forgive me if that sounds stupid) I put everything back together with the existing parts to see if everything ran smoothly. I also added some lock tight to be safe. Engine seems to run smooth a quiet. No lights. I don’t plan to drive it any further than the mechanic down the street and not until after the new parts arrive.

I ordered a new bolt, washer, and pulley. Anything else I should replace? The belt is new.


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Swift_45a

Observer
Why not just replace the belt. Maybe the wobbling did something to it to make it off just a bit
Second that.

I'm now 1/2 into what I thought was just a harmonic balancer issue on my 2.5 and I'm having to replace all of the parts attached to the crank, turns out the wobble did way more damage than I thought despite it running and driving.

I'll be updating the HB thread later today with pics and such once I can get this thing on time (I'm off by a fraction of a tooth on the new crank timing sprocket and its causing a sputter) as I'm aving issues with the tensioner on the Right cam throwing it off.

But the timing belt was all chewed up on the exposed side to the timing cover.
 

RyanY

Adventurer
I'll be updating the HB thread later today with pics and such once I can get this thing on time (I'm off by a fraction of a tooth on the new crank timing sprocket and its causing a sputter) as I'm aving issues with the tensioner on the Right cam throwing it off.
Your sputter is not being caused by the cam timing being a fraction of a tooth off, you've got another issue somewhere. Over the course of it's service life the timing belt will stretch slightly, and it will end up being off by at least that much before it is changed. If being off by that small amount caused driveability issues there would be no Monteros running with more than 20K miles on the timing belt.
 

Swift_45a

Observer
Your sputter is not being caused by the cam timing being a fraction of a tooth off, you've got another issue somewhere. Over the course of it's service life the timing belt will stretch slightly, and it will end up being off by at least that much before it is changed. If being off by that small amount caused driveability issues there would be no Monteros running with more than 20K miles on the timing belt.
Its a brand new timing belt, sprocket, spacer, woodruff key and it ran fine prior to disassembly, which looking at how damaged the sprocket/spacer and woodruff key (look at my post) still is a shock to me.

Its that I cannot get the right position on the Hydrolic tensioner without knocking it off timing on the crankshaft, the cams are on but the crankshift sprocket moves on the 2nd rotation.

I can hear it fire up fine on the first Revolution on the crankshaft, but the 2nd when it fires with the cams on time is not and causes the stutter. Its a technique thing I cannot get as I end up in the same position everytime. I can post video on the other thread, seeing as how I had to focus and catch up school work and apply to other jobs until I get a call back from a mobile mechanic to try and sort it out.
 

Michael Brown

You followed me, so now we're both lost
Ok.....stop the bus. To my knowledge, the crank pulley bolt problem shouldn’t have carried over in the Gen-3’s. It was a manufacturing defect that I thought was resolved by Mitsu within the Gen 2 to 2.5 time period.
My 2005 Gen 3 with 3.8l definitely had the long crank bolt installed from the factory. I changed it to the short one a few years ago. Installed a new one again after changing timing belt, but saved the old ones anyway.

Torque is pretty high in the FSM, but I added a little blue loctite to be on the safe side.

Slightly Off Topic:
Also, I have now discovered Permatex Orange Threadlocker. Higher release torque than blue, almost as high as red, but nor heating requirement for removal. Just hand tools to take it off. I would have used this on the crank if I had known about it.
I used this on the manifold butterfly valve screws last week and will update if anything happens to them.
 

Epyx1977

New member
Ok so the problems are worse than I thought.

Threads are ok. New bolt goes in no problem. However that crankshaft gear looks like garbage as does the lower timing cover.

I plan to replace the crankshaft gear (md184894) and the timing cover (MD366568). I already have the new bolt, washer and harmonic balancer.

Anything else I should order? The timing belt looks unscathed and it literally has less than 1k miles on it.

I see kits available for the sport but not the same for the full size 3.8.


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Michael Brown

You followed me, so now we're both lost
RockAuto sells kits by Aisin and some other manufacturers if you need one. Might want a crank sensor depending on whether it was damaged.
 

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Epyx1977

New member
Ahhhhh I should have tried Rock Auto. I bought a kit from Amazon and I am a little worried about part quality given it’s not OEM or even a brand I am familiar with. Reviews are positive but I don’t trust the Amazon review system. Hopefully the kit looks good when it arrives tomorrow.

I had more difficulty finding the lower timing cover but did find an OEM one at Mitsubishi Parts Warehouse. Cheaper parts all things considered. Labor is going to be a bear.

This is the set I picked up:
Koauto Crank Crankshaft Gear Sensors Blade And Spacer Kit For Mitsubishi Montero https://www.amazon.com/dp/B07DJDRYB6/ref=cm_sw_r_sms_api_i_jWAiFbNHXP4AD

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Michael Brown

You followed me, so now we're both lost
Another source for OEM parts is PartSouq. The are our of UAE, but ship pretty quickly. I think they are a central hub for global parts distribution.
 
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