3.8L timing belt change (gen 3)
- Thread starter The Viper
- Start date
2to4wheels
Adventurer
This is a very useful thread. This weekend my brother and I are going to be tackling this job on my new to me 06. I've decided to go with the AISIN kit which based on what I've read, I should be pretty comfortable with.
Other than the parts included, is there anything else I should tackle with this job other than the cam seals? I've seen this thread here that also talks about spark plugs, valve cover gaskets etc...
http://www.expeditionportal.com/forum/archive/index.php/t-152283.html
And finally, not sure I understand what I need to be looking for with the crank bolt design. Can someone enlighten me?
Thanks
Other than the parts included, is there anything else I should tackle with this job other than the cam seals? I've seen this thread here that also talks about spark plugs, valve cover gaskets etc...
http://www.expeditionportal.com/forum/archive/index.php/t-152283.html
And finally, not sure I understand what I need to be looking for with the crank bolt design. Can someone enlighten me?
Thanks
Last edited:
plh
Explorer
Just out of curiosity - how many people actually had to replace bent valves due to failed tensioner on the these engines? I always hear that all hell will break loose but never heard of it actually happening
Guessing this is one:
http://milwaukee.craigslist.org/cto/5699457676.html
I finally got around to changing the timing belt and componets, and we are really struggling trying to get the the right tension on the belt with the tension pully. We started using a generic version of the mitsubishi tool that fits in the 2 holes but that broke, then we tried using the ends of pliers but that isnt working well either, they keep slipping out of the holes. At one point we did get it tensioned right, where the pin to the hydraulic tensioner could slide in and out easy, but after 5 minutes the protrusion of the piston was 2 low/short.
So the 2 holes on the pulley tensioner line up with the hydraulic tensioner when the tension is correct? I thought i read that somewhere.
Is it just me or does it take a ton of force to move those 2 holes in correct tension?
Once you have the tension on the pulley via the 2 holes, then you hold that force, and tighten the center bolt to spec?
I think someone mentioned using snap ring pliers, but the pair i had were not even close to fitting
Anyone have any additional tips or suggestions?
So the 2 holes on the pulley tensioner line up with the hydraulic tensioner when the tension is correct? I thought i read that somewhere.
Is it just me or does it take a ton of force to move those 2 holes in correct tension?
Once you have the tension on the pulley via the 2 holes, then you hold that force, and tighten the center bolt to spec?
I think someone mentioned using snap ring pliers, but the pair i had were not even close to fitting
Anyone have any additional tips or suggestions?
cacattack
Observer
I don't recall ever looking to see if the holes aligned with the tensioner, if i recall correctly the holes will basically site level or very near level. Not sure if that is correct.
The tension is not all that great. Make sure that you are measuring in inch lbs and NOT ft. Lbs. I believe it to be 39 inch lbs. I would recommend this tool, as this is what I used connected to an torque wrench to get the accurate tension measurement.
https://goo.gl/images/tqPqvO
Yes hold tension at 39 inch lbs while tightening pulley to 35 ft. Lbs. It will require two torque wrenches to get it accurate.
Craig
The tension is not all that great. Make sure that you are measuring in inch lbs and NOT ft. Lbs. I believe it to be 39 inch lbs. I would recommend this tool, as this is what I used connected to an torque wrench to get the accurate tension measurement.
https://goo.gl/images/tqPqvO
Yes hold tension at 39 inch lbs while tightening pulley to 35 ft. Lbs. It will require two torque wrenches to get it accurate.
Craig
Tundraguy81
Observer
My tensioner went bad and threw the timing off enough to throw crankshaft and camshaft position sensor codes and my Montero cut off while driving. Luckily no damage was done.
I think the issue is we got fixated on getting the 2 holes parellel with the hydraulic tensioner and trying to add way too much force to get it parrellel, which wasnt happening because when we installed the the tensioner pulley holes slightly at an angle. I think we will take out the tensioner pulley out and put it back with the 2 holes almost in a nice line with the hydraulic tensioner, that way when we add that 39 inch pounds the holes should line up with the hydraulic tensioner.
I just bought a nice pair of snap ring pliers, which look like its gonna work real well.
The other thing to note, is when we did get it tensioned one time, and the pin could slide in and out easy, we pulled the pin, let it sit for 5 minutes, and then check the portrusion of the piston, and it measured 4.6mm (suppose to be 4.8-5.5mm). I wonder if 4.6mm was close enough? Also when we pulled the pin out we forgot to turn the crank around a couple of time and maybe thats why it was measuring 2 low.
I just bought a nice pair of snap ring pliers, which look like its gonna work real well.
The other thing to note, is when we did get it tensioned one time, and the pin could slide in and out easy, we pulled the pin, let it sit for 5 minutes, and then check the portrusion of the piston, and it measured 4.6mm (suppose to be 4.8-5.5mm). I wonder if 4.6mm was close enough? Also when we pulled the pin out we forgot to turn the crank around a couple of time and maybe thats why it was measuring 2 low.
PA_JERO
Adventurer
When you set the tension, the pin should be able to slide in and out after torquing the tensioner pulley bolt. Then pull the pin and rotate 2 or 3, or more if you feel that's necessary. Then like you said, let it sit for 5 minutes, then the pin should be able to slide in and out again. The 39ft-lbs is about what the torque should equate to. I've used a torque wrench before on the special tensioner tool, but that doesn't always work out very well, especially when trying to torque the bolt down as well. The holes on the pulley do not need to be lined up with anything. As long as you have good tension on the pulley/belt, that pin will slide in and out easily before you rotate, and after you rotate.
Well we finally got the tension correct on the tensioner pully and our protrusion on the hydraulic piston was 4.9mm after turning the crank around 2x and letting it sit for 5 minutes ish. I think the part of the problem was, initially, i was using a 14mm wrench on the tensioner pulley center bolt and it felt like i was putting a ton of force into tightening it, but in reality it wasnt tight enough. Once we put the torque wrench on it right away while my buddy held the tension on the pulley, we finally got the center bolt tightened to spec.
The timing marks all look good, but man, the crank pulley timing mark really messes with you, it will look off when your looking at it from the top. We kept saying to each other..."is it off by a little or is it on" I read from a mitsu tech, that if your off by one tooth it will look way off, and if it looks a little off your prolly good to go.
We are buttoning it up now, ill have some more information/tips to share for people looking back on this thread to do there timing belt when everything checks out good
Thanks for all the help and suggestions!
The timing marks all look good, but man, the crank pulley timing mark really messes with you, it will look off when your looking at it from the top. We kept saying to each other..."is it off by a little or is it on" I read from a mitsu tech, that if your off by one tooth it will look way off, and if it looks a little off your prolly good to go.
We are buttoning it up now, ill have some more information/tips to share for people looking back on this thread to do there timing belt when everything checks out good
Thanks for all the help and suggestions!
Got everything installed back smoothly, everything started up perfectly.
The only issue i appear to have...the AC isnt working, on the rv meter display there is a blinking snowflake symbol when i turn the blower on
could we have forgotten to plug something in on the ac compressor?
The only issue i appear to have...the AC isnt working, on the rv meter display there is a blinking snowflake symbol when i turn the blower on
could we have forgotten to plug something in on the ac compressor?
Tundraguy81
Observer
It's possible. The plug for the AC is on the driver's side valve cover near the front of the engine.
That was it, thanks
Had some trouble finding one end of the connector, it was buried beneath the power steering pump. The one one end has a bracket on it, I'm not sure where it attaches to. If someone could post a pic, that would be helpful
So just some final thoughts/tips on this timing belt change
1)For a DIYr non mechanic im really glad i had a buddy helping me with this, i dont see how i couldve managed my 1st timing belt change without a 2nd mechanically inclined person.
2)I wish i wouldve splurged and bought an Aisin kit...it includes everything OEM in the kit. The peace of mind wouldve been worth the xtra cost considering all the time that went into this job. I originally bought a Dayco timing belt kit, but i did upgrade to a mitsubishi OEM hydraulic tensioner and a Gates timing belt. The Dayco kit included a front portion GMB water pump and GMB tensioner. The old Aisin waterpump had metal gaskets seemed much more hardcore then the GMB gaskets
3) Changing the CAM seals was a must and im glad i went ahead and had bought the OEM cam seals from Mitsu. The Passenger cam seal was leaking pretty good. However changing these seals was a real pain. The seal puller i bought (linked in this thread) was junk and ended up breaking while trying to remove the seal. My buddy ended up making something that eventually worked.
4) the passenger cam is an absolute bear. It balances right on the timing mark, move it a little to the left or right and gets way off fast. I caught my buddy using a ratchet on the 17mm cam bolt, and i about had a heart attack. I quickly let him know you must use a wrench and two hands so it doesnt get away from you.
5) using binder clips on the cam to hold the timing belt worked great, and i cant imaging not using something to hold the belt on at the cams.
6) the pulley holding tool was fantastic (linked in this thread), and the crank bolt came right off without much difficulty. I did have the old dumbbell design crank bolt so im glad i had ordered the updated design from Mitsu.
7) the tensioner pulley was a real pain. I bought the actual generic mitsu tool but it broke. This is where an xtra set of hands is really helpful, one person can set the tension and check the pin while the other can tighten down the center bolt with a torque wrench
8)having the FSM printed up was an absolute must. Having the torque specs and bolt sizes helps everything get put back smoothly.
9) the fan clutch bolts, what a nightmare...they were torqued on way too tight. We ended up rounding one of the nuts and that took hours to get off. Be really careful with those.
Im sure there are other things to mention, ill edit this post if i think of more
Thanks to all the help in this thread!
1)For a DIYr non mechanic im really glad i had a buddy helping me with this, i dont see how i couldve managed my 1st timing belt change without a 2nd mechanically inclined person.
2)I wish i wouldve splurged and bought an Aisin kit...it includes everything OEM in the kit. The peace of mind wouldve been worth the xtra cost considering all the time that went into this job. I originally bought a Dayco timing belt kit, but i did upgrade to a mitsubishi OEM hydraulic tensioner and a Gates timing belt. The Dayco kit included a front portion GMB water pump and GMB tensioner. The old Aisin waterpump had metal gaskets seemed much more hardcore then the GMB gaskets
3) Changing the CAM seals was a must and im glad i went ahead and had bought the OEM cam seals from Mitsu. The Passenger cam seal was leaking pretty good. However changing these seals was a real pain. The seal puller i bought (linked in this thread) was junk and ended up breaking while trying to remove the seal. My buddy ended up making something that eventually worked.
4) the passenger cam is an absolute bear. It balances right on the timing mark, move it a little to the left or right and gets way off fast. I caught my buddy using a ratchet on the 17mm cam bolt, and i about had a heart attack. I quickly let him know you must use a wrench and two hands so it doesnt get away from you.
5) using binder clips on the cam to hold the timing belt worked great, and i cant imaging not using something to hold the belt on at the cams.
6) the pulley holding tool was fantastic (linked in this thread), and the crank bolt came right off without much difficulty. I did have the old dumbbell design crank bolt so im glad i had ordered the updated design from Mitsu.
7) the tensioner pulley was a real pain. I bought the actual generic mitsu tool but it broke. This is where an xtra set of hands is really helpful, one person can set the tension and check the pin while the other can tighten down the center bolt with a torque wrench
8)having the FSM printed up was an absolute must. Having the torque specs and bolt sizes helps everything get put back smoothly.
9) the fan clutch bolts, what a nightmare...they were torqued on way too tight. We ended up rounding one of the nuts and that took hours to get off. Be really careful with those.
Im sure there are other things to mention, ill edit this post if i think of more
Thanks to all the help in this thread!