Gen 3 Timing Belt

[Steve-O]

Greetings,

My 16 y/o Son just sold our pretty clean Gen 1 and I just picked (him) up a 2003 Montero limited several months back and its been one thing after another just trying to get it Check Engine Light free so we can attempt to move from non-op status to registered and drivable. My code reader listed more codes than you can shake a stick at. After pick ur part visit (Mass airflow and airbox) and fiddling around under the hood on and off, finally got down to last code (P0174 Lean bank two). Homemade smoke test revealed the infamous vacuum leak at front plastic bushing in lower intake plenum. So, I read up here and on other forums and contemplated the new $627 oem part (online purchase) vs. trying to fit new o-ring to seal up vacuum leak while at the same time planning to do something with the "piston eating screws" i keep reading about (was hoping to loc-tight and stake if at all possible). Then I began to get up the courage to attempt to tackle this intake plenum repair (at 50, haven't done much more than light maintenance last 25 years as we have household of newer vehicles) as I am a bit out of the wrenching game since my college days of pulling vw engines in 10 minutes, but figured with the FSM and forum, we can get it done and utilize the old tools that have been sitting around collecting dust.

Well, you are likely wondering how the title of the post "Timing Belt" fits into this? Few days back we were in garage and I happened to spot a puddle under the Gen 3. Slid under to find waterpump has a nice drip. The nice chap we bought the vehicle from explained that the guy he purchased from two years plus earlier had done the whole T belt/Waterpump service approx 12-15K miles previous. But, for the peace of mind, I figure rather than just trust the belt, tensioner, etc and only do the pump, I'd spend few extra bucks and do the whole thing from ground up. We plan to build up a nice overlander and would like to get out to Anza, Sierra Nevada region, or wherever else this Mitsubishi can lead us. So we need dependable!!! So now I need to get the vehicle driving again before we can refocus back on the lean bank two issue with the vacuum leak on the lower intake plenum.

So, this leads to this post (you knew I'd finally get there... ) I am a bit of a searching novice on these forums. I know this has been covered plenty of times. How do I find the best "how to" on the Timing Belt for a Gen 3? I have printed FSM and using only that scares me a bit. I logged in and entered Timing Belt in search box and got a few chaps asking about the same as I need... where to buy parts, etc? basic how to do this or that. I have read previously that some guys really took some time to help others out and put nice write up together. Any posts come to mind?

Spoke to the Mitsu guy in Van Nuys (C&A) that most of you SoCal guys speak of who advised that many of you utilize a parts distributor in Torrance, CA?? Or maybe he said it was Carson, CA??? Still trying to figure out if I can tackle this myself, or if I'll buy the parts and tow it the 60 miles to the valley and drop a substantial amount of money (for some reason Chai (spelling?) preferred I purchase the parts and just pay him for the labor)?

I will likely check into the infamous Rock Auto kit with the Aisin pump and corresponding parts unless someone here can direct to better supplier. Also need cam/crank seals, crank bolt, etc. and don't know if these are dealer only for good quality? Guessing OEM seals would be good idea... gonna limit to the T-belt and worry about valve cover gaskets and other goodies when we have more time and energy. That plenum job is lurking around the corner and has me thinking about the few additional items to do as well (plugs, injectors, butterfly valves, etc.).

So to recap... need a good how-to and a line on oem parts (other than dealer) here in Socal. I have searched online at Mitsu parts folks and this is always an option i suppose.

Any ideas or advice greatly appreciated. Also, wouldn't mind finding another 2003-2006 here in Socal area if you have a lead or two. Lots of 01's around, but the 3.8's bit harder to find. A solid blue 2006 limited would be a dream!

Thanks in advance.

Steve

 

[Michael Brown]

I believe your water leak is from the o-ring on the back of the water pump housing. It tends to get forgotten about during a timing service and eventually the o-ring on the hard pipe begins to leak.

It can be accessed by the same timing belt removal that you are planning, or you can reach it under the plenum. Both options tend to be tedious, but I had already done a timing service so I went for the plenum and put in new intake gaskets. I recommend using the 2003 FSM starting with page 11B-6 for the intake removal.

The o-ring in question is this one: https://www.amazon.com/gp/product/B008RJN2SS/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
You should see a small metal pipe running down the center of the valley below the intake manifold and injectors. The pipe goes into the back of the water pump housing, but is bolted to the block by some brackets.

Removing the plenum is not very difficult, but can be tedious. I have done it twice so far, once to realize I had o-rings for the larger pipes and again to replace the correct one. I slowly disconnect the wires and vacuum lines starting at the throttle body and working left to right. The harness can be unclipped from the mounts and folded out of the way. If any brackets or sensor are unbolted, I put the bolts back in the hole or in some marked cardboard. The throttle body does not need to be unbolted, but the EGR tube on the passenger header needs to be unbolted to remove it from the engine bay.

The 3.8L plenum has multiple bolts, but only the 7 long bolts in the middle of the plenum hold it down to the manifold. The one at the back is close to the firewall so I used a 1/4 with a universal and extension to get back to it. You can see their pattern on a plenum gasket in the diagram. The others on the right side hold the plenum together.

Once the plenum is off, you will see the fuel rails and intake manifold. You also need to remove the water outlet housing to go further. I recommend draining coolant from the spout on the bottom driver side of the radiator. If you catch in a clean container, you can re-use it. Otherwise just refill with new fluid.

This is also where you can access the spark plugs and valve covers. Unbolt the fuel rails and carefully lift each fuel injector out of its hole in the manifold. I wrapped each one in a shop towel to protect the tip from dirt. Then you can remove the intake manifold.

You should now see the smaller diameter pipe in the center of the valley. It would look similar to this (Note: I think this is a 3.5L or older engine. I just wanted you to have a pic)


Remove the bolts at the back of the block on each side, and get it out of the back of the pump housing. Replace the o-ring and re-insert. It takes considerable force to get it back in with a new o-ring so make sure it is at least wet with water or coolant before putting it in.

This method just keeps you from going through the timing system to get to it.

As for a note on the timing parts kits, I used the $100ish one from Dayco at 105k and it is now getting replaced at 170k with the Aisin kit. I used cheap parts first because I wasn't sure if I was keeping this one.
You mentioned a leak at the plenum switch shaft. You should be able to install a new shaft o-ring while the plenum is out or remove the shaft and cap the opening with a thin piece of aluminum trimmed to fit with silicone. Might even be able to just add silicone to the leaking spot. Mine has not had this code yet so I don't have much more info.

 

[ChrisCosta416]

Hi there,

I have created a Gen3 3.8L service guide that should have all required parts to service the Gen3 when doing your water pump/TB service.

the guide has part numbers but does not have links on where to buy it. I recommend buying from rockauto and partsouq and only using the brands listed in the guide.

I’m not aware of any shop in Torrance or Carson. As for Chai, he would like you to bring the parts, then he will charge you for labor. I am pretty sure his shop is still packed right now

 

[kalieracer]

Get the Aisin kit from Rock Auto, OEM seals and tensioner and serpentine belt and bring it to Chai. The parts distro in Carson does not have a ready made timing kit for the 03-06 trucks and there are no aftermarket tensioners from an OE mfg for these trucks. they did make a OES/OEM kit for 97-00 trucks at my request. There is spreadsheet that Jamie and I made for everyone. There is no good way to fix the bushing leak, the correct way would be to make new bushings and then line hone them for the shaft, given the amount of work required to do so, it is a wash in terms of getting the correct new part that should last another 15-20 years. I have been sending customers to Chai for over 20 years.

 

[kalieracer]

AISIN is sub brand of Toyota and one of their top suppliers. They are the OEM for the WP to begin with. The kit includes the bearings from Koyo, who is also the oem for these parts for Mitsu too.

 

[Salonika]

Take pics as you go. As you remove stuff, lay it out on a table L to R or R to L or whatever as you go so when you reassemble everything is in the order you removed it. Label stuff. If you do it this way it’s way easier and almost fun.

 

[Steve-O]

Good evening,

Thank you to all of you for the thoughtful replies. All good info. Still dreaming of doing the T Belt myself, but will likely just bite the bullet and pay to have it done. My kid really wants to motor his new Montero around ... Getting the teeth off a bit and destroying some valves just does not sound like fun.

Kalieracer... can I get the name of the parts house in Carson? I'll check them out on an individual parts basis versus the rockauto kit.

Thanks again,

S.

 

[Steve-O]

Hi guys,

So I'm putting together the parts in prep for this Timing Belt / Water pump job (2003 Montero Limited with 3.8). My 16 y/o located the Mits parts reseller in Carson, CA (leave it to a tech kid). They have a very simple website under "Autocom Inc." Go to contact page and at bottom of page see the link "click here to check out our ebay store." Then directs to CB Haus. My son has mentioned some here utilizing CB Haus. Wish I had discovered CB Haus on ebay before purchasing the Aisin kit from Rock Auto as they have about same Aisin kit for bit better pricing and it includes the drive belt (tax, shipping, etc). No biggie. This was my first order from Rock Auto and they did well. In addition to the Aisin TKM005 Kit, I included Aisin thermostat, Timken seals and a bunch of other things I'll need later trying to maximize my $7.99 shipping. Couldn't bring myself to $12-16 oem seals. Hopefully I dont regret later!

Then on to locating the tensioner and crank bolt/washer. Trying to stay oem when possible. Ordered from the sand box distributor (PartSouq) in Dubai (to me this is amazing) and went off without a hitch. Pricing was great and got here in days for minimal shipping costs (maybe $11). Came from other side of world and was still cheaper than anyone else online in the US. Not sure who here wants to take credit for locating "PartSouq," but this was amazing Mitsubishi parts find.

So now trying to decide if I'm really going to pay the approx $100 for the crank sensor. My question is: anyone here had real world experience with the sensor going bad, or are the majority just changing out because its a pain and you already have it exposed when doing timing belt?? I'm sure the answer will be resounding "yes." Just trying to be as conservative with money as possible. Any here have story of sensor lasting great amount of time? I just changed out an original B/O sensor and two replacements on my water heater. It about drove me crazy trying to figure out what was causing problems with the old thing, only to find out that the crummy new sensors I were putting in were bad from the beginning. I know bad analogy, but I'm wondering if the original sensors can ever really be replaced with anything as good? I'd love thoughts here... Keeping quality, can't remember where I saw it (but likely Rock Auto?), but some aftermarket company stated they had perfected the bugs out of the crank sensor. Any other brands besides OEM worth looking at if we do decide to change out the sensor during the job ( I see a NTK option listed on a page my kid showed me)?

ChrisCosta - i searched your entire thread page and was hoping to find a write up of the actual job. I did locate the spreadsheet with part numbers titled "Service Guide." This spreadsheet is awesome! Thank you for your time if you put this together. Still looking for any tips/best practices if you know of write up?

I know I found a timing belt write up somewhere in last several weeks. Searching these forums still not my specialty.

I'm still dreaming of doing this myself, but snapping off the crank belt and installing the cam/crank seals scares me a bit. Especially the bolt! After we have all parts, I'll do do few more online video searches and make decision. Whole idea was to introduce my son to working on cars (besides the minor stuff we've done), but now he's bagging groceries at the local store and works full days Sats/Suns so I guess I'd be without an assistant. Gotta make final decision here.

Thanks to all,

S.

 

[plh]

I've done the timing belt 3 times on my '05 (yes I've owned it that long) and have not replaced the crank sensor. YMMV

 

[Steve-O]

$400 dollars for labor and whatever I paid the three sources total for the parts (Rockauto, Partsouq, and Ebay), and the kid is driving his Montero for the first time. Thanks to all for the advice.

My son really wanted to tow the thing 60 miles north to C&A. More money for labor and major pain with SoCal traffic. Went to our long-time small family owned shop here in Orange County. Not Montero specialist, but been in business too many years to count and sure they've changed their share of Japanese timing belts and water pumps. Best part is when he fired up the Montero, it didn't show any codes (i guess the week with a disconnected battery was enough). He ran it across the street to a emissions shop and got it smogged for us. Code came right back as I expected, but at least we can test drive the thing now without a worry of the non-op getting us in a bind, and have a bit more time to consider our approach to the lower intake plenum vacuum leak I discovered. New post to come for that.