Saturday, October 20, 2012

How to replace Timing Belt,Water pump And Valve Guides on Mitsubishi Montero

Vehicle details

Make: Mitsubishi
Model: Montero Sport LS
Year: 2000
Engine: 3.0

The complete details regarding replacement of timing belt,water pump and valve guides.

Its a technical and professional job.Should have all required tools to complete the task.

the Procedure as well as details to perform these task is as follows:----

For valve guide seals, you do not need to remove the cams on this model however you do have to remove the entire upper intake and valve covers of course.

I will provide you complete step by step manual to perform these task,that will make assembly dis-assembly very easy.

For you help i am providing you with the PDF of the engine repair section of the Factory Service Manual below:
The link is provided below for the PDF
6G7x Engine Repair Manual

Check pages 11A-6-1 through 11A-6-6 for timing belt repair & replace task.

  • The PDF has all  alignment marks provided as well as tensioner information, etc. 
  • The accurate torque specifications are on the first page, however any missing (I believe the harmonic balancer is omitted) will be in the "Specifications" section at the beginning of the PDF.

Water pump is not that difficult,once you get into the timing belt section.The water-pump section is further down, but for the most part it is simply remove bolts, pull out water pump once you get the belt off.

More safety and additional information.
These info is not in the PDF. These are our garage repair details,which professional mechanics follow:------

  • Always before removing the belt, take the bolts out of the hydraulic tensioner only. Leave the mechanical tensioner set. Dont remove bolts from mechanical tensioner. Dont move its actual factory settings.
  • Now once the belt is off, this is the right time to spin check the mechanical tensioner to listen for noise or looseness. 
  • If there is none and you don't need to replacement, then you won't have to adjust it later since it is already properly set. 
  • Before you  loosen this bolt in the mechanical tensioner, you really need the special tool to adjust it again. If you don't have these special tool,then don't loosen the bolt,till you get the tool to readjust it.
  • Considering these rarely fail, it can save you a bundle of time doing it this way and not having to readjust it later.


In case of water pump, aftermarket pumps will only be "half" a pump.
The aftermarket pumps are very cheap compared to original branded pumps.They are half the price of factory units because you don't get the whole thing.

A basic info about water pump if you don't know much about it.
The water pump is a large chunk of aluminum that goes all the way up to the thermostat neck, etc. Beware that Aftermarket units will only give you the front half. Now reliability of some aftermarket pumps aside, there is a bigger immediate issue with this. When you remove six of the large bolts for the front half of the water pump, you are loosening the rear half of the pump from the block. This compromises the gasket back there and you will often end up with a coolant leak after installing a new half-pump.
To combat this, apart from recommending a factory pump anyway.
 Its suggested  getting the gasket that goes on the back of the pump housing, then removing the entire pump housing to install the water pump, using the new gasket between the housing and the block.
It will not take more then 15 minutes.This extra 15 minutes is worth it in the case that you did get a leak there as you would avoid having to pull the whole front end down again.
The gasket section is mentioned on page 11A-8-1, numbered "9".
For front wheel drive the image will be slight different. but the information is all the same otherwise.
Here is what your pump and gasket will look more like (that gasket is "11" in this picture):
mitsubishi waterpump

Regarding Valve seals:----

The valve seals will require the intake to be removed. This is not specifically covered in this manual
So on these case see the exact and  the appropriate RWD intake manifold dis-assembly and torque info below; the parts are numbered in order of removal:
valve seals

Once the valve seals are removed you will be able to get to your valve covers to unbolt and remove them (this takes some tricky maneuvering so don't take these task lightly).

Please Note:--- Many Auto repair techs will not mention these,but with new valve cover gaskets, you will also need new spark plug tube seals as well. If your plug wires are oil soaked on removal, you will want to replace the wire set.

NOW,details regarding inside assembly:----

Inside you  will see rocker shafts over the valves. These are held in by 12mm bolts, loosen them evenly to remove them... be prepared for the lash adjusters to drop out.Sometimes its fast to revert back, don't loose it. OR other option you can try is,We have special tools that hold them in, but you can just lift one rocker at a time and loop some masking tape around it to temporarily hold them.

THE shaft can cause OIL flow issues:----
So its advisable,Do NOT mix up the shafts. They can go back together backwards and this will block oil flow, so make sure you note the side and orientation of each.
engine system disassembly

NOW,understanding the basics.

Please NOTE:----- The manual will not provide steps for on-car stem seal replacement as this isn't an approved repair method.

Actually there is no need as well as no sense in removing the heads for seal replacement though.

The easy and best procedure is ,Hook up your air line to one cylinder at a time and release the valve retainers one at a time.
Garage repair techs use a chrome socket with a small magnet in it to put over the stem then pop it with a rubber mallet. Its best procedure,this will quickly compress the spring and release the keepers and hopefully catch them in the magnet then you can remove the spring and perch.Keep them in safe place,it is required while reassembly.
To remove old seals I like to use an old pair of spark plug wire pliers. They usually grip them just about right then pull and twist to remove.Its very simple.
To install the new seal, slide it over the stem then use a 10mm 1/4 inch drive six point deep well socket to slide over the stem and top of the seal then tap into place. It will snap on when it seats.
Now its time to re-install the spring and perch, then use an automatic keeper tool to set the keepers back in.

The required tools to complete these task, will be easily available at local auto parts store.

These details will help.

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  2. Fiat was founded in 1899 by a group of investors and since then it has become really popular. The free auto repair manuals pdf for Mitsubishi in some of the websites.