Mishi's Blog: FYI on mitsubishi and Timing Belts

[J-MISHI-R]

If you own a mitsubishi or have friends who own one, you will have heard them make mention of it.

Others may have given you horror stories about them bursting, with disastrous results....

All Mitsubishi engines are known in the engine world as "interference engines". On an interference engine, if the timing belt slips even one notch, the piston can crash into an open valve causing serious engine damage by bending valves and breaking pistons.

This of course is worse based on how high the engine was running at the time.

Belt type

All mitsubishi vehicles carry different sizes of belts, From narrow, close teeth belts, to wide open teeth belts. Some cars such as the Evolution, carry another, smaller belt, called the harmonic balancer (or locally balance shaft) belt. Most mitsu engines carry a belt width of 29mm, others 22mm.

Mitsubishi's OEM belt manufacturer, is UNITTA, which is made by the Gates Company. When looking for a belt, this brand should always be your first choice.


Change Intervals

97% of the time a Mitsubishi timing belt fails is due to the owner not changing the belt at the stated interval.

You must change your timing belt at the the 60000 Mile interval (96000 KM)

It is also good practice to change it before this interval for safety.


Inspecting and Installation

Always have a professional mechanic install your belt. if you choose to do so yourself, you do it at the risk of damaging your engine if you are not sure what you are doing.

As stated earlier, 97% of mitsu timing belt failures are due to not changing the belt at the intervals.

The other 3% are due to sub standard quality belts, untimely failure of a component in the drive (water pump, tensioner/ idle bearing), Contamination of the belt by oil or water and mishandling/ installation of the belt.

- When checking your timing belt, check the following



CHECK ALL YOUR OIL SEALS!!!! oil contamination (or water in the case of a pump) will degrade the quality of the belt and also cause it to slip if it is bad.

When installing the belt, do not crimp it (that is, squeeze it together at the ends where they loop) as this can pre damage the belt. It is good practice to replace all the bearings that the timing belt runs on. Most notably, is the timing belt tensioner pulley and in DOHC engines, the idler pulley. If you cannot afford these at the time, have them inspected and make sure that they are in good working order.

It is a good Idea to change your water pump as well, even if it is in good order. Most times, the water pump installation will not cost much more if at all, considering that you have o remove the belt to get to it. More importantly, your pump may be there as long as the belt and it makes no sense to change the belt, then one month later change a pump....Give yourself some extra insurance.

When reinstalling, there are what they call timing marks on the engine block and the sprockets which the belt runs on. These must be aligned properly before tighting. A misaligned belt can cause you to have abnormal performance and worst case scenario, you can damage your engine.

Used Cars and timing belts

Unfortunately, many people who want to buy a used mitsubishi never actually ask about the timing belt.

It is IMPORTANT that you do. That can be the difference between you enjoying the mitsu experience or shunning the brand.

Always:-

1. Ask the Owner if the belt has been changed and at what mileage

2. Look at the odometer for the mileage...

3. Ask the owner if at anytime the dash was replaced or failed in the case of engine changes etc. This is due to some engines carrying different electronic/ ignition systems and they may not be compatible with the existing dash. Also in some models digital odometers have been known to fail, which causes the owner not to know the true mileage...

4. If the engine was changed, and the belt was not changed, you must ask the owner what mileage the engine came with. Reason being that you may buy a car saying 70000Km on the odometer, and the engine is actially 40000KM OVER this....Knowledge is power....

5. Ask if the water pump has ever been changed and what interval.

6. Ask if any the owner had any water leaks at the pump area (as per "5" above) and if they ever had any oil seals changed. This will help you to do what is neccessary.


Well hope this lill blog proves informative for some of you...

Cheers.

MISHI.
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[Sanctifier]

Great post MISHI. Thanks.
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Walk softly... and carry a BIG stick!