Montero Crankshaft Pulley Bolt Loosens ???

First a few questions..

1) What year, model and engine are we talking about? 2) Does the 'mechanic' work at a dealership? Or just a local garage?

Now some information. There is a known problem with the front crank bolt on the 1989 thru

1996? 6G72 SOHC engines. Mitsubishi redesigned the front crank bolt and issued a technical service bulletin for the 1992 thru 1996? 6G72 SOHC engines. Mitsubishi did not include the 1989 thru 1991 6G72 SOHC engines. But, the 1989-1991 engines have seen the same problem.

The problem is that the front crank bolt begins to loosen. This allows the pulley to become loose, then wobble. A lot of times the crank is damaged. Some times the bolt breaks off in the crank. If it is caught early, everything can be repaired. Once the bolt breaks or the front of the crank is chewed up, the repair price goes up a lot.

To answer your question about the 'sloppy job' causing the problem. If you consider it sloppy that someone did not know enough about the engine to replace the bolt. When it's fairly common knowledge that the

6G72 engine has this problem. Even Mitsubishi issued a TSB that covers most of the model years.

A good mechanic or a Mitsubishi dealership should replace the old designed bolt with a new bolt whenever the timing belt is done. The new bolt is in the $5 - $7 range. It's cheap insurance.

Go over to

There is a great online forum there for Mitsubishi truck owners. Do some searches on 'crank bolt'. You will find everything (and more) that you wanted to know. Everything after the @ is spelled backwards.

Our '90 Montero two years ago had that bolt fall off. It chewed up the crankshaft to the point they could no longer just put the pulley back on. I was quoted about $5,000 for a new engine ($4,200 for a rebuilt). The only place I have ever had the SUV worked on is at a Mitsubishi dealership. I sold the Montero to the mechanic for $1,000 (Blue book was about $3,500 - $4,000).

I bought a used '96 Montero and just a few months later received the service bulletin. To this day I think if I had known then what I know now and had pressed the issue with a lawsuit I could have gotten the engine replaced under warranty.