Hello. I own a 1989 2-door Montero. It has been in the family since it rolled off the lot in 1989. Today we are faced with a decision about whether to part ways with a vehicle that has served us well.

The original engine failed in 2006 at 137,000 miles. At that time I had a rebuilt engine installed. The vehicle has not run the same since: a rough idle and a persistently intermitent ticking. The head in that engine cracked within a year and was repaired. The mechanic addressed the lifter valves in response to the ticking at that time. Didn't solve the problem.

Now the head gasket has blown out at 20,000 miles. I am reluctant to put any more into this engine. I am very fond of the vehicle and would not hesitate on the repair if I had confidence in the engine. However, I fear that I am just borrowing time until the next failure. The mechanic agrees. While there is no visible warping in the head or block, the cylinders are scored and the jet valves are failing. I don't know exactly what that means, but I do know the engine is at the end of its life.

Please consider this an open plea for advice: Does anyone have similar experience with the Montero engines? And advice on how to approach the existing repair? Or is the Montero platform receptive to another engine? Is there a shop that could handle the modification?

I am very fond of the vehicle and will consider any practical solutions, with one exception. I don't have the skills, time or equipment to do the job myself. I need a professional solution.

Thanks in advance for your thoughts.

Scott

 

Can you hear me now? Anybody? Any thoughts at all??

 

I’m in a similar boot. I have a 2002 Monty Sport LX 3.0L that I drove off the lot that now needs work after almost 300k moles. It’s been such a good reliable rig, I just don’t want to give it up.

I looked to replace the engine, but there are no rebuilds available. All my trouble is in the heads, so I’m looking to just replace those right now.

I’ll be giving it to my kid when it is running; good/safe ride for a 16yo.
He wants to convert it to electric…. I’m not against it, but I don’t know much about doing it. I going to look around to see what it takes to put an electric motor in mine, maybe that’s an option for you too.

 

I also have an 02' Monty Sport 3.0, and would love to make it electric! Here's what you need based on my research so far, but not complete.
1 - Traction motor capable of similar power output. This will be measured in Watts, sometimes with a HP conversion. This will not be cheap, usually around 5k to 10k for a good one. Options include a DC motor which is usually heavier and slower, or an AC motor which will be lighter and produce more power. The AC motor will need an AC/DC power converter, but usually come pre wired to generate power when you brake, thus creating a more efficient system over all.
2 - Motor controller. This should be sold with the motor, if not from the same supplier.
3 - Batteries. There are options here, but this will be a major expense for the project. Often EV batteries are cooled with a similar set up to the original engine, so keep your radiator.
4 - New computer. Often the computing requirements for this system are able to be accomplished by a general laptop. The biggest issue I have seen is a lack of programming avaliable on the market.
5 - Accelerator potentiometer. options include a modern vehicle accelerator petal, or a potentiometer kit that attaches to the existing throttle cable. Both of these will output an electrical signal to the system, sometimes directly to the motor controller.
6 - Small electric motor for the vacuum brake boost so you can stop. On the Montero you will also want an electric power steering boost. Your AC system will need to be converted to electric as well. I have seen electric AC compressors on the market recently with the popularity of electric cars. You will also need an electric Radiator fan.

I am trying to see what the newer Mitsubishi PHEV vehicles use for steering, AC controll and traction, as I feel these components will be easier to adapt to an older mitsubishi vehicle. Since our Monteros have individual drive belts for the different accessories, I am going to slowly upgrade the individual components to run off the 12v system before going full electric drive. I am also planning to run a small generator to power the electric drive motor(s) since the batteries are such a steep expense. After a battery install, I would be able to use the generator on long trips and not need to stop and charge unless that is convenient for me. I have not done the calculations yet, but the drive motor needs to generate the power needed at the wheels, which is the rated power for the motor times the gear ratio in the transmission. Some projects mate a DC motor to the transmission via a custom plate.
I have seen 100HP AC motors that only weigh 98lbs. There is a company working to produce a drop in kit for '1 ton' trucks (F-350 size trucks) that uses an electric rear axle and a generator motor, and are claiming a 10% fuel reduction. Edison Motors out of Canada. I have been waiting for Protean motors to sell to the public. They have a drop in 100HP AC motor that fits inside a 17" rim and is almost a complete set up as is. Their first project 10(?) Years ago was a newer Mini Cooper with 4 wheel motors and a small generator described as roughly the size of the spare wheel.

 

As for an engine rebuild, you can pull one from a scrap yard. The VIN number on your vehicle will tell you what your engine code is. (I cannot remember what digit) Match that digit with the scrap vehicle and the engine will drop in. Get the scrap engine rebuilt, or do it yourself.
For an engine swap, I was thinking possibly a Tacoma/ 4Runner 4.0 V6 engine, as those are also super reliable and parts are abundant and cheap. You would need the engine, ECM and most likely a transmission for it. You might also need a new Radiator to cool the larger engine, possibly a new rear differential to handle the power.
the Engines in the Monteros were developed along with Dodge, and Dodge used them in 'every front wheel drive V6 platform for 30 years' (70s - 90s), think Dodge Grand Caravan. Those engines have a coolant port and one other spot that is not identical to the 6G72 engines! If you are having problems finding a part, look for a similar MOPAR part, but I dont know what vehicle you would need to look at, as it seems to be random. The Montero sport apparently uses an older Dodge RAM (Dakota?) transmission (code?), side mirrors from a Jeep Grand Cherokee fit 100%, Grand Cherokee headlights fit 99%.
I hope some of this helps.

 

It sounds like the rebuild was not done well. Did you do it yourself or an engi e shop did the rebuild?