2.5 Common Problems

[Master7122]

I might be buying a comanche with a 2.5l and just wanted to know what some common problems or things to look for are before getting it. It has 85k miles and is 2wd 5 speed

[Pete M]

specifically about the 2.5 engine?  or MJs in general?

[Eagle]

What year?

 

1986 through 1990 were throttle body injected. 1991 and 1992 were multi-port injected. I believe it was '87 through '90 that the clutch used a combination release bearing/slave cylinder assembly, commonly referred to as the "internal" slave cylinder. They are a bit pricey, and replacement requires dropping the transmission and bell housing. Unfortunately, I don't know of any way to check one, other than to look for brake/clutch fluid dripping out of the bell housing.

 

The timing chain in the 2.5L uses a tensioner. Those wear out, but 85k probably isn't enough for that to be an issue.

 

Check the floors for rust -- both from underneath, and under the carpet/mat, if you can get a sense of what's going on from the topside.

 

Check the frame rails under the bed in the area of the forward leaf spring hanger brackets.

[Master7122]

specifically about the 2.5 engine? or MJs in general?

Just the 2.5, I've had 4 other Comanches with the 4.0 so I'm very familiar with them, just never had one with the 2.5

[Master7122]

And the year is 87' its rust free that's why I'm considering buying it

[mnkyboy]

Nothing really big with the 4banger, normal maintenance stuff and it will go for a long time.

[dasbulliwagen]

The 2.5 and 4.0 are closely related and share several parts. Any issues that are common to a 4.0 base engine are common to the 2.5 as well. The 2.5 doesnt have the 2 piece rear main seal though so if thats an issue the trans will need to be pulled to change it. Otherwise it will run forever just like a 4.0. Just remember to keep power expectations low, and you won't be too disappointed.