Seeking amc 242 help (4.0L)

[xjacob903]

This will be my first post on here. I'm seeking knowledgeable help from jeep 4.0 owners or engine gods.
I'm going to summarize the heck out of this.

So I had a cyl 1 and 6 misfire, cyl 6 went away, cyl 1 stayed. New plugs, wires, cap, nothing changed, swapped injectors, still nothing. Cleans the intake valves with spray... "cleaned" lol, nothing but carbon blowing out the rear. Well.. cyl leak down and compression test shows low comp on 1 and co2 in coolant. Well it drives fine! Just the cel is on.

So I took it to a dealership and they said this

It has no knocks, oil pressure is perfect, so how are the bearings bad? lol!

They quoted over 3k for head to be machined and main rod bearing replacement. But it runs FINE! 249,400 MILES currently. Well taken care of. I honestly think it's just a head, I knew that all along, but the rod bearing diagnostic is getting to me.

Opinions please

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[VCeXpedition]

What year is your jeep? Is this OBD 1 or 2? What is the CEL code? What is your location?

If you took it to a "Jeep" dealer, I can tell you that they don't want to work on it if they quoted you all this stuff, that's a strategy to make you go away.

Find a reliable shop near you that makes their living working on this kind of stuff and you'll be miles ahead.

You're doing the right thing by educating yourself, but if you can't do the work yourself you need to find someone you can trust. Web mechanics can't do the work for you, we/they can only make guesses as to your situation.

Don't discount your own knowledge or learning when it comes to getting it fixed right, and by the right shop.

BTW, your pic is upside down and hard to read.

 

[Rockwell]

"Well.. cyl leak down and compression test shows low comp on 1 and co2 in coolant"

according to what you posted sounds like a cracked head or seeping head gasket. Co in coolant it a tell tell sign then compression low on cly.1 gives it away. Shop around for a good machine shop or a new head then a shop that will give you a good rate or a buddy to help then do it your self.

 

[TerryD]

What year Jeep? Most 99+ Jeep 4.0ls are bad about cracking cylinder heads and if coolant leaked into the engine it could start wiping out bearings. We need more info to know how extensive things really are.

 

[Truck mechanic]

Just me .02, but with that many miles I wouldn't just do the head, time for a motor.

 

[Scott]

Imho if you're dead set on keeping the jeep I would just pony up for a new jasper motor. 4.0 motors are pretty simple to swap even for just your common shade tree mechanic can swap a motor in a weekend.

 

[xjacob903]

I forgot to add the basics. 98 xj 4.0l with about 249,xxx.

It runs great, no sense in a new motor. I just need to run for at least 2 more years of college! I'm sure it's just the head and money is very tight. I can afford the Clearwater head for 425

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[VCeXpedition]

Where do you go to school?, ask for some specific help on here and there may be somebody that would step up. I'm a Toyota guy, don't know much jeep stuff but there's a lot of experience on here.

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[xjacob903]

Grayson County in sherman texas. Working towards a radiology technician.

I guess my specific question is, why would the tech say rod bearings are going bad? They're either working or not

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[VCeXpedition]

Not sure what diagnosis led him to that conclusion but they do go bad, sometimes slowly. I cringe everyone my neighbor starts her Tahoe because can hear the rod knock from inside my shop!
And besides, like I said, if he didn't want the work, he's going to make it sound as bad as possible.
Wonder what would happen if you put up a post asking if anyone around you knew of a good jeep technician? You might get at least a decent reference.


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