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Discussion Starter · #1 ·
Hey everyone - so, I have a 2003 Wrangler Sport 4.0L that was in a wreck in January. There was no impact on the engine, just to the front passenger side. I replaced the fender, hood, grille, radiator and A/C condenser. Everything seemed fine. I noticed the PCM had been pushed back a little into the firewall as well.

After the wreck, I started getting misfire codes for Cylinder 1 and 3, but I'd add fuel injector cleaner to my tank, and it would go away, but it had been happening more and more frequently.

About a month ago, I noticed a ticking noise in my engine, and at the same time a knocking noise from underneath. I checked my oil, and was a little low (less than two quarts). I filled it, but ticking noise never went away. Then it started misfiring, and within two days it was running so bad that it felt like it would almost stall on me. I took it to a shop, and they said I need a new engine, but didn't give me much of a reason why except oil on two of my spark plugs.

I thought it might be the throw-out bearing in the clutch. Took it to a clutch shop, but they said everything looked good there. They did say I had a rear main seal leak, but that it wasn't bad. They also dropped the tranny, and the input shaft had a little play in it. I had the front and rear bearings replaced in the transmission hoping it would get rid of the knock. It made no difference.

A friend of mine suggested it might be the main thrust bearing on the crankshaft (because the knock goes away when I press the clutch in) since it gets worse after the engine warms up.

Additionally, I had a compression test and leak down test done to find out why it's misfiring (I'd already replaced the plugs and coil pack). Cylinder 3 compression is down to 30psi, and the leak down test proves it's not the valves. The thought it that its the piston rings? SO...

With all of that information, what would be the logical next step? I really don't want to replace the engine, but will if I have to. I'm wondering if these problems could be residual affects from the wreck. (And btw, the PCM failed 3 months after the accident. Thank god it was covered under warranty.)

I'm at a loss. Any help would be great. Thanks.
 

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well I have a couple questions. you said it was wrecked, did the crank get hit? if so I have hunch it got cracked and it may just now be failing. check the list of parts that it had replaced. if the crank pulley was replaced it was hit. sorry to say but that engine is so long the engine picks up load when crashed. it gets right in the way and the crank takes the brunt of a hit. if you open it up and the crank is broken check the block webs around the main caps for damage.
 

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good news, its a 4.0.

better news, they are CHEAP.


bad news is that your pretty far away for anybody to actually come help you do the swap.
 

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Discussion Starter · #5 ·
I don't think the crankshaft got hit. Like I said, there was no obvious engine damage. Just the surrounding components. I did have to have the idler pulley adjusted, but that was it.

I won't be taking the engine apart anytime soon. I can't find a decent mechanic in this town to do the work, and have no time to do it myself, so I'm forced to drive it as is and probably doing more damage to it.

Each of the 5 remaining cylinders tested between 150 and 170psi on the compression check. Weird to me that only one cylinder's rings would go bad.

I also have a bad o2 sensor in bank 1 sensor 1 (though I just had the same sensor replaced 9 months ago), and the Jeep is getting more and more difficult to drive. Can't even push it above 2800rpms. It makes me sad.
 

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Do you have the 0331 head casting? It is known for cracking between the 3rd and 4th cylinders. That may be why you have low compression in #3. Look next to the valve cover on the manifold side, between cylinders 3 and 4, the casting number should be there. Are you also slowly loosing coolant, with no signs of drips or where it is going?

pic of casting #

 
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