On Christmas Eve, my jeep was a little too excited to wait another day to give me the gift of engine knock. The jeep used to have lifter tap, audible only from above, and now has a knock audible all around the engine and from down the street. I've done lots of reading over the past 3 days on the issue and either I'm missing the point or reading incomplete material, so I have two questions: regardless of what the culprit is, am I correct that any of the possible causes require the engine to be pulled to fix or replaced? Secondly, do I lose much resale value in waiting until the motor truly blows to sell it versus selling it now while it runs but has an obvious terminal condition?

Manual, so no torque converter. 218k miles. No CEL, no carbon buildups on exhaust to indicate leak, shook cat and no rattles inside, all bolts on exhaust manifold checked and are tight, low compression in ALL cylinders: #6 -90; #5 - 65; #4 - 85; #3 - 95; #2 - 80; #1 - 60. I never really noticed a reduction in power though I live in Colorado so the altitude makes the jeep always sluggish. Sometimes it also feels like I'm driving into the wind, usually it's because it's windy. Knock is rhythmic and increases with RPMs, I'd estimate 6-8 knocks per second at idle, seems to get worse when decelerating and also kind of peaks and sputters after I let off the gas or depress the clutch.

 

That compression is really low. I've heard of people doing a pretty good job of rebuilding motors inside the vehicle, but I imagine everything else is also wrecked if your compression is that low. Bearings on the cam and crank, as well as the cylinders themselves.

You can also just throw another motor in there if its in good shape. You can get 4.0Ls cheap. Take it to Edgewater Jeep on 44th & Sheridan and see if what they price out a new motor or rebuild or used swap. I had them do some light work on mine and seemed like good dudes. Small shop.

 

Between trying to sell it as is or wait till it blows, it's about the same. The knocking motor is junk so there's no real waiting till it goes to sell it.

 

Thanks for the opinions, gentlemen, that exactly answers my questions. And thanks for the local suggestion KGM. I'll see what they have to say before I decide what to do with it.