What is this engine sound? (video)

[Justanotherjeepguy]

150K is not a lot of miles or way too many all depending upon past history. If you know it has been well maintained and operated its whole life, that says a lot. Tests such as oil pressure, vacuum, compression, cylinder leak down tell a better story as well.

It seems to have been maintained exceptionally well—no rust, sun damage, scratches, etc. Looks like it came from the dealer, inside and out. But as far as how it was operated (or if they managed to change the oil on schedule), there’s no telling. Unfortunately, there weren’t any maintenance receipts or records.

I’ll definitely have those tests run though. I’d like to know how it does.

 

[bromel]

I have the same noise on my 4.0. Quiet on startup, then the noise appears only at idle after about a minute, and it lasts until the engine is fully warmed up and goes away. Almost certainly the lifters. My old Cherokee has had the same noise for nearly 175,000 miles. You also hear them chatter after starting the engine hot. Different oils affect the sound in varying amounts. IMO, not worth tearing down the engine for a little bit of lifter noise.

 

[Flivver250]

I am a big fan of overkill. Moderation is for monks. That said, many noises turn out to be less trouble than you would think. Lifters and timing chain replacements can be considered normal maintenance, not a repair. You don't buy a new pair of shoes every time you need new laces. That said, if maintenance or repairs are approaching the cost replacement, a cost benefit analysis almost always comes out in favor of a reman with a warranty.

 

[Mjv]

Go for it. take your time. Think about what you doing. If your not sure, stop and think it out. If your still not sure, ask. You'll do just fine. Half the uncertainty is because you haven't done it before. The hardest part is making the decision to go forward. Good luck!

 

[Justanotherjeepguy]

Fixed! The ticking is gone!

As one of the commenters guessed, it was both the lifters and the timing chain. I did the lifters myself, which took about 3 hours. It would’ve take much less time, but I accidentally dropped the lifter closest to the firewall sideways when removing it, so I spent about 45 minutes trying to fish it out. The lifters only fixed part of the noise, so I decided to go ahead and have the local shop do the timing chain. It took them about four hours, and the total was just over $450 with tax.
I think the timing chain might have been in really bad shape. Though it could all be in my head, I really do think there’s a performance difference. I noticed a difference when idling (the RPMs seem more steady) and when accelerating (a bit more power, and seems to react faster to the gas).

Thanks for the help everyone! She nearly sounds like a new Jeep!

 

[mushdogs]

Fixed! The ticking is gone!

As one of the commenters guessed, it was both the lifters and the timing chain. I did the lifters myself, which took about 3 hours. It would’ve take much less time, but I accidentally dropped the lifter closest to the firewall sideways when removing it, so I spent about 45 minutes trying to fish it out. The lifters only fixed part of the noise, so I decided to go ahead and have the local shop do the timing chain. It took them about four hours, and the total was just over $450 with tax.
I think the timing chain might have been in really bad shape. Though it could all be in my head, I really do think there’s a performance difference. I noticed a difference when idling (the RPMs seem more steady) and when accelerating (a bit more power, and seems to react faster to the gas).

Thanks for the help everyone! She nearly sounds like a new Jeep!

It’s not in your head. I fell in love with my four angry squirrels all over again after replacing the timing chain and gears. The little critters had some get up and go I didn’t know they had when I bought it. 5th gear suddenly made sense.