How does this engine sound?

sbq644

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Original poster
Joined
May 30, 2026
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Location
CA
Hey yall,

Looking to buy a 1999 jeep TJ sahara - completely rust free , 4.0 inline 6 with the 32RH auto transmission, with just under a 100k miles. Interior is damn near mint condition , and exterior is as well. It has 3” lift and suspension appears to have been well done, drive great and shifts without issues. Southern california jeep with no rust.

Seems like a really good deal!

The only thing i noticed is that the engine running a bit louder than other jeeps I've test drove. No knocking or anything , but kind of like a sewing machine sound. The seller let me know that he got he cracked exhaust manifold fixed recently. Also hear a faint rattling/scatching sound like a liitle flake of metal is being blown around (hard to hear in the video)

Hoping to get some feedback from yall! Reading that it could be a piston slap?

here is a video of the engine sounds and over all basic inspection of the jeep.


View: https://youtube.com/shorts/PLQDsJDsZlc?si=DdEsDcjPAgUrnnCT
 
My guess is the exhaust manifolds aren't on correctly or there is a crack. The seller of a 99 I owned for a short time said the manifold just needed tightened up. I found a giant crack in the manifold after getting under the rig and giving things a look.

Consider checking where the manifold bolts up to the exhaust as well.
 
Look at the manifold and see if it's new. I had a shop weld the cracked manifold on my 98' and it just cracked in another spot. Talk him down on the price because of that and the badly worn tires.
 
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Ask if you can have your garage look it over if you question anything. It’s a nice looking Jeep,but like The Boogieman stated you may find other issues to talk him down. I buy most of our company vehicles and two that I didn’t had some expensive issues that most likely would have been caught upon inspection.
 
It sounds like an exhaust leak to me. Either the seal didn't seat right or there is a crack on one of the collectors.
 
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The motor doesn't sound like it's running rough or anything like that. It's just the bit of putting sound making me think exhaust. I'm sure sounds louder in person than the phone captured.
 
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Reactions: TJ Jim
Hey yall,

Looking to buy a 1999 jeep TJ sahara - completely rust free , 4.0 inline 6 with the 32RH auto transmission, with just under a 100k miles. Interior is damn near mint condition , and exterior is as well. It has 3” lift and suspension appears to have been well done, drive great and shifts without issues. Southern california jeep with no rust.

Seems like a really good deal!

The only thing i noticed is that the engine running a bit louder than other jeeps I've test drove. No knocking or anything , but kind of like a sewing machine sound. The seller let me know that he got he cracked exhaust manifold fixed recently. Also hear a faint rattling/scatching sound like a liitle flake of metal is being blown around (hard to hear in the video)

Hoping to get some feedback from yall! Reading that it could be a piston slap?

here is a video of the engine sounds and over all basic inspection of the jeep.


View: %5BURL%5Dhttps://youtube.com/shorts/PLQDsJDsZlc?si=DdEsDcjPAgUrnnCT[/URL]


I think 99s still had good pistons?