Jeep Wrangler - Knocking Sound - Question - Video Inside

Hi everyone,

I’m fairly new to the wrangler scene, but have run into a problem with my wrangler.

2004 TJ Wrangler Manual, Petrol. 100k kms

I bought it about 3 weeks ago, and the engine sounded great - not an issue. I changed the engine oil about 2 weeks ago, and since then it has a loud knock. (5.7L) - 5W40.

The knock is loudest on a cold start, and eventually after 30 min of driving, quietens down to a ticking sound. Sometimes (rarely) it disappears all together.

I changed the oil again to 10W40, but still no fix.

The car has no loss of power, and seems to drive fine.

I’ve managed to record the sound and how it looks, any ideas or diagnoses?

Thanks heaps in advance!

First off.

10W 40 oil is thicker than 5W 40 oil during a cold start. So that’s not helping.

Try changing the oil filter. Maybe there’s a problem with the anti drain-back valve and by-pass valve in that new oil filter.


Yes, changed the oil filter both times. Still nothing.

I take it that you have a Chevy small block conversion. In the US,for many years, the oil recommended for that engine has been 5W-30. In fact, the owner’s manual for he '89 Suburban I owned with that engine specifically warned against using 10W-40.

Could be piston slap. The piston skirt is slapping the cylinder walls. When it warms up the heat causes it to expand and noise goes away.

That sounds like a lot of valve train noise and there doesn’t seem to be any oil flowing in the top end, how is the oil pressure?

Looks like a 4.0 L Jeep engine in the video, the oil capacity is 5.7 Liters (6 quarts).

The oil gauge looks fine, but I’m not sure how accurate those are.

Is there damage in driving it? Or will it stay as it is?

In other instances where the top end has oil it still knocks similar