I've noticed that the engine on my new (to me) 2007 Wrangler sounds a bit "thrashy" on startup. I was wondering if this was normal for the 3.8 liter or a cause for further investigation?

Thanks!

 

If it happens for the first few seconds (especially when cold & the Jeep's been sitting for a while) & then goes away quickly, then it's probably the anti drain-back valve on the oil filter allowing it to empty. There's been quite a few threads here about certain brands of filter being worse in this regard than others. Mine only does it if it's been sitting for a few weeks (Mopar filter), but yeah I agree it sounds kinda scary if you don't know what it is, & you half expect a piston to come flying out through the hood!

 

It seems like it happens after it's been sitting overnight or longer. It doesn't sound like the engine is going to fall apart, just rough. It only lasts for a second or two.

 

Yeah, sounds like the drainback valve then. Here's a thread with some info on different filters...

https://www.jk-forum.com/forums/show...ght=oil+filter