JoeRif

I searched posts and most are dated back before i2010 and nothing I found sounds similar to my issue. I have a 2008 JKUS with 38K miles. Don't use it very often - obviously. I started my Jeep the other day and holy guacamole, it sounded like I had a bad valve tap or cracked manifold. The ticking was very noticeable. It seems to quiet down after it warms up for a few minutes, and don't hear it after I start driving - only at cold startup. I therefore dismiss the idea it's a manifold / exhaust issue, but am now thinking its a lifter or valve tap in dire need of a hydraulic rinse. I just changed my oil and added STP oil treatment - thick honey-like goop but it still makes the same tapping sound. Anyone else have this exact issue? What is it ? How to fix? I absolutely hate the sound, but also hope it's not a big problem. I do have a lifetime warranty on drivetrain so it should be covered if an issue. The Jeep is well maintained and never been off-road or stressed. Thanks

tribulation138

Defiantly sounds like you need a valve adjustment. Or something wrong with rocker arm. But with low mileage you shouldnt even be close to valve adjustment. But it is a Chrysler anything can happen..

Get it checked out if you have a warranty.

14Sport

Agree with trib...or oil pressure issue. The thicker the oil, the longer it takes to warm up.

JoeRif

Thanks guys. I do use 5W-20 as per the owner manual. I will call to make an appointment with dealer. They usually operate with a 2 week lead time so it will be a couple of weeks before I know what the issue is.

Jnorman831

Guys the lifters are hydraulic!! There's no way your going to be able to do a valve adjustment because there's no lash between the lifters and valves. The tapping on start up is because a couple of lifters are being compressed the entire time the engine is turned off. When the lifter is compressed it pumps out all the oil of the lifter. Then when you start it back up it has to refill with oil and that's when the tapping goes away. If you take your jeep to the dealership and ask for a valve adjustment they will take your money and fix nothing. I guess it is possible you might have bad lifters but thats a rarity.

JoeRif

Jnorman831 - thanks for the info. I never had a tap before so something must've changed.

14Sport

I have hydraulic lifters in my 1970 Vette and never have experienced that either.

JoeRif

:thumbsu

I have a '68!

101gargoyles

You old 'vette guys are talking apples to oranges engines. Yah things have changed since the old days. Haven't had to change out plugs/cap/rotor/condenser on my '08 yet....Yah it ticks on start-up...END OF THE WORLD as we know it
Lots of folks these days are worried about noises that mean nothing except normal operation. If it breaks then fix it.

RoysRig

My Rubicon has done this almost from day one. And you are correct, it has a lot to do with where the lifters ended up when the engine was turned off and how long the vehicle sits before the next start up. If they are in a compressed state and the oil has drained out then it will take a few engine revs to get the oil pumped back up to the top to come back down into the lifters. LSx engines when you do a new lifter install you are suppose to soak the new lifters in oil for 48 hours ahead to let all the air escape so that you don't have a completely dry lifter on start up.