Runewolf1973

I get the ever-common ticking engine noise at start up, but it mainly only happens when it's cold out and only for a couple seconds. Some people say it will cause premature engine wear, but I'd like to know how much of this is actually true or not. I have heard from others that with these types of engines, that lifter sound/ticking at start up is perfectly normal just because you can't defeat the laws of nature and the oil will always drain to the bottom. They say that even if the oil drains to the bottom over a period of time, there is always going to be sufficient residual oil left on the internal components to prevent anything from actually causing damage. Is it possible that the effect of finding a different filter or oil that won't cause this is more just psychologically beneficial (eases the mind to not hear it) rather than actually necessary, or is this engine noise truly something to be concerned with? Interested in hearing what the rest of you have to say.

jereb83

I used to have a Grand Cherokee with a 4.0L and it did the same thing. This ever so slight tapping noise when I would start it. After a few revs and some warming up, it would go away. Can't say it was causing any problems. I tried all the supposed fixes...Marvel's Magic Oil, etc, but it never went away on its own. Then I traded it in. All the GC forums said it was normal noise. I am not too familiar with the 3.8 but I would bet its the same thing....if this offers any solace, my gf has a late 90s Ram with the 6.1L and guess what...it makes a tapping noise in the morning. Maybe it's a Chrysler thing...

Runewolf1973

Come to think of it, I think all of my previous Dodge/Chrysler vehicles did this. Maybe it's just that I've never really liked any of my other vehicles as much as I like the Jeep so I never really noticed or cared. I've never had a vehicle before this where I felt compelled to go on a forum and spend hours reading and hearing stories of other people's problems and their fixes. On a forum like this you get to hear all the worst case scenarios like "my transmission caught fire", or "my engine exploded"... It freaks me out hearing this. Thus when I am driving I tend to notice every little creak, tick, or burp the Jeep makes. Problem is, Jeeps are just plain noisy by virtue of their robust design and I just have to get over it.

Runewolf1973

You know it's kinda funny because just in the last few days I've noticed so many older vehicles driving around where the engines would make a constant noticeable "tap..tap..tap..tap..tap" noise. Maybe their engines are dying....or maybe it's just normal. Thanks for the reply.

jereb83

I don't know. I remember reading for the 4.0L that because it was a design that Chrysler kept adding new things to, the tapping was just a result of new features on an older engine. I can't vouch for that, but it sounded good at the time so I didn't worry about it anymore. My gf's truck is a different story though. That Ram's tapping is definitely noticeable and doesn't always go away, but her dad kept that truck up and they told him it was no problem. Chrysler man...

Runewolf1973

FWIW I found a segment about this sort of thing on Wikipedia. It sounds kinda like this is what is happening....

As quoted from Wikipedia: "There are a number of potential problems with hydraulic lifters. Frequently, the valvetrain will rattle loudly on startup due to oil draining from the lifters when the vehicle is parked. This is not considered significant provided the noise disappears within a couple of minutes, typically it usually only lasts a second or two. A rattle that does not go away can indicate a blocked oil feed or that one or more of the lifters has collapsed due to wear and is no longer opening its valve fully. The affected lifter should be replaced in the latter situation."

JKlad

In my opinion, the only reason why start-up rattle may be more of a concern nowadays is because modern bearings in gasoline motors have had the lead removed from the alloy for emmissions reasons (lead makes tougher & longer-lasting bearings but kills cat converters) so they are more susceptable to damage from dry starts. Lead is stil found in diesel motor bearings (diesels aren't subject to as strict emmissions regulations as gasoline motors at the present time, though this is rapidly changing) since these motors undergo far higher operating stresses.

I've literally run old (as in 1970s & '80s vintage) gasoline motors with lead-alloy bearings bone dry for like 20 miles with the lifters clacking away before I topped up the crank case & they've gone on to do 50K or more miles with no issues. Seems that the second the JK's 3.8l oil pump sucks air, the bearing spins & you're up for a new short block. A lot of this also has to do with the modern "emmissions-friendly" oils, that are extremely low in anti-wear additives. These additives (mainly zinc & phosphorous) come into play to protect motor components when shear occurs during extreme opetating conditions however they also wear out the precious cat converters a little bit faster.

My solution? I now run a thick 15w40 oil of a superceeded API spec that's full of "poisonous" anti-wear additives, and my JK runs smooth as silk & never rattles at start-up.

Incognito

There's also considerably less insulation around the JK engine than on most other vehicles. The exposed engine equates to more audible noise, so the tick is more apparent than would be on other vehicles where you have lots more components surrounding the engine & thereby insulating the sound. For example, say you were to put the 3.8L under the hood of a Cadillac and started it under the same conditions, I'd bet you'd barely hear it in the Cady, if at all.

Smevans

Its the mice running our underpowered engine banging to be let out.