Thanks, Jeep Man. I've always used synthetic oil whicH I guess helps cut down warm up time, but I don't know for sure. Those portable magnetic heaters are an interesting idea but not that feasible, it seems, given my apartment's lack of outdoor outlets.

 

Multiple extension cords jk

Yes, a synthetic oil can cut down warm up times quite a bit, and as well flow better when cold. Mobil 1 has a video on youtube where they subject a quart of their oil and a standard oil to a really cold temp, and the Mobil 1 still flowed well. And the heater idea is more for preference. Your 4.0 can still heat its own oil the usual way; an oil warmer simply assists when it's really cold. As long as your engine has the minute or two it needs to warm the oil enough and get it flowing, then you're good.

 

Ha, the thought had crossed my mind!

 

I have this same issue with my Xj except it makes a ticking/knocking noise almost all the time. I have a decent stereo so it never bothers me, but ive read elsewhere that it could just be old lifters making noise. I'm not sure if it's something to worry about right now but it seems to be running just fine as a DD for me.

I could imagine that this seasons temp extremes could be somewhat to blame for the rough running conditions. Today in turlock ca, first it rained overnight, cleared up by 8am for work and was sunny at around 65 degrees and pretty dam windy, possibly 25-30mph, untill 1pm when it got ridiculously cold (around 35-40 prob) and then started to hail heavier than I have ever seen before in this area, enough to cover cars and rooftops to look like snow, which never happens here.

This went on for about an hour and then again cleared up by 3-4pm. In one spot around this time you could look south at the sky and on the left was dark rain clouds and a massive rainbow, and on the right was white clouds and blue sky with the sun still shining... I dunno what the hell is goin on around here, maybe it's got to do with 2012 comin up lol

 

2012 shouldn't bother Jeep owners. Just fit a snorkel and a raft to the underside of the body, and we'd all be fine.

As for your noise, the 4.0 is a VERY noisy engine; and plus it really doesn't help that the cabin isn't exactly soundproofed. Your ticking could be the famous Jeep lifters or even the injectors pulsing. The knocking could be a multitude of things, with my first guess being your flexplate to torque converter bolts. Take about an hour one day and jack your jeep up, remove the tranny inspection cover, and tighten those bad boys up (28ft lbs if I remember correctly.) This only applies though if you have an automatic tranny.

 

Are either of those issues worthy of repairing if they've been like that for a while? I don't have the expertise to do that stuff myself nor do I know anyone locally who can help, so I'd have to take it in somewhere. But as my DD, I want to make sure nothing critical goes without resolving. My acceleration has been sluggish as of late and I'm not sure if it's related to either issue (the ticking has been going on for 4 years now and the knocking has been relatively recent).

 

Any noises will be louder when the engine is cold. As the engine warms up, components expand. Oil pressure is created by the large/small passages that the oil travels in (it's not created by the pump. Different pumps my provide more volume, but they don't create oil pressure). As 'gaps' between components decrease (expansion of parts via heating) the oil pressure will further increase (less space to fill with oil equals higher pressure. If the pressure gets to high, the pressure regulator opens).

This can really be heard as the pistons warm up. On super-cold days the pistons are smaller and the rings will have a slightly larger gap away from the sides of the cylinder causing some noise as they 'rattle' up and down the cylinder. The engine block and pistons warm up, tada, the rings/pistons/cylinders are happy again.

Idling time vs drive time is not relative if the engine is working as it should. It's all physics.

 

I agree with that.......Piston slap would be my guess and as the skirts heat they expand some and lessening the slap.
The 99 I got for my dad a cpl of years ago does the same thing as yours and has since I bought it. Let it warm up about 10 min and it quietens right up. Tried different viscosity oils with no change, still had to let it warm up for same amount of time before it was quiet.

 

I switched to rotella 15/40 and now instead of a clack sound it's more of a tick sound... but I have 245k miles

 

Your right, my Xj with over 250k does this at warm-up. Actually a lot of the cars I've owned with high miles have done this, even the higher compression 1.8l v-Tec Honda, which i sold for my current Xj haha

The only thing is that my engine continues to make the ticking noise after it has run awhile at operating temp. This still leads me to think that it would be the worn lifters complaining under the head cover.

So I'm thinking a once through with good engine oil cleaner, to get all the sludge out of the passageways, and an oil change to a slightly heavier weight oil, would possibly help to make the engine run smoother? Or is this something that will require taking apart the entire engine head to fix entirely?

 

allright everyone this noise got worse today and now does it when warm. so started to pull motor will post what i found when i am done. and the flex plate bolts were tight so it wasnt a loose flexplate. wich i was hopeing it was!!!!!!

 

Exhaust leak? I started a thread this morn on what I thought was for sure broken rockers, rods, or something. Went to my mechanic, and he showed me how the collector of my header had nearly cracked all the way around. The sound I was hearing was a bad exhaust leak. I was shocked.

 

Keep us posted, I'm sure there are plenty of people thinking the same things. Just recently my jeep has been clacking away louder than normal, but it sounds like it's coming from the the lower portion of the engine.... probably just telling me everythings alright

 

well got the motor pulled today and its not the flex plate or a craked manifold so tomarrow the tear down begins

 

keep us posted many of us want to know what it is