Hey everyone,

Just changed my oil in my jeep Cherokee 4.0 with Mobile one synthetic and mobile one oil filter. Also put a whole new exhaust on header back about a month ago or so with 2.5 inch exhaust and k&n air filter. So tonight I noticed a slight ticking sound when I was in park. (With some throttle) I can only hear it when I start out like when its in 1rst and 2nd gear. Its a automatic. I don't think its exhaust but I could be wrong.... I heard lifter issues, flex plates, exhaust ect... Wondering if anyone has any ideas what it could be.

Has 100,009 miles one it and its a 98

 

First; If that K&N's an oiled filter get rid of it.
Second; if you can, a video will be a ton of help. But I think it's most likely the lifters not getting along well with the oil, which is very common. Just ignore it for now and try different brands/types of oil to see which is quietest. I used to run Royal Purple, engine was nice n' quiet. Put Mobile1 in, ticked like someone was tapping the engine with a screwdriver.

 

I like Mobil1 but your oil is what you changed. Use something else.

 

Ok that's what I was thinking. I just switched over with Synthetic oil too. Yes it sounds like someone is tapping on the engine with a screw driver. Im sure it could just be a common sound too with the 6.0. I wish I could get a video but, it wasn't loud enough to hear.

 

Ever used mechanic's stethescope before? Like a medical one but has a solid probe on the end. Best thing to do is figure out WHERE the noise is coming from before spending more money. I could say do X, Y, and Z but it would just be a guess

 

Yea I've heard of one. I could just pull the valve cover and check the lifters. I'm pretty sure its not the exhaust header but I'm going re-torque the bolts down just to make sure. But its a slight tapping sound. Just noticeable when its given a small amount of throttle. Like starting out in 1rst and 2nd gear. I'm thinking its just the cold start-up (Michigan weather) and just the new switch from conventional oil to synthetic.

 

Lifters are way down in the block by the camshaft. You have to pull the head to extract them

 

Correct. What I meant to say is by pulling the valve cover to check the rocker arms where the lifters contact rocker arms and valve stems

 

The Jeep 4.0 is not a quiet engine by any means, they make more noise than most modern engines, but they will make noise for hundreds of thousands of miles without any issues.

 

Is there such a thing as a QUIET 4.0? If you get too obsessed with listening for noise it will get louder and louder!
Below 210 degrees synthetic oil is thinner than dino so the thicker dino will mask the noise somewhat. So which do you prefer; engine clearance noise masked by gunk or lubricated (the way it should be) by free flowing oil.

 

I don't like synthetic oil at all. And you really shouldn't switch a high mileage engine over to synthetic. I know 100k is nothing for the l6 but still.

I would suggest sticking with regular old oil. What are you really going to gain by going synthetic? Not much besides a bunch of new oil leaks...

 

This is true.... I just changed the exhaust so I'm constantly listening to the different noises haha. I totally agree.

 

I know when mine has been sitting for an extended period of time..and its cold (40 or lower) I will get a ticking noise when it's started and it will go until it's warned up...turned at top be the purge valve

 

Proof (Yes i know i had a vac leak)

 

Mine isnt that loud at all. Mine is like that but just a quieter version of that.