2000 XJ 4.0L with a little under 94K miles. Has a new Alabama Cylinder head on it with about 4500 miles on it.

The jeep used to run nice and quiet, but recently I can hear a ticking from inside the jeep with the windows up and the radio off. The tick increases with RPMs and seems to be coming from the left side of the engine (when facing the jeep with the hood open). This Cherokee has the California emissions with the two pre-cats on the manifold, and so far no manifold leaks. I recently changed the oil to Rotella T synthetic 5w40 with a mopar filter. Before it had 10w30 conventional oil. I have good oil pressure, and oil looks good on the dipstick.

After I changed to synthetic I could have sworn the jeep sounded a bit noisier, but thought I was hearing things. Its about 25 degrees out and has been for the past week, the noise doesn't seem to change when the engine warms up, although some days it will come and go. Oil level is right on the full mark, and the synthetic has been in there about a month. Should I change back to conventional and run some marvel mystery oil through it? What could cause the ticking?

I searched but didn't see anything about engines ticking after switching to synthetic...

Sorry for the long post, its just annoying when my dad (who hates me putting money into the jeep) rides along and says "I think your jeep is ticking"

 

when you changed the head did you instantly switch to synthetic ? or did u install the head , run reg oil then switch . it may not be the oil it may be something to do with installing the head

 

I had a messed up wrist at the time of the head install so I had a mechanic friend put it on. The head was installed and he put in conventional 10w30 oil. I'm pretty sure it was Valvoline, with a napa filter. I ran that for ~3200 miles then changed over to the Rotella T synthetic 5w40. Driving home today I noticed that after driving the jeep awhile, it seemed a bit quieter. I usually drive about 16 miles to school, but on the way home I stopped at a friends house so it was more like 28 miles home.

I should add that my 0331 head never cracked. My dad had a friend who's WJ cracked the head and he didn't want the same to happen to mine so he agreed to pay half for the Alabama Head as a b-day gift. It was done as a preventative measure as I plan on driving this jeep for a long time.

I'm thinking that maybe the synthetic oil being thinner is whats making it tick, since when it got nice and warm today driving home it ran a bit quieter after the oil reached operating temp and got thicker(5w40).

I can't hear the ticking with the radio on low, but can pick it out when cruising down the road with the windows up and radio off.

Edit: and the new head has been on for 4 months

 

5W40 synthetic or conventional is thicker than 10W30 at normal operating temp. 5W40 is slightly thinner, when cold, than 10W30. I'd try switching back to 10W30, preferably 5W30 conventional, and see what happens. If the lifters were not changed, it may just be time for old lifters to start ticking.

 

the lifters were not changed at the time the head was put on. This motor only has 93,700 miles. My friend with an '89 XJ suggested running seafoam in the crankcase for 15 minutes before changing the oil, but right now I'm a bit hesitant to put anything in there besides oil. The 5w40 still looks nice and amber but this weekend I'll see if I can pick up some 10w30 conventional and see if it helps. Would adding a small amount of marvel mystery oil be a good idea or something to stay away from? I've only used it to free stuck engines on old tractors, never in the crankcase.

 

Honestly, If its just a small tick I wouldnt worry about it. All engines tick/make noise after a while. Hydraulic lifters are known to make noise. My girlfriends old Malibu had lifter noise at 122,000 and is still running good, the dumbass that bought it from them beats the hell out of it too. My Jeep has 205,000 miles on it and DOES NOT sound good, but it still runs good and is not low on power. We have narrowed it down to a worn cam and bad lifters.
As long as it doesnt sound like mine, I wouldnt worry about it too much. Its probably normal.

 

yeah that sounds like a knock mines definitely not that loud but its just annoying when people are like "whats that ticking sound?", when I know it wasn't there before...

 

I've been reading some threads on other forums but the info is kind of conflicting. Is there anyone who has had lifter tick and made it go away for the most part? It seems like some say that if marvel mystery oil or running a thicker weight oil doesn't solve it that the engine will tick forever unless the lifters are changed. I also read that it will eventually go away after changing the oil a few times. I guess it depends on the rig, so I'll pick up some 10w30 this weekend with some MMO and see where it gets me...

 

5w40?

are you crazy?


dude, 5w40 has no business being in a 4.0 liter. They are designed to take 10w30, and chryco's new specs say 5w30 as well.



do a darn oil change and stop testing the waters...and when you change the oil, use a synthetic/traditional mix for at least 5k miles. you can't just switch direct from dino oil...need to run a mixed oil first, even at 100k.

the ONLY time you can direct switch oil is on a new motor. otherwise the motor will wear and be used to what it began with.

-Pat

 

Alright man, thanks! My buddy ran the Rotella Synthetic 5w40 in his '89 XJ with no problems, but his also has 260K miles on it and had low oil pressure. I should have just stayed with what was in it instead of trying out new oil. I'll go get some 10w30 conventional.

 

switching to a "thicker" oil on a high milage engine is ok...nothing wrong with that...however i dont care what the bottle says on viscosity...SYNTHETIC is a THIN oil...Specially AMSOIL..my dad runs it in all his vehicles and it looks like water when he poors it in....NOT SAYING IT IS BAD OIL....dont want whowey to come along and get P*st. However i also THink Valvoline is thin compared to its same weight in penzoil. Take the synthetic out and put regular back in it.

Just a SIMPLE good brand oil will do for the old pushrod engines..i knew a girl back in HS that had a old crown vic with a 351 in it that had almost 300k on it...her dad bought it new and used conv penzoil in it from new.......

 

Don't want to start an oil thread but here's an interesting read. Even the auto mfg's are going thinner. Flow = lubrication, not high pressure. As the good doctor says, the 1st number (ie., 0W, 5W, 10WXX) is more important than the 2nd number.

http://www.supramania.com/aehaas/

 

btw, I run mobil 1 full synthetic 10w30. I use a mopar filter....I WILL NOT run any filter but a mopar on a high output, because the backflow preventer (i.e. check valve) is the best on the market and will keep the oil up in the valve train upon shutdown.


my engine has 8,000 on it, I put it in the truck at 3,000. it's a mopar reman and the P.O. couldn't afford to keep the jeep or the motor, so I stripped the xj down to build this MJ.

 

Thanks, it makes sense because when I first put the synthetic in it sounded like the jeep was a bit noisier. I thought I could've just been hearing things. I was hesitant on putting in the synthetic because I knew it was thinner, but my friend with the '89 assured me that since it was 5w40 it was thicker than running 10w30 synthetic so it should be fine. Guess I learned that you shouldn't listen to everything you are told.

Thanks for all the help guys, and I agree with running the mopar filter.

 

5W40 is not thinner.......it's thicker than 10w30 at normal operating temp. Did you read Motor Oil 101 in the link I posted above?