2004 wj 4.0 oil question

P

Pak713

Joined
Jan 30, 2022
Messages
4
Hey everyone. I’ve owned this 04 wj for about a year now and I’ve only had to change the oil twice so far. It’s my daily in the winter then kinda a trail back road rig in the summer as we leave it at our cabin. I’ve been running 10w30 rotella t4 and wix filter since I’ve owned it. It’s pretty noisy. I know they are noisy engines but after changing the oil today upon start up it sounded louder with clean oil now lol. I let it warm up and it sounded a little louder than it normally does when warm. I run the t4 year round and I’m in Michigan. The jeep runs good but noisy. My noise doesn’t clear up after it’s warmed up. It usually will subside a tad when warm. The jeep has 183k on it. Wondering if I should be looking at running something else to combat the noise and maybe quiet it down a touch? Honestly this has to be the noisiest engine I’ve ever owned.

When I got it we put a lot of work into it since it had been sitting for a couple years. I had the pan off and everything looked good. Didn’t see anything out of the ordinary. I also had the valve cover off and changed the gasket and had no collapsed lifters or anything like that. If I had to guess the noise is mid engine so it probably is a lifter. Definitely louder from under the jeep. Well any suggestions are appreciated! Thank you.
 
beyond a mechanical repair, assuming that is where the noise is coming from, I suggest running a 5w40 or 5w50 oil in the old 4.0. There are two things that kill the engine, 1 is overheating, and the other is neglecting the oil change. Yoy could try a flush, perhaps with 1 quart of ATF, and a few short oil changes to rule oil oil flow, but other than that, it must be mechanical
 
ripcord said:
The ATF thing is a relic of the past. Modern motor oil has more detergents than ATF.
Click to expand...
funny thing, recently i had a blow by issue with my 91 4.0 YJ, flushed with 2 quarts ATF, 4 quarts valvoline white bottle, twice, after about 1000miles of driving, and valve came unstuck. I am sure the detergents are better these days, but there is still value in the ATF flush thing I think. Same reason ATF and acetone is a great penetrant, and ATF is a great cleaner for guns, where as motor oil not so much. Interesting, thanks
 
weaponoffreedom said:
funny thing, recently i had a blow by issue with my 91 4.0 YJ, flushed with 2 quarts ATF, 4 quarts valvoline white bottle, twice, after about 1000miles of driving, and valve came unstuck.
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I'm confused by your use of terminology. Blow-by is caused by combustion gasses getting by the rings, typically due to wear or ring sticking. What "valve" are you referencing here that became "unstuck"?
weaponoffreedom said:
I am sure the detergents are better these days, but there is still value in the ATF flush thing I think. Same reason ATF and acetone is a great penetrant, and ATF is a great cleaner for guns, where as motor oil not so much. Interesting, thanks
Click to expand...
"Back in the day", ATF was made with sperm whale oil, which is an ester, and would clean. Simultaneously, oils were not well formulated to keep things clean. This is where the reputation for ATF being able to clean came from.

Modern ATF's are blended using the same base stocks we find in engine oils. They are typically light, around an xW-20 equivalent in viscosity. They do not contain esters, AN's or any solvents that would facilitate cleaning, of course neither do your typical engine oils. What engine oils do contain are detergents and dispersants (so do ATF's, but in lower quantities due to not having to deal with combustion byproducts) which are there to prevent deposits from forming, not clean up existing ones.
 
Chris142 said:
If it's mid engine and ticking @ 1/2 engine speed it's the oil pump drive assembly. I've put 3-4 in my 2002 over the years. It's a 5 minute job.
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I'm going to get my auto mechanics stethoscope (a long screw driver) out when I get home and have a listen to my daughter's Cherokee. Thanks for the tip!
 
OVERKILL said:
I'm confused by your use of terminology. Blow-by is caused by combustion gasses getting by the rings, typically due to wear or ring sticking. What "valve" are you referencing here that became "unstuck"?

"Back in the day", ATF was made with sperm whale oil, which is an ester, and would clean. Simultaneously, oils were not well formulated to keep things clean. This is where the reputation for ATF being able to clean came from.

Modern ATF's are blended using the same base stocks we find in engine oils. They are typically light, around an xW-20 equivalent in viscosity. They do not contain esters, AN's or any solvents that would facilitate cleaning, of course neither do your typical engine oils. What engine oils do contain are detergents and dispersants (so do ATF's, but in lower quantities due to not having to deal with combustion byproducts) which are there to prevent deposits from forming, not clean up existing ones.
Click to expand...
I am not going to argue with you,. clearly you know more about things than I do. I defer to your expertise.

Is a valve cover in a 4.0 jeep pressurized? no......but mine was about 1/2 psi or so.

Cylinder 6 compression valve was not seating all the way, 106psi on compression test, all others were 140 or so. Noticed oil on air filter. Did above mentioned service, blow by was gone, # 6 came up to 127. 291000 miles.

@Pak713 please do not take my suggestion, please listen to @OVERKILL and @kschachn
 
weaponoffreedom said:
I am not going to argue with you,. clearly you know more about things than I do. I defer to your expertise.

Is a valve cover in a 4.0 jeep pressurized? no......but mine was about 1/2 psi or so.
Click to expand...
So the PCV valve was stuck?
weaponoffreedom said:
Cylinder 6 compression valve was not seating all the way, 106psi on compression test, all others were 140 or so. Noticed oil on air filter. Did above mentioned service, blow by was gone, # 6 came up to 127. 291000 miles.
Click to expand...
There isn't a compression valve ;) Do you mean intake valve? Like it was leaking compression back up the intake? If not, it sounds like you might have stuck rings on #6. Would probably benefit from a piston soak.
weaponoffreedom said:
@Pak713 please do not take my suggestion, please listen to @OVERKILL and @kschachn
Click to expand...
 
OVERKILL said:
So the PCV valve was stuck?

There isn't a compression valve ;) Do you mean intake valve? Like it was leaking compression back up the intake? If not, it sounds like you might have stuck rings on #6. Would probably benefit from a piston soak.
Click to expand...
There is no pcv "valve"

Yes excuse me, intake valve, on the compression stroke, worded it wrong, either way, it solved the issue. ATF flush.

Stuck rings on 6 does not create pressure in the valve cover, a non seating valve would.

Yep soaked in ATF did the trick.
 
weaponoffreedom said:
There is no pcv "valve"

Yes excuse me, intake valve, on the compression stroke, worded it wrong, either way, it solved the issue. ATF flush.

Stuck rings on 6 does not create pressure in the valve cover, a non seating valve would.

Yep soaked in ATF did the trick.
Click to expand...
Probably because it was soaked in a clean hydrocarbon of any sort.
 
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