Oil weight and filter recommendation

Atlwheeler32

New member
I just purchased a '94 4.0 with 147K. I changed the oil and now, at idle, it sounds like the Jeep has a diesel engine. I've read many differing opinions on what it could be - either a lifter issue, a cracked exhaust manifold, or a normal sound for an old Jeep.


I did not hear the noise until after I changed the oil. I was in a rush and was forced to use a Fram filter from W-mart. I have heard that this could be the cause of the sound. My first thought is to change the oil and filter. Any recommendations on oil weight and filter brand for an 18 year old vehicle with 147K miles?
 

WIX oil filter and Valvoline VR1 10w30 (w/ZDDP)
 
JPninpa, At first I didnt understand why you would recomend a oil for flat tappet cams used in the sixties and early seventies cars that need a high content of zink (zddp). most modern cars use full hydrolic or roller assemblies nowa days, and the VR1 is a racing oil (due to the high ZDDP rating) and is expensive, not as bad as the sythetics though. I have to run it in mine to avoid wiping my cam lobes on my flat tappet cam. That being said and thinking about it, I would use it as well. The high zink helps protect the wear on metal parts in the engine. most oils made today do not have this high content of zink like the oils of yesterday, and aparently dont protect as well. I think this would be the best oil you could run and see if it quiets things down a bit. I guess its like the gas of today vs the high octane gas of back in the day.
 
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There are zinc additives, also high mileage oils and diesel-spec oils have more zinc.
Most diesel-spec oils are 15w-40 but Wal-Mart has Rotella T-5 syn blend that is 10w-30. I used it once in the Jeep and oil consumption was higher with it but the Used Oil Analysis was fine.
Now I use Valvoline Max Life 10w-30 and a Purolator PureONE filter. The textured can is easier for me to tighten since my left arm isn't working at 100% yet after rotator cuff surgery last year.
Either diesel-spec oil or the high-mileage oil of your choice would be fine. Purolator PureONE, OE Mopar, Wix, NAPA Gold, are all good filters. Mobil 1 or K&N filters if you want to spend a lot of money.

Our Jeep got quieter after I had the header put on. One exhaust manifold bolt was loose and another was missing. So check all those.
 
69jeepcj
Well the ZDDP is important for my vehicle as there are many issues noted with ware out of the cam and oil drive gear....
 
yeah, I know and agree with you. My mind just automaticly went to thinking of the muscle cars for a minute, and wondered why in a new car. Then realized for the same reasons basicly.
 

They lessened the zinc (ZDDP) level in oil because it would contaminate the cats in cars that burn oil. That said, with roller lifters you don't need as much anyway. Diesels don't have the same type of cats, if any at all, and need the zinc so diesel oils still have it. Another thing, if you look at the starburst on the back of a bottle of oil, regular oil will say "Energy Conserving". Most high-mileage oils will not say that, meaning that they are better for flat tappet engines.
 
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