15W-40 in a Jeep

[99]

quote:

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Originally posted by Gary Allan:
The 4.0 must be THE noisiest engine on the planet at idle short of a diesel. Even with my mopar roller rockers you can hear the thing inside the house with its distinct volume/tone. Even at a 30% reduction in volume it would still be loud.

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Older 4.0s up to about 99 are noisier. After that they have quieted down a bit. I think DC used a thicker block or replaced the pistons with tighter ones. Not sure, but they did do something. I do know that "4.0 drone" you speak of though. I can tell a 4.0/Jeep is around by just hearing the engine run.

 

[adam123]

They are Very loud but from what I have experienced they are very reliable engines.

 

[Johnson110]

I put 8oz of seafom in my 4.0 161k with a 10w/30 oil change, hope the seafoam helps claen the motor,it always got oil changes at 3k since i brought it with 110k on it!