project88mj Posted May 10, 2007 Share Posted May 10, 2007 what kind is the 4.0 made to take? Link to comment Share on other sites More sharing options...
project88mj Posted May 10, 2007 Author Share Posted May 10, 2007 c'mon guys i need the help? Link to comment Share on other sites More sharing options...
comancheman Posted May 10, 2007 Share Posted May 10, 2007 i always run 10-30 6 qts for the 4.0 Link to comment Share on other sites More sharing options...
offroader461 Posted May 10, 2007 Share Posted May 10, 2007 i run 10W-30 valvoline Link to comment Share on other sites More sharing options...
DirtyComanche Posted May 10, 2007 Share Posted May 10, 2007 10w30 is probably the best option. But it varies by climate, intended use and engine age. But I'm not an oil guy. Link to comment Share on other sites More sharing options...
Oizarod115 Posted May 11, 2007 Share Posted May 11, 2007 10w30 in mine, brother runs UP TO 20w50 in his to get his oil pressure to rise a little bit (really bad oil pressure.) Link to comment Share on other sites More sharing options...
project88mj Posted May 26, 2007 Author Share Posted May 26, 2007 well i got 213K on the motor and do alot of higher rpms (3,500+) will 10w-30 work fine or synthetic? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 26, 2007 Share Posted May 26, 2007 10-30 high mile synthetic Link to comment Share on other sites More sharing options...
project88mj Posted May 26, 2007 Author Share Posted May 26, 2007 could you tell how will it help ? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 26, 2007 Share Posted May 26, 2007 no clue, it's in the chemical makeup...it doesn't break down as fast and helps to reduce anymore buildup of gunk in the engine, and clean it too i believe. Link to comment Share on other sites More sharing options...
Pete M Posted May 26, 2007 Share Posted May 26, 2007 Or you can just use any ol' 10W30 oil and change the oil regularly. :D Don't skimp on the filter though. Buy a good quality filter (meaning don't buy the cheap ones or a Fram). Link to comment Share on other sites More sharing options...
Eagle Posted May 26, 2007 Share Posted May 26, 2007 what kind is the 4.0 made to take? The old ones were supposed to use 10W30 or 10W40 (both were listed in the FSM). The newer ones are supposed to use 5W30 well i got 213K on the motor and do alot of higher rpms (3,500+)will 10w-30 work fine or synthetic? How's your oil pressure? If you're getting 40 psi or better at highway speed with the 10W30, it's okay. Personally, on a high mileage engine I would be using 10W40 or a wider range synthetic. In my '88 XJ I'm at 265,000 miles and I run Castrol 5W50 in the winter, 20W50 in the summer. And you shouldn't be running a 4.0L above 3,500 RPM a lot. Especially not an '88. The torque peak is WELL below that. You're just beating up the engine for no purpose. I doubt that mine ever goes above 3,500 RPM. My normal shift point is 2,200 RPM. Link to comment Share on other sites More sharing options...
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