I have a 1990 xj with just under 200k miles. What would be the best oil to use. I was thinking the high mileage oil but I want the best possible fluids for this truck. Thank you for the help.

 

Fsm says 10w30 so I would use that thats the spec the engine was built to...high mileage oil is just a gimmick the just add more detergants and crap so theres actually less oil than additives

 

Ah thank you. Had no idea. So full synthetic or regular oil?

 

If you have been running regular, then stick with regular. If synthetic run either. the reason is because the seals will all start leaking quite baddly if you throw synthetic at it after running regular oil.

For the oil brand and filter, I personaly prefer Rotella 10w30 and a napa gold filter. I have been running this in my 98 fo 205k miles and it runs perfect.

 

Damn OK. Thank you. Well I have to replace the valve cover gasket so I'm guessing the gut I bought the jeep from was running synthetic, I picked up the Pennzoil platinum full synthetic and aa fram oil filter. I've been running that in my civic and love it. I also got some seafoam and will run that before I change my oil. Should I pour half the bottle into the oil and half into my gas? This truck has been sitting for a yr so she needs some tlc

 

Not trying to tell you what is good and bad but the fram filter is actually terribe. I even have seen them blow apart on the jeeps because of the higher oil pressures in the winter. If your on a budget go to walmart and grab a mopar filter for like $5, they are factory. but it is your vehicle so do whatever you feel.

 

conventional oil. 5w30 is what chrysler reccomends for our jeeps from factory. i use thicker 10w30 for better protction.

 

I run rotella T because it still has zinc in it

 

At 200k your fine with 10w30

Ron

 

Wow damn. OK ya I'm gonna go Ger a different oil filter. Had no idea! Thank you for that. Now as for the seafoam. How should I do it. Half in.the oil and half in the gas before my oil change?

 

I used it and had not luck. I had a friend use it in his 95, no luck. I had better luck with the lucas oil fuel cleaner

That said, it does not hurt to try. NO, for seafoam, use half in the brake booster line, and half in the fuel tank. I do not recomend the oil additives as they may cause more damage to the engine.

 

I actually had bad luck with rotella 10w30... It made my jeep sound like a diesel so i switched back to valvoline blend after 1,000 miles. Im not sure if its related but right after i switched back, my distributor went out.
I also think you shouldn't use seafoam in your engine... It caused my rear main seal to leak....
I've been using k&n oil filters and get them from amazon for a good price. Mopar filters are decent... Heard too much bad stuff about fram to use it again though nothing bad has happened to me when i did use it.

 

lol I highly doubt rotella made your engine sound like a diesel or that seafoam made your RMS leak

 

if you are due for an oil change, 1/3 of a can of seafoam in the crankcase would help clean things up a bit, just run it for a few hundred miles or so then change it.

 

Two strange coincidences i guess. But things sounded way better when i switched back. And the rms only started leaking after the seafoam... It was otherwise leak free. Just stating my experience. Lol.