FYI Redline oil rocks at 168K on 92 XJ!!!

H

Heinz

NAXJA Forum User
Hey guys, just had to say this - I swapped to Redline full synth. a few mos. ago. Changed filter from Fram to a good Mobile 1 at 3-4K and added another qt. of 10/40. Drive the crap outta my 4.0(80 mph in 100 degree plus temps) and at 168K plus it doesn't loose a DROP! Pressure stays constant at 40+ lbs while cruising and HOT, drops to 25-30 and back up when oil cools. Wow worth the $6 a quart! I figure is good for 7-10K before change, although it is dark looking?
 
Doesn't the 4.0 take 10-30W?
 
Technically yes, but from reading on here, and other places, 10w40 is said to be the better choice, but will depend on where you live as well. I'm using 20w50 for the summer and find it works better for me. Will switch it to 10w40 for the winter.
 
I never liked the lower oil press. of 10/30, the 4.0 runs hot and seems to like 10/40 better - if I know I'm gonna be running in hot weather lots, I'll even run 20/50.
 
I never use anything higher than what is recommended in my cars or my customers...Thicker oil is only necessary to raise oil pressure to the desired level on a well worn motor. Not sure how hot it is there...but here in So' Cal. it regularly gets over 100.

My wifes XJ (94 4.0) has 180K and uses 5w30...doesn't leak and doesn't burn it. 60 lbs of pressure at hot cruise.

Mine (97 4.0) has 140K on it and is about 45 lbs at hot cruise with the 5w-30.

Thicker oil than necessary will also lower your mileage slightly.
 
And if you're fortunate enough to own a newer XJ I believe using anything but 10W-30 can void the warranty.
 
I use mobil 1 synth. with Napa(wix) gold filter. Change every 5K. Never used one drop, even with a slight leak! It is usually dark by 5K though. 205K on engine now, and I swear it runs better than a new GC.
 
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