Thicker oil

OK, does the 4.0L HO like a heaver oil?
For the past 20,000 miles I have been running Mobil 1 10/40. Mobil 1 filter as well.
No problems at all with that. The XJ is a 98 with 88,000 miles on it.
Is this oil adequate for this motor at this mileage?
I am taking it on a trip next weekend from NY to VA Beach. I plan on changing the oil before I go. Would a heavier oil offer better protection on a long 9 hour trip, or is the mobil 1 10/40 going to be OK for this?

Just looking for any thoughts about this.

Thanks everyone.

The mobil-1 10w is fine. My 98 is has around 270,000 mi and has been happy with it, the filter I use is also a mobil-1 or a K&N...

I tried 20-50 once and it put the oil pressure way up there. I went back to 10-30.
BSD

Use 20w50 or 20w40 at temps above 30, 10w30 or 10w40 above 0 and 5w30 below 60. Temperatures are in F, this is from page 90 of my owners manual. I run 10w30 year round in Iowa where the temps probably range similar to new york, -20 to 105. If your oil pressure at warm up seems low or you drive severe temps for long periods of time then go with the 10w40.

I run Castrol GTX 20/50 year round here in north Texas. 123,000 miles and going strong. 50 lbs pressure at 65/70 mph.

bustednutz said:

OK, does the 4.0L HO like a heaver oil?

Click to expand...

That depends on whether the bearing clearances are high enough to cause a low oil pressure. If so, a thicker oil (15 or 20W-50) will keep the oil pressure up and the engine can last a bit longer before it needs to be rebuilt. Otherwise, run the manufacturer's recommended 10W-30 unless the weather's extremely cold (less than 32*F, use OW or 5W) or extremely hot (more than 100*F, use 15W-40 or 50).

When I bought my '88 the recommended oils were 10W30 or 10W40. For the newer ones they recommend 5W30, but that's mostly for fuel economy. For a 4.0L with less than 100,000 miles 10W40 is an excellent choice. It's what I ran in the '88 for the first 175,000 miles of its life -- then I switched to synthetic and I now run Castrol 5W50.

The deciding factor should be your oil pressure. If it's between 40 and 55 at highway speeds you're in good shape.

i run luas oil booster in everything!i had TOTAL oil loss in 460 ford twice and engin is still ok.