4.0L Mileage/Life

250K miles is not unusual. Mine's at 137K miles and it still runs great and burns no oil.

Jerry

>

Hey Omar,

I got 27K miles out of my '01 XJ before a new short block was installed. I got to 29.9K before the head was replaced for a crack. Of course I was using Mobil 1 synthetic and AC oil filters. I got to 3years 2 days(30.1K miles) before the A./C evap was replaced. Dealer covered parts under warranty, but charged warranty labor rate($393 total)

Of course your mileage may vary.

Luck, Brian

Omar (RCN) did pass the time by typing:

Depends in great measure on how it is treated.

Change the oil every 3000-4000 miles it will last till the timing chain service is due at about 200,000 miles. Even then if it's not burning oil that's all that needs to be done. I'd expect lifters would need replacing sometime around then also.

Neglect it and your looking at much much less.

Mine was replaced at about 50,000 miles because the dealer neglected to put the radiator hose clamp on and it overheated badly on the highway. That cascaded to a failed rear main bearing and.. poof! dead engine.

The replacement block has spent over 50,000 miles under a blower and apart from an annoying rough idle bug, pulls strong.

Omar (RCN) proclaimed:

With reasonable care, 200 to 300K miles or more. Is a fairly rugged engine and has a nice built in over-rev warning that jars all of your fillings out at much over 3500 rpm.

My 91 YJ 4.0L just turned 243K miles and still runs very strong.

Are you implying that the use of synthetic oil (specifically Mobile 1), and AC Filters were the cause of your engine failures?

Campbell Freeman

Maybe he put the Mobil 1 in his radiator instead of the crankcase. ;)

I took it to mean that even with the added > Are you implying that the use of synthetic oil (specifically Mobile 1), and

Campbell,

No, I still use synthetics and AC filters, but I believe the root cause for engine failure was a defect in the head. Only after I made the dealer add coolant when the bottle was empty(3X in 3 weeks) did they actually believe me. I had to force documentation to get somewhere while still under warranty.

Brian

Mine has 170,000 km and I expect to get that again with no trouble. Just do the recommended services and make sure you change all of the radiator and cooling hoses at about 120,000 km, and you should have no problems up to at least 300,000 km (that's km, not miles) That applies to most engines, actually.

-- GW De Lacey

Yes I believe it is. The thing I like most about it is the low down grunt, like a diesel in some ways. It performs very well on the highway into the bargain, unlike almost any diesel I've ever seen.

In other words, the 4.0 has all of the characteristics I need in a power plant for an off-road vehicle. On top of all that, the fuel economy is almost as good that obtained on almost any "equivalent" screaming V6.

A great engine, as old as Methuselah, but has yet to be bettered.

-- GW