jeepxj07

I have a 94 xj and it burned a little bit of oil when I bought it but now it does it sometimes. When its cold outside it doesn't burn oil and even when its hot sometimes I crank it up and it doesn't burn oil at all but sometimes its burns A LOT, like will fill the air with blue smoke... any advice?

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tjwalker

Details needed.

*How many miles on this engine??
* Exactly HOW MUCH oil during an oil change period (say 3k) does this engine burn?

1. Ensure the CCV (crankcase ventilation system) is working properly. That is the system of tubes and grommets leading in and out of the valve cover. New hardware is only about $45 to rejuvenate the CCV system

2. Run a compression test. It is by far, the best "snapshot in time" of the internal condition of the engine. Spec compression for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders. Run the test both dry and wet to determine if you have a problem with the lower end or the valvetrain.

jeepxj07

I have 174,000 miles on the engine and I don't know exactly how much it burns because I leek oil from my rear main seal and from my oil drain plug but driving it 4 or 5 times a week I have to add about a little more than a quart once ever 3 weeks.

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89Laredo

Thats alot of oil..
I would say bad rings. How long have you had it? Im guessing the PO didnt take very good care of it.

tjwalker

Compression test still the best way to get more information on the condition of your engine.

DaddyCat

Most of the time the rear main seal gets blamed for leaks that are really caused be failed o-rings at the oil filter adaptor. They are pretty easy to replace and only about $6 for the o-ring kit from the dealer.