Burning Oil and making black smoke from exhaust

My 2002 Jeep KJ is approx 135,000 miles and I've only had it the last 2,500 (since last Nov). I know the last owner changed the oil regularly with conv. but I don't know if it was overheated. It also doesn't leak- as far as dripping onto the ground or on the ******.


What's been done:

• New Rear lower control arms
• New Mopar PCV valve
• Mobil1 Full Synthetic Oil & filter

It burns an average of approx 1 quart per 200 miles. I'm thinking I'll need a compression test.

Are there any issues I might experience if I continue to DD this (I religiously check and refill the oil due to the consumption)? I already get 12-17 mpg babying it and the speed limits are 55 where I drive. I also let it get to operating temp, as well.

Thanks guys!

In for answers, I add about 1/2 qt. every 2 weeks to the wifes 02. I never see any smoke, no oil leaks and the plugs always look good. It has 140,000mi on it.

Spr said:

My 2002 Jeep KJ is approx 135,000 miles and I've only had it the last 2,500 (since last Nov). I know the last owner changed the oil regularly with conv. but I don't know if it was overheated. It also doesn't leak- as far as dripping onto the ground or on the ******.


What's been done:

• New Rear lower control arms
• New Mopar PCV valve
• Mobil1 Full Synthetic Oil & filter

It burns an average of approx 1 quart per 200 miles. I'm thinking I'll need a compression test.

Are there any issues I might experience if I continue to DD this (I religiously check and refill the oil due to the consumption)? I already get 12-17 mpg babying it and the speed limits are 55 where I drive. I also let it get to operating temp, as well.

Thanks guys!

Click to expand...

One quart every 200 miles is excessive fore sure
My 03 for example, with over 150,000 miles burns about 1/4-1/2 quart every 3500 -3700. I usually change the oil every 3000 miles or so so never worry about it
Plus its driven harder than most, it hits 85-90 a few miles every day going to work and several times bounces off the rev limiter taking off from stop signs etc
I drive 92-95 miles a day back and forth to work
So yes for sure have it checked, oil is either leaking or burning somewhere

Black smoke has me confused, as that is normally indicative of an over rich fuel mixture. No blue smoke?
It is time for a compression test on all 6 cylinders, and a leak down test.
Post the psi compression test results back here please.

From what you posted about your oil consumption Tom, I figured this was excessive. I'm about to get my truck checked since I think its flexplate is cracked and I don't have the tools to do it. So I'll see when I can afford the compression test (both time and money)... the oil consumption has been expensive since I've replaced the oil with the Mobil1 synthetic (5 qt jugs).

Yup, no blue smoke... just black like diesel. I try to drive like an old man to maintain the best mpg and physical condition of my vehicles. I wouldn't be able to drive like Tom, I'm too afraid to bounce off the rev limiter and potentially have the engine seize.
Especially when I don't have the money, tools, or know how to fix an engine or ******.

The worst part is that I started to really like this Jeep. Combine the oil cons. with rockers that went from solid in Nov. to a couple rusted holes this month... it's kinda sad.
I'll keep you guys in the loop. I really don't want to put much money in the Jeep now.

Here's a link to pics of the rockers: https://imgur.com/a/FPWbwL9