'03 Liberty with code P0420. And low engine oil level!

TeeJay00 · 05-08-2012, 04:02 PM

My '03 recently triggered this code P0420 "Catalyst System Efficiency Below Threshold (Bank 1)".

When I searched this forum someone mentioned something about the engine consuming oil. Which could trigger this code. Not sure if this the case in my Jeep but I've noticed that after several thousand kilometers the engine oil level gets very low. Yesterday I added three Liters of oil after using the car for about 4000 kilometers. I am using 5W-40 synthetic engine oil. I don't have any leaks in the engine and there is no smoke suggesting a bad piston ring or so. Shouldn't there be a light in the dash for low oil level?

Should I deal with this as one? Or two different issues?

Note that the engine oil thing was happening for about a year now. Never had the time to look into it. I've always checked the oil level and just keep adding oil till the next change.

tjkj2002 · 05-08-2012, 05:13 PM

Ever change the PCV valve? A bad PCV valve can cause oil to be used.

TeeJay00 · 05-08-2012, 05:42 PM

Quote:

Originally Posted by tjkj2002

Ever change the PCV valve? A bad PCV valve can cause oil to be used.

Interesting... Since it's a cheap fix I'll try that. But are those two problems related?

TeeJay00 · 05-09-2012, 05:21 AM

Just took it to a mechanic. He said that since the oil level decreased that can only mean that the engine is burning oil

socks · 05-09-2012, 06:02 AM

I'd get a second opinion if I were you.
Some mechanics will say anything to generate a work order.
We brought our KJ in for a free oil change at the local Chrysler dealership and a Chrysler mechanic
told us that we needed a new front driveshaft because all the components were worn out...
This is after we had a custom made driveshaft built up using "U" joints!

What was it?

Just prior to bringing in our Rig for the oil change I loosened the drivers side swaybar end link at the
lower control arm just enough to make a clunking sound to see just how crooked this stealership was!

Like I said, get a second opinion.

TeeJay00 · 05-09-2012, 07:30 AM

Yeah I've had my share of stealership incidents

which is why I prefer doing as much work myself on my cars as I can.

Anyway. I got all three crankcase breather valves today. Will install them tonight and I hope this will solve my oil issue.

And by the way, the check engine light turned off by itself this morning and till now it's still off.