I have a Disco II, 149k miles, new driver side headgasket, valve stem seals, valve lapping, all new plugs wires and coils (I had to replace #7 exhaust valve, had a chip missing). Fresh oil change with Rotella 15-40, after a sea-foam oil flushing. No engine lights, runs fine, but will occasionally smoke out the exhaust, sometimes really heavily but never for very long, but frequently enough that I cant go for a SMOG check that needs to be completed for out-of-state transfer. Found oil traces on #7 and #4 plugs, but both cylinders have 185 psi during compression check.
​​
​​​​​My thoughts were possibly rings at first but wouldn't I get a lower compression reading? Kinda stumped at the moment and want some opinions or advice before deciding my next move. Will look for engine swap if I have too, just need to pass SMOG so I can let my sister use the truck.

Thanks in advance!

 

What color is the smoke? Are you positive its oil burning and not the truck running rich? Were the oil separators replaced when your valve covers were off?

See if you can get a scope in the cylinder and check the cylinder walls to see if there may be scoring that doesnt travel all the way up and down.

Also, was the valve work done by a reputable shop? Could it be a leaky valve seal? Just a few ideas to start with. If its definitely oil but you're holding compression, I'd guess valve seal.

 

I did all engine work myself. After some more digging and a little scoping, cylinder walls were fine, but I did find a missing oil separator on the driverside valve cover, and a very faint trail of oil inside throttle body points to that vacuum line. Made a makeshift oil separator until part can be ordered.

Even more digging, this time with an OBD-II scanner, revealed a dead Bank 2 Sensor 1 Oxygen Sensor. Readings were between 0 to 0.04 volts, whereas the opposite bank was fluctuating normally between its rich/lean cycles.
​​​
Appears to be running rich and only faintly burning oil when it makes its way up through the valve cover.

Glad it appears to not be rings or some other mechanical headache!

 

Great to hear! Odd there were no lights with a bad O2, but I guess that happens once in a while.

 

It's a head scratcher for sure, CEL bulb works as it lights up with all other indicator lights during first key on cycle.

 

The driver's side valve cover vent isn't suppose to contain an oil separator, if I remember correctly.

From RAVE pg. 161;
No mention of the LH side.

That being said, my throttle body was soaked in oil from that breather pipe, but I attribute that to my massive vacuum leak

 

i never got the CEL with bad o2 sensors on the front. Just pending codes. I replaced em with walker o2 sensors from rock auto n all is well now

 

Thanks for the info, I will have to check out this RAVE thingy many are referring too...
​​​​​​
If it passes smog I'm half tempted to just leave it in there, can't really do any harm could it?