Where's the oil going?

With or without catalytic converter?

And yet...

Could easily be a pressure leak that doesn't show up until you're on the highway, at which point the oil leak takes a path that leaves minimal or no stains on the vehicle itself. One of the prime suspects for this kind of leak is the oil pressure sender. They can even still work as they leak under pressure. Other common leak points include the oil filter mount and others which I'm sure Steve L will comment on in greater detail eventually.

-Stern

Then it's quite possible the engine *is* burning oil. The catcon will consume and "invisible-ize" a great deal of oilsmoke so you'll never see it. Go do a cylinder leakdown test on all 8 cylinders.

-Stern

Probably a good idea to check the PCV system real well too. If that's it, the solution is likely very simple and cheap (replace or clean hoses and PCV valve).

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Or simply drop the cat and start the engine. It WILL be noisy, but a heavy oil burner will make visible smoke with the cat out of the way.

My '88 New yorker was using a fair quantity of oil, and showing NO smoke. I pulled the crossover pipe, and when I started the engine there were huge billows of blue smoke. Valve guides were very sloppy. Cat was also dead and had to be replaced to pass E-Test.

Ooo! Be careful. Unhitching the exhaust under the hood has caused many a fire, one I've seen myself.

--Geoff

You don't need to run it long enough to even get anything hot. Bad valve guides allow oil to run down into the cyl when the engine is shut off, and that oil makes a cloud of blue smoke immediately on startup.

Changed the plugs, cap, rotor and PCV. 2 of the plugs were a bit furry with deposits, but I've sen worse. Found a small leak at the rear main $eal. I think I'm burning some and leaking some. The rear main is too expensive to tackle on a van with this many miles. As long as the oil consumption doesn't get worse, I'll keep adding oil. Anyone here selling a low mileage, cream puff, Ram Wagon? -cadjak

At a quart per 400 miles? Yick. Why not just swap in a good used low-miles engine? It's sure to improve your fuel economy as well as your oil economy.

-Stern