427 FE sideoiler - Oil Consumption

[twobjshelbys]

There is a huge difference between leaking oil and burning oil. Sounds like you're consuming it. The pcv path is one. The others are not good news.

Note 1: Q: how do you tell a side oiler is out of oil?
A: It stops leaking

[767Jockey]

You might have a possible intake manifold leak as well, that's a somewhat common issue in the FE. If the PCV investigation yields no results, pull your spark plugs, see if any are oil soaked or discolored. That'll start you down the trail of learning where the oil is entering your combustion chamber(s). You'll need to start tearing into the engine to learn where the pil is entering the chamber to be burned. First step is pulling the intake and look for telltale signs of intake gasket failures and/or a poorly machined and fitting intake. If you find you have "Print - O - Seal intake gaskets, you may have found your issue right there. Good luck.

[patrickt]

But as an interesting point that you rarely hear discussed, the oil consumption in my big beautiful FE is not consistent from the FULL mark down to the ADD mark. My consumption for the first half quart is noticeably faster than it is for the second half quart. In fact, my consumption trails off dramatically when the oil level hits around the half way down mark.

[Grubby]

I was a Product Engineer at GMC Truck in the mid-90s. At that time 1 quart per thousand miles was consider acceptable.

It was rare. Most didn't use enough to need oil between changes.

John

[Bobcat]

MD427 , yes ..... removing the PCV can increase crankcase pressures . Answer is simple ... a breather in the VC on each bank will let in enough air for that to not be a problem .
I tend to agree with others that the PCV is where I would start since this ( if I read your posts correctly ) just started right after an oil change and wasn`t building up over a time period .
I had to play around with a bunch of different PCV valves before I found the right one .
Pull a few plugs , with that much oil usage , they should be covered with oil .
The PVC check is the easiest one of the solutions to try first . I would tend to write off the VBC baffling as the problem just started and I`m guessing the VC`s have been on the engine for a while .

[MD427]

Originally Posted by Bobcat

MD427 , yes ..... removing the PCV can increase crankcase pressures . Answer is simple ... a breather in the VC on each bank will let in enough air for that to not be a problem .
I tend to agree with others that the PCV is where I would start since this ( if I read your posts correctly ) just started right after an oil change and wasn`t building up over a time period .
I had to play around with a bunch of different PCV valves before I found the right one .
Pull a few plugs , with that much oil usage , they should be covered with oil .
The PVC check is the easiest one of the solutions to try first . I would tend to write off the VBC baffling as the problem just started and I`m guessing the VC`s have been on the engine for a while .

To be clear we don't really know how long this has been happening. As said earlier, I've put 300 miles on the car in 6 months. But I bet the motor doesn't have a combined 300 miles on it in the 15 years prior to that. And an outside mechanic was doing the annual maintenance, and oil changes. It's possible that it has been like this for a very long time and we just didn't notice due to how infrequently it was being driven.