On a 4x4, you can drop the pan without lifting the engine.

 

After finishing all the work, ran it again for another ~600 miles and lost almost the exact same amount of oil. I'm actually amazed at how repeatable it was. 5 quarts in, 3.75 quarts out, 1.25 quarts difference. Exactly the same.


Any other ideas for next steps? I really would rather not have to fill up 1.25 quarts of oil every 600 miles of driving. compression and leakdown to see if the rings are bad maybe?

edit: assuming it is the rings and I need a rebuild, what am I going to be looking at for a rebuild if I don't want to deal with it myself?

The other confusing thing is: I never blow smoke out of the exhaust. There is no way I am leaking that much oil either, I don't even see drops on the ground.

 

Mine is the same way. But, I go thru even more oil than you do. No smoke out the exhaust, no puddles on the ground..... oil just disappears.

Paying for a rebuild is gonna be expensive...... be better off just having someone drop a long block in. Used motor would be even cheaper... but, you might find yourself in the same position you are in now. Lookin' at a couple thousand no matter which way you slice it.

 

Back in the day, when I was primarily running Chevy 305s and 350s they were guaranteed to start using oil at around 100k miles. Both were spec'd for 10/40 oil and going to 20/50 would usually get you through without having to add between 3000 mile changes...

 

I don't get it.. I am trying some glow in the dark oil dye now and will post back soon. If I don't see it coming out of the exhaust or leaking from somewhere I am probably going to flip my lid.

edit: let's at least figure this **** out because its happening to both of our trucks and we can't explain it.

 

Did you have one that drank like mine did? If it was a quart over 3000 miles it would be one thing but doing about 6X that. 6X. quart every 500 miles just about. That is madness.

 

Yeah, those 70s Chevy small blocks were known for getting bad about blow by after 100,000 miles. Pretty much all those late 60s designed V8s were. Since the LA318, 340 and 360 were basically designed during that period, I guess using a good bit of oil with age is not too uncommon. Although a quart every 600 miles would be extreme with no smoke, no signs of a leak.

I can recall having a '71 Nova 305 that would drop a quart every thousand miles or so. Thicker oil and a Lucas product got it down to losing about half a quart every 1500 miles. Didn't have it long enough to tear it down. I had it one summer, sold it, drove my J20 4x4 all winter and bought a '73 Nova 350 SS the following spring. That one didn't lose more than half a quart in 3000 miles but only had around 70k on it when I bought it.

Have you rechecked the throttle body? If it's still getting oil in there your problem may be that you didn't torque everything down right in your Hughes install. That would account for it.

 

I suspect a compression test will tell the tale......

 

Interesting . . . I've seen some products like the Lucas products and even some that claim to be specifically to reduce ring blow-by and I've never been sure what to think. You never know with mechanic-in-a-can stuff right? However changing to 20W50 and seeing if anything changes would be interesting. I live in San Diego so the cold weather aspect shouldn't be much of an issue.

And it's true, I may have screwed up the plenum gasket, but god damn I was **** about torquing the gasket to spec. Inch pound torque wrench brand new so not out of calibration and I followed the sequence to the T.

 

I hope so. I can rent a compression tester from a local parts store yeah? This may be my next step in this investigation.

Oil dye is also in so maybe that will turn something up.. I was hoping I would see some orange glow in the dark coming out of the exhaust but nothing's turned up yet.