My engine has about 30K miles. It runs well but has always had a huge oil appetite. I did an oil test on oil that has been about 5,000 miles. During that time I suppose I have added 15 quarts. I gave up on such niceties as Mobil 1. Such is life.

I will also say that during this 5K run I have had two transmission problems and both times I ran for about 120 miles (each time) at about 3800-4000 RPMs to get it where it needed to be. I have no idea if that makes any difference.

Blackstone notes an increase in copper and lead and say it is probably coming from bearings.

My question is, should I venture out on a 4500 mile round trip?

Here is the report: http://graestone.org/GMC/2015_Oil_Test.pdf

Advice, please.

...Is your dip stick callibrated? You may have the slight overfill problem where the top quart keeps burning off and you keep adding it back in a vicious loop. ...

Is the trans problem fixed? Could be pinched or cracked or porous vac line to modulator. If you were in 2 nd gear you would use more oil as more revolutions per mile. Costs about $1 to fix vac hoses. Are there any oil leaks?? Signs of smoke? Is your dip stick callibrated? You may have the slight overfill problem where the top quart keeps burning off and you keep adding it back in a vicious loop. You can tell a lot about the health (tolerences) of an engine by just listening to it and gently running it through the rev range cold and then hot. My take is if you hear no bearing knocks the engine is probably ok. Normal oil pressure readings would help to reinforce this guess. You could be sucking some oil due to a slight gasket mal alignment on the inside face of the intake. Pulling plugs may point to where, as may vacuum readings. You can pull the intake and reseal in a few hours at low cost if diagnosis suggests. I would change my oil and filter before 3000 mile marks as this is like 6000 miles if the Olds was in a Toronado in terms of pounds of fuel consumed. This in light of the unfolding research on the amount of oil the Olds may be filter bypassing with more to come on this mystery.

JohnL455 wrote on Sun, 09 August 2015 10:36

...Is your dip stick callibrated? You may have the slight overfill problem where the top quart keeps burning off and you keep adding it back in a vicious loop. ...

Good question.

More importantly though, the lead and copper readings would have been quite a bit higher if the sample had been oil that had run 3000 miles, rather than a mix of fresh oil and oil that has been in it for a few thousand miles (he says he has added about 15 quarts in 5000 miles).

.

Try to pry the crank back and forth it shouldn't move more then around ten thousanths. If it moves much more the thrust surface in the center main bearing is going south.

roy1 wrote on Sun, 09 August 2015 21:14

Try to pry the crank back and forth it shouldn't move more then around ten thousanths. If it moves much more the thrust surface in the center main bearing is going south.

I had wondered about that end-play issue. I think I know how to pry forward but how about backward? I don't want to put pressure on any delicate parts/

George,
Last summer on the way to a rally, a rocker retainter broke and allowed the rocker to fall off of the "T" pedestal. (Cadillac 500) The pushrod then popped out, followed by the lifter popping out of its bore. I heard the noise and looked down in time to see the oil pressure drop to zero. I was in a round-about at the moment, so had to drive through it. Shut down and had the coach hauled home. I replaced the stock rocker system with a shaft type system, put in a new lifter and pushrod, changed the oil and started. No noises and good oil pressure. I then drove it to Florida and back. (4500mi). Upon return, I did an oil change and sent a sample to Blackstone. Sample showed a tripling of ppm in Iron, Copper, and Aluminum. I then drove it another 2010 miles and sent in another sample to find that I had relatively the same amount (maybe a little more) of those metals in the changed oil. The Copper numbers bother me more than anything because it means that somewhere in there (rods, mains or thrust) things are worn down into that layer.Clearly there is something going on in there, something that happened after the rocker failure and loss of oil pressure. So.....not wanting to get stuck in tim-buck-two with a rod or main out, I have decided to pull the engine and replace it. FYI, here are the #'s

4500mi oil change
Copper 110ppm
Iron 68 ppm

2010 oil change
Copper 74ppm
Iron 31 ppm

Universal average for Copper is 47ppm but my engine has been running in the low 30's ppm until the rocker failure.
Universal average for Iron is 44ppm but my engine has been running in the low 20's ppm until the rocker failure.

Hope this helps you with your decision.

I think the flaw in the logic is that you should discount all the added dilution oil in the figuring. Though the oil is going somewhere, I would venture the contaminants are remaining in the engine, especially any metals continuing to increase in concentration. From a calculation standpoint that means your engine is 'less bad'. I'm lucky as my Cinnabar 455 has some fairly loose pistons as you hear piston rap at cold start but driving Chicago- Phoenix-Chicago I added 1 quart the last day of the trip running 5w-40 Blue jug Rotella T6 full synthetic. Can't complain or piston fit has little to do with ring fit?

I think I am just going to drive the thing and hope for the best. I may do a sample again after 1900 miles. That will get us to our friends Randy and Margie's in MO. They left their coach in CA last winder so I guess it wouldn't be too bad to leave ours in MO if it was down. Hmm, I am thinking Randy would not want his coach out in the elements so mine could be in the cozy barn... for the winter. Ha.