Vortec 5.7l oil consumption.

[Supercharged111]

I have 180K on my 5.7 running 5w/30 and it does not use any oil. It does however have a rear main seal leak. I swithed from 10w/40 to 5w/30 because of an engine knock when cold.

0W30 or 0W40 would be even better for cold oil flow. I don't know why more people don't run those weights.

 

[DavidAlan]

My truck uses a synthetic bled and has over 367,000 miles on it, and doesn't use oil at all, when go thru a quart of oil, usually means your have some loose parts in your engine, some say it normal, but others suggest replacing or rebuilding the engine,will see if I can make a million miles before replacing engine.

 

[Nad_Yvalhosert]

0W30 or 0W40 would be even better for cold oil flow. I don't know why more people don't run those weights.

Because the "thinner than water" oil viscosity burns quicker and hastens oil consumption.

 

[Pinger]

0W30 or 0W40 would be even better for cold oil flow. I don't know why more people don't run those weights.

My objection to a big difference in the two numbers is that the difference is made up with viscosity improvers which will shear down in time, accelerated when there are gears. The actual oil viscosity can only be as thick as the W number permits - the rest is VIs.

Intuitively, it seems that actual oil between the moving parts is better than VIs.

 

[PlayingWithTBI]

Because the "thinner than water" oil viscosity burns quicker and hastens oil consumption.

I wonder why most German manufacturers (Mercedes, Porsche, VW , etc) recommend Mobil1 FS 0W-40? I've used it for years in my Crossfire, Infiniti Q45, Durango, C1500 truck, etc and haven't used/burned any oil in 7,000+ mile intervals. My Crossfire came from the factory recommending Mobil1 @ 7,500 miles changes, ha ha. Mobil1 ESP 0W-40 meets GM Service Fill Approval Dexos2.

 

[Nad_Yvalhosert]

I wonder why most German manufacturers (Mercedes, Porsche, VW , etc) recommend Mobil1 FS 0W-40? I've used it for years in my Crossfire, Infiniti Q45, Durango, C1500 truck, etc and haven't used/burned any oil in 7,000+ mile intervals. My Crossfire came from the factory recommending Mobil1 @ 7,500 miles changes, ha ha. Mobil1 ESP 0W-40 meets GM Service Fill Approval Dexos2.

That's all well and good when the engine is fresh and there's no leaks. But after years of use, poor maintenance, metal parts wear and tolerances open up. Valve stem seals shrink and internal leaks occur. Thin oil at cold start does lube the top end quicker, but until sufficient heat is built up, seals will still leak, and piston rings allow oil intrusion into the combustion chamber. Thicker oil will cling to bearing surfaces and will leak/intrude much less at startup than your 0 weight will.

And speaking specifically of bearing tolerances, please compare and contrast for me the specs between a 20+ year old, 200,000 mile Chevy 5.7 with a brand new German engine...

 

[Schurkey]

My objection to a big difference in the two numbers is that the difference is made up with viscosity improvers which will shear down in time, accelerated when there are gears. The actual oil viscosity can only be as thick as the W number permits - the rest is VIs.

Intuitively, it seems that actual oil between the moving parts is better than VIs.

I guess that's a valid concern. I remember when GM went on a rampage against 10W-40 oil--common as dirt at that time--because of VI concerns and "ring sticking".

At least, that's what they told us. Doesn't mean that's the real reason. This was when they were trying to launch "Goodwrench" motor oil; which of course didn't come in a 10W-40 version. Around 1983--'84.

I secretly thought it was a load of crap...but it's not like I had any research to support my position.

 

[Nad_Yvalhosert]

And I'd NEVER let the oil degrade 7000 miles in my truck. Talk about turning to sludge!

The use of a vehicle plays a key role in oil life. Tell me, how does your "Crossfire, Infiniti Q45, Durango, C1500 truck" do pulling an 18 ft landscaping trailer during the summer, and shoveling the snow outta the driveway with a 7.5" Western Unimount?

 

[Schurkey]

And I'd NEVER let the oil degrade 7000 miles in my truck. Talk about turning to sludge!

Define "degrade".

My Trailblazer goes about 13,000 miles (because that's when the Oil Life Monitor shows it needs to be changed), gets a fresh filter and oil topped-off. Then it goes another 13,000 miles before I dump the oil and change the filter again. Oil samples taken at 26,000 miles show oil is still fit for use. but I can't bring myself to go another 13,000 miles. I only have 250,000 miles on the vehicle, so I don't know how this is going to work out long-term, but "so far, so good" aside from the increase in oil consumption noted in my previous post.

Feedback fuel injection and overdrive transmissions have made major improvements in the service life of oil.

 

[PlayingWithTBI]

And speaking specifically of bearing tolerances, please compare and contrast for me the specs between a 20+ year old, 200,000 mile Chevy 5.7 with a brand new German engine...

And I'd NEVER let the oil degrade 7000 miles in my truck. Talk about turning to sludge!

Well, when I sold my Crossfire it had 186,000 miles on it and it didn't burn/lose 1/2 quart each interval plus NO SLUDGE!

Same with my 5.7L Chevy Mr Goodwrench engine. I have pics of it's lifter valley after over 200,000 miles and same thing, NO SLUDGE. Here's one, cheers!

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I remember when GM went on a rampage against 10W-40 oil

I personally think they needed the lighter weight oil to conform with CAFE MPG standards