automatic fuel management disaster in GM vehicles

[Alex_V]

Originally Posted By: TmanP
Oil consumption is a fact of life for some engine designs. Half a quart every 600 miles is a quart in 1200 miles. Toyota says in their owners manuals that "acceptable oil consumption" is a quart in 600 miles, or twice what you're experiencing. I believe that GM's threshold is a quart in 1200 miles. I wouldn't call that a disaster by any means.


Ehhhmm, I just made an overnight 750-mile run in my '85 GMC with 32 years and 126K on all the seals and gaskets, towing a CJ7 on a 7K car trailer at 60-70 MPH, getting avg. 8 MPG loaded (around 11 empty on the return trip - just as an example of how hard the engine was working) and it burned less than 1/2 quart of oil... with leaky oil cooler lines and valve covers, and valve seals that allow a puff of smoke on start-up.

IMHO the only decent excuse for a modern, conventional (non-race, etc.) engine to burn more than a quart every 2,000 mi. is if it was abused terribly its first 10,000 mi. or run with less than 25% of its intended oil capacity for any length of time, yet it's fairly common in several widely-used engine designs from different manufacturers.

While unrelated to Chevy's 5.3 conundrums it doesn't help that even if the new owner does care to crack open the owner's manual there's basically no special break-in procedure (maybe, don't tow for a few thousand miles or something) stated. In the face of the idea of "no need for break-in" with my '13 Cruze, I changed the oil at 2K, 6K, and 11K, gave it 30 seconds to a minute warm-up every day for the first 10K or so, and kept it away from redline for about the same amount of time, and at almost 94K the oil level doesn't change over the 5,000 mi. OCI's. Maybe a fluke, but maybe some kind of break-in does matter.

 

[SeaJay]

A quart every 1,200 or every 1,500 miles is a disaster in my book for a car on the road today, other than a 30 year old classic with a few hundred thousand miles on the clock.

 

[Arkandspark]

My wife's car is a 2013 Tahoe and it uses around the same amount of oil. About 3/4 of a quart for every 1000 miles or so. We purchased it with 15,000 miles on it. My wife drives like an old lady, I almost think the way she drives keeps it in 4 cylinder mode all the time causing it to burn oil. The dealer tells me its normal but I just cant wrap my head around it.

 

[jeepman3071]

There are a lot of newer vehicles that burn oil due to low tension piston rings, cylinder deactivation, etc. I wonder what all of this oil burning does to catalytic converters and O2 sensors.

My friend's dad has a 2007 Jeep Wrangler with the 3.8 V6. It burns about 1 quart every 1500 miles, which the dealer and manual say is normal. It only has ~60k miles on it, and the inside of the exhaust pipe is covered with thick black soot.

 

[demarpaint]

Originally Posted By: CKN
Originally Posted By: demarpaint
Originally Posted By: pacem
So I got a 2008 Tahoe with the AFM feature..

what an idiotic failure by GM. They had to take a good engine and screw it up big time without admitting it. They add features the public doesn't want or need, make things complicated and their QC is so poor that they fail.

My 5.3L sucks oil by the gallon. Half a quart of oil every two fill-ups. Or 600 miles. Ridiculous doesn't begin to describe it.

When I bought the car (used), it didn't register any oil at all on the dipstick. Had to add 2.5 quarts. Because you have to add oil on a weekly basis and evidently the PO wasn't checking it often enough.

I mean they are a multi-billion "dollar" corporation, they should act better than some garage start-up on a shoe-string budget and really test their stuff before releasing it to the public. They dropped the ball on it. There is a reason why used auto market heavily discounts GM versus say other brands. Because you may need to put several thousand into it when you get it. Case in point, engine mounts, another glorious design failure.

I am going to turn off the stupid 4-cyl mode and just hope it hasn't caused issues already. With lifters. 162K miles and 5000 hours on 5.3L.

I paid 6K for the vehicle, had to put another 2K in it to make it drivable. 8K is not bad but there is no way I would pay 50K for such an abysmal lack of QC/design stupidity. I doubt the new ones are any better.


I agree. The problem is the public always does the final testing for every new technology as they roll it out. CVT, DI, early EFI, you name it. The engineers don't always know best.

Sometimes they learn as they go, at the consumer's expense. Sometimes it takes years for them to learn. Then just when the get it right, the technology is obsolete and the cycle starts all over again with something else.

I stay clear of the first couple of years of any new technology. Even that is not always a guarantee there won't be problems.



Most on here would like to go back to the 1960's. So your not alone.


We don't have to go back that far. As long as I can continue to avoid CVT and DI until it is perfected I'm happy.

 

[pacem]

Originally Posted By: jeepman3071
There are a lot of newer vehicles that burn oil due to low tension piston rings, cylinder deactivation, etc. I wonder what all of this oil burning does to catalytic converters and O2 sensors.



I have a CEL for the O2 sensor. I pulled the codes. I wonder if that's related.

This is the last GM product I will buy, will likely get a Toyota next time. Or a Ford. GM vehicles seem to get incrementally worse. I had better luck with a 2006 Silverado, it was actually kind of reliable and did not burn oil with its 6.0L. I also had good luck with the B-bodies from the 1990's but these cars are 25 years old now and history for the most part.

The new, complicated, full of features and a corresponding high tag GM vehicles scary me.

 

[Brons2]

Back to the 60s and points ignition and carburetors? No way ever, if you gave me one of those cars the first thing I would do is put on solid state ignition and throttle body EFI. Probably a electronic transmission too.

 

[AZjeff]

Originally Posted By: pacem

This is the last GM product I will buy, will likely get a Toyota next time. Or a Ford. GM vehicles seem to get incrementally worse. I had better luck with a 2006 Silverado, it was actually kind of reliable and did not burn oil with its 6.0L. I also had good luck with the B-bodies from the 1990's but these cars are 25 years old now and history for the most part.

The new, complicated, full of features and a corresponding high tag GM vehicles scary me.


You bought a high mile truck at auction that showed signs of neglect and you say GM vehicles aren't reliable? Seems reasonable. Curious, were you aware of the potential problems with AFM in the Tahoe before you bought it?

 

[AZjeff]

I mean were you aware of AFM problems with these years of GM trucks before you bought this Tahoe, not if you suspected that problem with this particular one.