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Oil Consumption

DropTop5.0

DropTop5.0

Well-known member
Back again with more stupid questions. I bought my truck with an understanding that the 8.1L eats oil. I checked the oil religiously for the first 8,000 miles or so but I've been a little lazy in the last couple months as its been a colder. I checked it last night and I was about 1.5 quarts down. :brickwall:

I use OEM suggested 5W30 weight oil (Sorry Ron). Do vehicles tend to burn more oil in colder temperatures than in warmer temperatures? Is it the 5W that may lend to the oil consumption? Its my understanding that 5W30 oil acts like 5 weight oil when cold and 30 weight when warmed up.

I've been thinking of switching over to synthetic but I haven't done it yet. Seems like that might give me a touch of extra protection just in case it runs low again.
 
Full synthetic of the weight you use will be thinner and make it worse. Yea, I run Mobil One 15-50w in mine along with a quart of Lucas Syn Oil Stabilizer and I use hardly any between oil changes anymore with beautiful oil pressures even when cold with the syn. When i switched from 10-30 dino to 10-30 syn, I would lose oil pressure drastically above 4000 rpm so I went to the heavier weight syn. No more issues. 5-30 IMO is just too thin for a loose factory BBC with low tension oil rings (that is where your oil goes just like marine bbc's).

Other thing to check and replace are the engine oil cooler lines. The quick connect fittings on the block are notorious for leaking and I know mine need to be replaced. Its an 8.1 thing.
 
That's some good info. I've got the 2012 5.3 liter with the stupid AFM (automatic fuel management)system, which is known to burn a quart of oil. I also run 5w 30 full synthetic mobil one. I'm gonna order the range delete to turn off the AFM, plus it burns gas with it activated. Hopefully that will take of the oil and gas problem. I'm wondering if I could go to a thicker oil as well?
 
A thicker oil would help there as well. With the AFM, the deactivated cylinders have little to no cylinder pressure to spread and seal the rings when in 4 cylinder mode so some oil gets by the rings. The 0 and 5 weight oils are mostly used to help with emissions and fuel economy of the motors. I imagine going to a nice 10-40w in the small blocks would help out a lot. I do like the AFM and have changed tje programming on a friends truck to be really agressive and be in the 4 cyl mode more. Made change between 4 and 8 cyls very noticable, but would not constantly waffle between the two and got some seriously good mileage in a lifted truck.

As far as Im concerned, Rotella T is one of the best universal engine oils for diesel or gas. Most of the endurance fleet oils are truly amazing products compared to the over marketed consumer auto oils.
 
Gimme Fuel said:
A thicker oil would help there as well. With the AFM, the deactivated cylinders have little to no cylinder pressure to spread and seal the rings when in 4 cylinder mode so some oil gets by the rings. The 0 and 5 weight oils are mostly used to help with emissions and fuel economy of the motors. I imagine going to a nice 10-40w in the small blocks would help out a lot. I do like the AFM and have changed tje programming on a friends truck to be really agressive and be in the 4 cyl mode more. Made change between 4 and 8 cyls very noticable, but would not constantly waffle between the two and got some seriously good mileage in a lifted truck.

As far as Im concerned, Rotella T is one of the best universal engine oils for diesel or gas. Most of the endurance fleet oils are truly amazing products compared to the over marketed consumer auto oils.
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That's the part I don't like about the AFM, it waffles in between 4 and 8 cyls mode. So I need to get the AFM programmed to shift better between the two? Supposedly the DiabloSport inTune is one of the best on the market according to the guys over on the http://www.silveradosierra.com/ site? Your thoughts on this?
 
Chris I can't remember if your truck in equipped with a PCV valve but if so replace it. PCV valves can cause oil burn and a new one cost less than $10.00. Make sure to use only GM or ACDelco as the aftermarket valves cause issues.
 
Great, thanks guys. I'm not leaking anywhere so it has to be burning it. Replacing a $10 part is good insurance. From what I read the 8.1 can easily burn a quart very couple thousand miles which is what I just did, but it's the first time. Makes me wonder what changed to make it happen.
 
DropTop5.0 said:
Great, thanks guys. I'm not leaking anywhere so it has to be burning it. Replacing a $10 part is good insurance. From what I read the 8.1 can easily burn a quart very couple thousand miles which is what I just did, but it's the first time. Makes me wonder what changed to make it happen.
Click to expand...

Extreme cold weather can make engines do weird things sometimes. Give a few minutes to warm up and let the rings seal.

BTW how long are you going between oil changes on that dino oil?
 
DropTop5.0 said:
Great, thanks guys. I'm not leaking anywhere so it has to be burning it. Replacing a $10 part is good insurance. From what I read the 8.1 can easily burn a quart very couple thousand miles which is what I just did, but it's the first time. Makes me wonder what changed to make it happen.
Click to expand...
The factory tune on the 8.1 is also extremely lean at WOT. When I dynoed mine, I had a 15.7-1 AFR at WOT! No wonder why they are hard on rings and consume oil. That is part of the culprit, especially if they were ever worked hard.
 
Rob B said:
That's the part I don't like about the AFM, it waffles in between 4 and 8 cyls mode. So I need to get the AFM programmed to shift better between the two? Supposedly the DiabloSport inTune is one of the best on the market according to the guys over on the http://www.silveradosierra.com/ site? Your thoughts on this?
Click to expand...
I did a custom tune on the one I messed with using HPTuners software. It lets you use your laptop to modify absolutely any part of the program including removal of funky torque management/traction control.

On my 8.1 I did have a Quadzilla Gas tuner on mine but with my 4.10 gearing, the shift points were too close to the rev limiter so with the quickly climbing rpm of the lower gearing, it would bounce on the rev limiter and not shift at WOT. Plus the tuner had full fuel enrichment engaged at lower rpm so fuel economy did not improve. With the Custom Tune, I netted about the same increase in HP with HP Tuners but drastically improved the economy by setting the shift points very low below 50% TPS input. She has almost the torque of a diesel, so why not shift her like one. Saves fuel. I also moved my trans line pressures to the max, and cut shift times in half. Gives nice firm shifts yet not harsh. I also force converter lock up above 30 mph except when in tow haul mode, I left that alone for most parts except for line pressures and shift times. That button toggles between two entirely different trans programs. Kinda nifty. Like having a "race" mode haha.

I also disabled EGR so it is a clean air intake only engine!
 
Gimme Fuel said:
I did a custom tune on the one I messed with using HPTuners software. It lets you use your laptop to modify absolutely any part of the program including removal of funky torque management/traction control.

On my 8.1 I did have a Quadzilla Gas tuner on mine but with my 4.10 gearing, the shift points were too close to the rev limiter so with the quickly climbing rpm of the lower gearing, it would bounce on the rev limiter and not shift at WOT. Plus the tuner had full fuel enrichment engaged at lower rpm so fuel economy did not improve. With the Custom Tune, I netted about the same increase in HP with HP Tuners but drastically improved the economy by setting the shift points very low below 50% TPS input. She has almost the torque of a diesel, so why not shift her like one. Saves fuel. I also moved my trans line pressures to the max, and cut shift times in half. Gives nice firm shifts yet not harsh. I also force converter lock up above 30 mph except when in tow haul mode, I left that alone for most parts except for line pressures and shift times. That button toggles between two entirely different trans programs. Kinda nifty. Like having a "race" mode haha.

I also disabled EGR so it is a clean air intake only engine!
Click to expand...

Damn!! That's way over my head :o. I'll probably get someone knowledgeable to program mine. I assumed the tune was a plug and play.
 
Chris I didn't mean to highjack your thread, sorry! There's good info on this topic. Glad we have guys on forum that know truck mota's or mota's in general!:thumb:
 
If you just get a simple programmer, a caveman could do it. If you want to custom tune everything with a laptop, a Chewbacca can do that.
 
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