Oil Consumption

riddler · May 27

2024 HD LT8 6.6 gasser. Should I change to 5w-30 full synthetic to reduce oil consumption?

jake111 · May 27

1) The 6.6L L8T gasser already calls for synthetic 5w-30. That's what should already be in it.

2) The L8T does not have DFM. If one cylinder is guzzling, they're all guzzling.

Your article is probably talking about the L87 in the 1500 trucks and other models, and yes, 0s-20 was too thing and caused big problems.

jake111 · May 27

(posted twice for some reason. please delete)

Edited May 27 by jake111
duplicate post

newdude · May 27

9 hours ago, riddler said:

2024 HD LT8 6.6 gasser. Should I change to 5w-30 full synthetic to reduce oil consumption?

Your truck already uses 5w-30 full synthetic.

If you aren't burning oil, don't change a thing.

If you are, use something like Valvoline Restore and Protect or that new Mobil 1 Advance Clean in the same 5w-30 weight.

Edited May 27 by newdude

MORSNO · May 27

HD truck engines and transmissions, although similar, are quite different so make sure you're looking at the correct information. The internet doesn't always provide the most accurate information as much is AI created and full of mistakes currently.

riddler · May 27

IM looking for anyone who has specific knowledge of my question. Not a lecture on internet etiquette.

riddler · May 27

Thanks @newdude I am burning oil. I will try a brand as you suggested.

riddler · May 27

Thanks @jake111 just trying to fix the oil consumption

newdude · May 27

7 minutes ago, riddler said:

Thanks @newdude I am burning oil. I will try a brand as you suggested.

I have experience only with the Valvoline but it does work. Got a 2009 Vibe 2.4 with 245,500mi on it (bought it with 234,000) that I took from a quart in 400mi down to a quart in 2500mi using Valvoline Restore and Protect.

Assuming you have ZERO leaks (oil cooler lines are common on these trucks), the consumption is likely from the oil control rings being carbon'd up.

How much oil is it using? HD trucks, GM measures in quart/100gal of fuel. NOT by quart/x amount of miles. Anything in excess of that is excessive. Some consumption is normal to a degree, especially if it is worked hard all the time.

Edited May 27 by newdude

KARNUT · May 27

Has it used oil from new? How much is it using? I’ve had two vehicles use oil from new. Both a qt every 2500 miles. Never got worse. If you’re under warranty still. Bring it to their attention.

riddler · May 27

4 hours ago, newdude said:

I have experience only with the Valvoline but it does work. Got a 2009 Vibe 2.4 with 245,500mi on it (bought it with 234,000) that I took from a quart in 400mi down to a quart in 2500mi using Valvoline Restore and Protect.

Assuming you have ZERO leaks (oil cooler lines are common on these trucks), the consumption is likely from the oil control rings being carbon'd up.

How much oil is it using? HD trucks, GM measures in quart/100gal of fuel. NOT by quart/x amount of miles. Anything in excess of that is excessive. Some consumption is normal to a degree, especially if it is worked hard all the time.

Thanks for the info. No leaks using about a qt every 3k. I have 31k on it been burning oil since 20k. I will put Valvoline in it my next oil change.

riddler · May 27

4 hours ago, KARNUT said:

Has it used oil from new? How much is it using? I’ve had two vehicles use oil from new. Both a qt every 2500 miles. Never got worse. If you’re under warranty still. Bring it to their attention.

since 20k I have 31k now. thanks

newdude · May 27

54 minutes ago, riddler said:

Thanks for the info. No leaks using about a qt every 3k. I have 31k on it been burning oil since 20k. I will put Valvoline in it my next oil change.

A quart in 3000mi is nothing, but again, GM measures HD consumption on quart/100 gallons of fuel. But you'd have to be getting 30mpg during that 100 gallons of fuel use to equal a quart in 3000mi.

You are nowhere near that amount it sounds like, but wouldn't hurt to switch oil now to keep it from getting worse.

riddler · May 27

46 minutes ago, newdude said:

A quart in 3000mi is nothing, but again, GM measures HD consumption on quart/100 gallons of fuel. But you'd have to be getting 30mpg during that 100 gallons of fuel use to equal a quart in 3000mi.

You are nowhere near that amount it sounds like, but wouldn't hurt to switch oil now to keep it from getting worse.

I wouldnt say its nothing. Ive never owned a vehicle that burned 1 drop in 3k miles. I guess we have to accept what GM says...

Chuck FB · May 27

1 hour ago, riddler said:

I wouldnt say its nothing. Ive never owned a vehicle that burned 1 drop in 3k miles. I guess we have to accept what GM says...

What has your oil change interval typically been in miles. Also are you hauling/towing heavy or lightly loaded, and speed would be a factor as well as high speeds mean more hp being used to force the brick through the air.

I can't claim this as its not as if I have seen an L8T piston beside an older series of GM engine but the theme these days is thin rings and in some cases smaller holes through the piston within the oil control ring groove and due to that it seems more prone to those small passages plugging. And I think GDI has something to do with that as well with increased carbon being created. Put that together with perhaps not a short enough oil change interval and it catches up to the engine.