08 5.3 Sierra Oil Recommendations

Joined
Jun 6, 2017
Messages
190
Location
FL, USA
Need oil recommendations for the 5.3L. Manual calls for 5w30 but going through the last owner's maintenance records shows the shop he was using was filling it with 5w20(???). I recently stepped up to 5w30 like the manual says. I have heard others with this engine like 5w40.

Some background on the truck:

Low mileage. AFM is disabled with a Range device. Still have the HW :-( I am the 3rd owner. Truck runs strong and sounds great. I don't tow anything right now and from what I understand the previous owner did pretty light towing (motorcycles). Just did a recent tune up (plugs/wires/airfilter) and flushed the brakes and PS (dark brown). Need to flush the coolant next (probably original but still orange). Tranny was flushed at 50k and a new control module added (to fix a shifting issue). I changed the oil to some 5w30 syn from costco w/ a microgard filter that I had in the garage - seemed better than whatever was in there before (dark). Doesn't seem to consume any oil but time will tell.
 
Caveat: This may sound like a lot but it's really not.

You mentioned Low Mileage. How low is low? :) Those SMC's are good engines.
How will you be using your truck?
Does your owner's manual even list a 5W20 for any outside temp?
Will you be changing your own oil & filter?

I've gone to full synthetic oils mainly due to the price being so close to conventional oils now

Use the correct oil recommended in your owner's manual, according to how the truck will be used and what the outside temperature will be for that particular oil change interval(OCI). And don't worry about those one or two days(or even a week) where the outside temp is different during that OCI.

To me, a 5W30 all day long in FL if this is just your transportation vehicle.
If you're really towing a heavy load just once or twice during that particular oil change interval(OCI), there is no need to change the oil to a heavier grade just for that.

However, if you'll be towing/hauling a lot during that particular OCI, you may want to consider a heavier grade oil that is recommended in the owner's manual.
 
Have an 08 Silverado with a 4.8–same engine family minus the troublesome AFM. I run 5W30 full syn, whatever major brand with an extended performance oil is cheapest at Walmart, with either an acdelco filter or a fram tough guard filter.

I change the oil when the vehicle tells me to and last oil change that was after 9500 miles. Engine has 206xxx miles. My Grandfather owned it before me; it was dealer maintained and he too would change it according to the OLM.

With AFM on your truck, I’d be inclined to shorten the OCI In hopes of keeping those lifters happy for a longer period of time. What that shortened OCI might be is really up to you. Perhaps others with more knowledge of preventing AFM issues can chime in on shortened OCIs!
 
With AFM on your truck, I’d be inclined to shorten the OCI In hopes of keeping those lifters happy for a longer period of time. What that shortened OCI might be is really up to you. Perhaps others with more knowledge of preventing AFM issues can chime in on shortened OCIs!
This is my main concern. I will be using the truck for light duty. But I want it to stay reliable. Going synthetic was a no brainer with AFM. I have heard on the GM forums not to follow the maintenance recommendation. Change the oil when it gets to 50% because the AFM is more sensitive to oil and use synthetic only.

Caveat: This may sound like a lot but it's really not.

You mentioned Low Mileage. How low is low? Those SMC's are good engines.
How will you be using your truck?
Does your owner's manual even list a 5W20 for any outside temp?
Will you be changing your own oil & filter?

I've gone to full synthetic oils mainly due to the price being so close to conventional oils now

Use the correct oil recommended in your owner's manual, according to how the truck will be used and what the outside temperature will be for that particular oil change interval(OCI). And don't worry about those one or two days(or even a week) where the outside temp is different during that OCI.

To me, a 5W30 all day long in FL if this is just your transportation vehicle.
If you're really towing a heavy load just once or twice during that particular oil change interval(OCI), there is no need to change the oil to a heavier grade just for that.

However, if you'll be towing/hauling a lot during that particular OCI, you may want to consider a heavier grade oil that is recommended in the owner's manual.

You mentioned Low Mileage. How low is low? 54k Those SMC's are good engines. They are but AFM is a problem.
How will you be using your truck? Light Duty
Does your owner's manual even list a 5W20 for any outside temp? No
Will you be changing your own oil & filter? Yes
 
This is my main concern. I will be using the truck for light duty. But I want it to stay reliable. Going synthetic was a no brainer with AFM. I have heard on the GM forums not to follow the maintenance recommendation. Change the oil when it gets to 50% because the AFM is more sensitive to oil and use synthetic only.
50% would probably correspond to about 5000 mile OCIs. I’m really not certain what’s best practice for those engines, but that doesn’t sound like a bad idea. Perhaps just use whatever flavor of basic full sun 5W30 you like with the latest specs. With an OCI like that, don’t see much benefit of running an extended performance oil, but the price difference is still under $10 for a 5 quart jug (think regular M1 vs M1 Extended) so really whatever floats your boat lol!
 
50% would probably correspond to about 5000 mile OCIs.
I think the OCI is 7500 on the MM. There are a number of factors that goes into how the computer calculates it but I have heard others state once you hit 7500 it automatically goes to 0%.

Other posts on this forum regarding this engine state all normal BITOG thought - "I'm running a 10k, 15k, 20k OCI!!" gets thrown out the window with this engine because of the AFM system. These engines need shorter OCI to preserve the AFM lifters which are prone to failure.
 
Costco syn is good oil. 5w-30 in FL is good although you probably won't have any trouble with 5w-20. If it were my wifes vehicle I'd change it every 5k miles because of the AFM hardware.
 
AFM isn’t the only thing to keep working. The oil screen can get dirty and clogged as well.
I don't want the AFM working, that is why I deactivated it. I want the lifters to keep working lol. Are you talking about the screen behind the oil pressure sensor (on the manifold)? Does that get used if AFM is not engaged?
 
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I don't want the AFM working, that is why I deactivated it. I want the lifters to keep working lol. Are you talking about the screen behind thr oil pressure sensor (on the manifold)? Does that get used if AFM is not engaged?
Yes and as far as I know, it is still in operation even with AFM disabled.

I meant working as in keeping clean oil going if using it. Obviously you said you used the Range AFM disabler to disable it. ;)
 
I think the OCI is 7500 on the MM. There are a number of factors that goes into how the computer calculates it but I have heard others state once you hit 7500 it automatically goes to 0%.

Other posts on this forum regarding this engine state all normal BITOG thought - "I'm running a 10k, 15k, 20k OCI!!" gets thrown out the window with this engine because of the AFM system. These engines need shorter OCI to preserve the AFM lifters which are prone to failure.
Perhaps my non-AFM equipped 4.8 has a different calculus to the percentage countdown because the last oil change went 9500 miles and I was around 2% if I remember correctly. Certainly didn’t run it 2000 miles past while at 0% lol! I think you have a good game plan though!
 
Why not a quality 0W-30, 5W-30, 0W-40, 5W-40?
My son's 2013 5.3L 1500 has over 200K miles of mostly off road and/or towing, all on XW40 something.
(even 0W40 M1 Euro a few times Buster 'n Overkill)
Usually he goes way over the olm.
The truck is on its 3rd set of front hubs.
 
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Perhaps my non-AFM equipped 4.8 has a different calculus to the percentage countdown because the last oil change went 9500 miles and I was around 2% if I remember correctly. Certainly didn’t run it 2000 miles past while at 0% lol! I think you have a good game plan though!
My 05 4.8 goes about 4k miles on the olm. I think the number of starts and temperature fluctuations is what sucks mine down faster. Maybe that and full throttle merging onto the highway.
 
My 05 4.8 goes about 4k miles on the olm. I think the number of starts and temperature fluctuations is what sucks mine down faster. Maybe that and full throttle merging onto the highway.
That’s a possibility. The truck serves as an extra vehicle in the family and when it’s used, it generally has a drive cycle long enough to get the oil up to full temp.
 
My son's 2013 5.3L 1500 has over 200K miles of mostly off road and/or towing, all on XW40 something.
(even 0W40 M1 Euro a few times Buster 'n Overkill)
Usually he goes way over the olm.
The truck is on its 3rd set of front hubs.
It was more rhetorical than anything.
 
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