Burning Oil

[kevymetal]

I scrolled through a few pages looking for another post on the issue with no luck, so I apologize if this has come up before.

 

I have a 2021 Silverado 1500 Custom, 5.3L 6 speed. About 80k km on it. A couple months ago I had it parked on a bit of a hill outside my office, facing uphill. Probably had been sitting for a couple hours since I last drove it. I started it up and a big cloud of blue/black smoke came out of the tail pipes and smelled like burnt oil. Smoke cleared pretty quick and that was it. I didn't see this happen again for another few weeks, but once again, parked the exact same way as before, I started it up and a huge cloud of smoke and burnt oil smell. I had parked the same way lots of times in between both smoke shows. I haven't seen it do this since. 

 

I had it in at Chev today for an oil change and the tailgate recall and I told them about this. They had a red seal tech check it out. No signs of leaking valves, no codes thrown and he couldn't recreate it. They charged me $170 to tell me they couldn't find anything wrong except the oil level was low (but they didn't say by how much) but that it's normal for these trucks to burn 3L or so of oil every 10k km. They even had documentation from GM Canada backing that up. But just to be safe, they want to track the oil consumption and every 1000km, I have to go back to the dealership, let the truck sit for 15 min and then they check the oil level and log it. I'm in the last 20k km of my powertrain warranty so if something is going on, I want to get it dealt with before it costs me. Anyone experience something similar? My buddy suggested adding a catch can, but to also have the valves and rocker taken apart and cleaned out. This is way above my skill set and sounds expensive. 

 

I don't buy the "this is normal operation" argument because if it was, I would have seen it happening sooner. My driveway is level and I've never seen it happen when I start it at home, so I definitely think hill parking it is a piece of the puzzle. 

[newdude]

Just now, kevymetal said:

I scrolled through a few pages looking for another post on the issue with no luck, so I apologize if this has come up before.

 

I have a 2021 Silverado 1500 Custom, 5.3L 6 speed. About 80k km on it. A couple months ago I had it parked on a bit of a hill outside my office, facing uphill. Probably had been sitting for a couple hours since I last drove it. I started it up and a big cloud of blue/black smoke came out of the tail pipes and smelled like burnt oil. Smoke cleared pretty quick and that was it. I didn't see this happen again for another few weeks, but once again, parked the exact same way as before, I started it up and a huge cloud of smoke and burnt oil smell. I had parked the same way lots of times in between both smoke shows. I haven't seen it do this since. 

 

I had it in at Chev today for an oil change and the tailgate recall and I told them about this. They had a red seal tech check it out. No signs of leaking valves, no codes thrown and he couldn't recreate it. They charged me $170 to tell me they couldn't find anything wrong except the oil level was low (but they didn't say by how much) but that it's normal for these trucks to burn 3L or so of oil every 10k km. They even had documentation from GM Canada backing that up. But just to be safe, they want to track the oil consumption and every 1000km, I have to go back to the dealership, let the truck sit for 15 min and then they check the oil level and log it. I'm in the last 20k km of my powertrain warranty so if something is going on, I want to get it dealt with before it costs me. Anyone experience something similar? My buddy suggested adding a catch can, but to also have the valves and rocker taken apart and cleaned out. This is way above my skill set and sounds expensive. 

 

I don't buy the "this is normal operation" argument because if it was, I would have seen it happening sooner. My driveway is level and I've never seen it happen when I start it at home, so I definitely think hill parking it is a piece of the puzzle. 

 

 

GM oil consumption limits is 1 quart in 2,000mi/3,200km, not in 1,000km.  

 

Catch can won't stop a full on consumption issue.

 

First step is check for leaks.  Oil cooler lines are very common on this generation truck. 

 

Smoke on cold starts on these engines is most commonly caused from the direct injection fuel injectors which pulse extra fuel on a cold start.  It is mostly black, possibly a blue tint.  If your smoke was mostly all blueish smoke, then oil is a possibility.

 

If it is burning it, its getting past the piston rings, and if that's the case, they are probably carboned up and is what is causing that.  Its possible to try and chemically free the rings with something like BG EPR treatment, but if that doesn't touch it, it would require new rings and likely pistons.  

 

Oil consumption to a degree is normal though.  High RPMs, high loads like lots of WOT or towing can all increase consumption.  

[kevymetal]

The dealership is saying 3L/ 10,000km is normal, so that's why they are checking every 1000km to see if there is a consumption issue. 

 

I'll have a look for leaks. You would think their mechanic already did that, but who knows?

 

I've heard about the direct injection fuel injectors the pulsing extra fuel in a cold start, but I don't think that's what I'm seeing, because I feel like I would see smoke more frequently and not just those 2 times parked on a hill. 

 

I really hope it's not a piston/ring issue, but if it was, I'm guessing that would be covered under the powertrain warranty? How would I prove that's the problem though?

 

I understand oil consumption is normal. I'm just a bit shocked they didn't see how much oil was gone when they did the oil change, especially since I brought up the concern of it possibly burning excessive oil.

[SteveP45]

I had a similar issue on an older Silverado and it was the tiny o ring on the valves if a few cylinders, but it was a older 2004 with 6 digit miles on it.

 

No problems yet on my 2019 which I purchased new and has 70k+ miles on it.
 

How long of an interval do you go between oil and filter changes?   I have a 2019, but I change it at 6k miles (9.6k km) or less.   I do not let the oil life left indicator dictate when to change.   
 

In my humble opinion 10k miles  (16k km) is way too long.

 

I know you did not mentioned any oil drippings, but if you have a dealer or quick lube do your oil change, make sure they are using correct filter and that it is tightened… also make sure they are putting in 8 quarts.   Most businesses do not employ a certified mechanic for oil change or tire rotation.    Never seen any check the oil level before they take out the crankcase drain bolt.  
 

I would never take my vehicle to a quick lube.   If I can’t change it myself, I take it to the dealer.
 

If you do not do your own changes, check the oil level afterwards.

[kevymetal]

3 minutes ago, SteveP45 said:

I had a similar issue on an older Silverado and it was the tiny o ring on the valves if a few cylinders, but it was a older 2004 with 6 digit miles on it.

 

No problems yet on my 2019 which I purchased new and has 70k+ miles on it.
 

How long of an interval do you go between oil and filter changes?   I have a 2019, but I change it at 6k miles (9.6k km) or less.   I do not let the oil life left indicator dictate when to change.   
 

In my humble opinion 10k miles  (16k km) is way too long.

 

I know you did not mentioned any oil drippings, but if you have a dealer or quick lube do your oil change, make sure they are using correct filter and that it is tightened… also make sure they are putting in 8 quarts.   Most businesses do not employ a certified mechanic for oil change or tire rotation.    Never seen any check the oil level before they take out the crankcase drain bolt.  
 

I would never take my vehicle to a quick lube.   If I can’t change it myself, I take it to the dealer.
 

If you do not do your own changes, check the oil level afterwards.

When I bought the truck I got talked into the maintenance package so all of my oil changes are essentially pre paid at the dealership until 2026. I would assume the dealership lube techs are doing the changes to GM spec. I do go by the oil interval indicator in the truck though. My truck works pretty hard, I'm a construction manager so I tow and haul with it a fair bit, and I spend a bit of time with it off road on weekends so it never makes it to 16k km. I usually get about 10k km for an interval.

 

The only reason they would have checked the oil level before draining this time was because I brought up the burning oil issue. They had one of their red seal techs looking at things before they did the oil change and he found the level to be low. Why he didn't see how low I don't know.

[Grumpy Bear]

12 hours ago, newdude said:

If it is burning it, its getting past the piston rings, and if that's the case, they are probably carboned up and is what is causing that.  Its possible to try and chemically free the rings with something like BG EPR treatment, but if that doesn't touch it, it would require new rings and likely pistons. 

 

^^^^^^^^^^^^^

This

 

OCI is way to long for a GM provided Dexos licensed oil. 4K to 5K kilometers. I doubt BG ERP would free those rings. (Been there, did that). Possible, yea, likely, not. Even if it did, continuing with this oil regiment will lead you right back to the same issue shortly. 

Edited June 6 by Grumpy Bear

[kevymetal]

6 minutes ago, Grumpy Bear said:

 

^^^^^^^^^^^^^

This

 

OCI is way to long for a GM provided Dexos licensed oil. 4 to 5 kilometers. I doubt BG ERP would free those rings. (Been there, did that). Possible, yea, likely, not. Even if it did, continuing with this oil regiment will lead you right back to the same issue shortly. 

So should I be going back to Chev and telling them to check the pistons and rings for build up?

[diyer2]

My thoughts also. 

[diyer2]

Do you know the procedure to check the rings and pistons for carbon build up?

[kevymetal]

1 hour ago, diyer2 said:

Do you know the procedure to check the rings and pistons for carbon build up?

Aside from the crank case pressure oil cap test?

[Grumpy Bear]

2 hours ago, kevymetal said:

So should I be going back to Chev and telling them to check the pistons and rings for build up?

 

You are under warranty. Let them play this out. They are doing the oil consumption test, correct? 

[kevymetal]

2 minutes ago, Grumpy Bear said:

 

You are under warranty. Let them play this out. They are doing the oil consumption test, correct? 

Yes, I am under warranty still and yes, we have started the oil consumption test. I'm just trying to educate myself. They charged me $170 for diagnostics yesterday because "they didn't find anything wrong". Basically, they will keep charging me their hourly shop rate to try and diagnose the issue, until they find it and determine it's covered under warranty. Even though the advisor agreed with me something seems suspicious. 

[newdude]

18 minutes ago, kevymetal said:

Yes, I am under warranty still and yes, we have started the oil consumption test. I'm just trying to educate myself. They charged me $170 for diagnostics yesterday because "they didn't find anything wrong". Basically, they will keep charging me their hourly shop rate to try and diagnose the issue, until they find it and determine it's covered under warranty. Even though the advisor agreed with me something seems suspicious. 

 

 

What you need to do is have them start an oil consumption test to verify how much is being consumed.  

[newdude]

2 hours ago, kevymetal said:

So should I be going back to Chev and telling them to check the pistons and rings for build up?

 

 

They aren't going to open up your engine, not without a verified oil consumption test.  

[kevymetal]

3 minutes ago, newdude said:

 

 

What you need to do is have them start an oil consumption test to verify how much is being consumed.  

I've said 3 times in this thread that we've started an oil consumption test....