Oil consumption, no smoke, no leaks

White smoke is usually coolant burning, but you say no loss of coolant, so must be oil burning. PCV is possible fault, especially since you say smoke is intermittent. Part itself should be cheap, less than $20. One your car I believe it is located in a pipe running from intake to valve cover.

just about everyone does with either an old car or a new car with high mileage.how excessive? is oil consumption.well first thing is to check for oil leaks either underneath the motor or any oil lines feed into the motor .any major leaks would be pretty noticeable.if none are present then one would assume that your motor is burning the oil through the exhaust system .check to see what color smoke is coming threw the tail pipe.blue or black smoke indicates oil burning white will indicate engine coolant burning.in any case some color smoke is normal just depends on how much.so lets say your exhaust smoke is normal still could be burning oil just not a noticeable amount.on average you shouldnt have to add anymore than 2 quarts a month or every 1000 miles .depending on your driving conditions if you are having to add more than this there would be a leak some where or heavy color smoke.keep up on oil changes and always add lucas oil usually 1 quart its alot thicker than conventional oil so it reduces engine wear and will handle any small leaks in the engine components like the pistons and rings.if problem still present get to a dealer or certified mechanic as soon as possible good luck.

Google search GM 5.3 oil consumption. This is a known and common issue.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

It can easily burn that much in a 100 miles without seeing any smoke.
If you check the spark plugs you may find evidence.
It can also leak while the engine is running and not when it is off. Most Northstar engines leak to some degree.

WHITE smoke? Or BLUE smoke? White smoke is usually caused by burning antifreeze (possible blown head gasket). Engine oil burning causes a bluish colored smoke.

Changing the oil two months ago means absolutely nothing to me. I have customers that travel 6000 miles or more in a month. Oil consumption is measured in volume over miles, not volume over months. It is normal for most 4 cylinder engines to use a little less than 1/2 quart in 1000 miles (even more than that for 6 cylinder and 8 cylinder engines).

For that type of oil consumption there must be traces of smoke at some time. If there is smoke at start-up and when you lift your foot off the pedal to slow down, the valve stem seals are leaking. If the smoke is predominantly seem under acceleration and normal driving, the oil seal rings are allowing oil into the cylinder/s. At present the oil consumption and cost (if there is no excessive smoke) will be a lit less than the repair of either of the factors I have mentioned above. Try changing to another brand of oil (synthetic oil seem to contribute to high oil consumption). Try a heavier brand of mineral oil, at least a 20W-50 or even a 60 for older engines. Go for an oil that is marketed and backed by a reputable company with a petroleum back round.

I just bought a 2005 envoy too. I read in the manual that the 4.6 6 cyl engine needs 7 qts total. 2 Over the normal oil change. Is it possible it wasn't low to start? I noticed when Walmart changed the oil they charged extra for the change because it needed the two extra qts. However my dip stick has oil over the full mark. Seemed strange but I haven't had any leaks and after 3k mile no change in level. Make sure you had the correct about the first time.

At 40K miles it shouldn't burn that much oil, unless the motor has been abused or overheated. With no signs of oil leaks, the engine must be burning it via the exhaust,

Change the oil (use a good quality oil) and then observe oil consumption.

If it still uses excessive oil check further as below:-
1) if it blows blue smoke on steady accelleration (pistons or ring wear),
or
2) only blows blue smoke on initial accelleration after a period of steady coasting or de-celleration (faulty valve stem oil seals).

Yes a crappy PVC valve can cause some of your problems but not necessarily all of them, they are cheap, I always replace it to start. The air cleaner housing being full of oil is like how the oil is being consumed. In addition to a PVC valve, there may also be a blow-by hose running into the housing. check to see what other hoses go into the housing & which ones have oil coming from them. I'm not familiar with the "Motor Honey" you mentioned but I rarely add additives to my Engine oil, especially if they are thickeners. The only stuff I recommend is a Quaker state or similar "High Mileage Oil". These semi-synthetic oils have additives to swell old rubber & cork seals in older engines and can help reduce oil consumption & leakage. Again, it may not be a total solution, but it couldn't hurt to drain out all of the existing oil & replace with a high mileage type & also change the filter at the same time. Never mix it with other oils, despite the manufacturer telling you it may be safe to do so.

No, it's not unusual to have to put a quart in within those miles'