Missing Oil Mystery

I have an '08 Dodge Avenger with less than 100K miles on it. Oil is changed every 4000 to 6000 miles, and a new filter installed. Before I get 3000 miles on the oil change I have to add nearly a quart of oil. There is no evidence of oil leaking; there is no evidence of oil burning sediment on the tailpipes. Yes, after changing the oil I do run the engine to make sure the filter is full & then check the oil level to make sure it’s still full. Can anyone give me a hint on where the oil goes? What should I do about this?

Check the condition of your coolant to be sure you don’t have oil getting into the cooling system via a bad head gasket. Otherwise, the oil is just burning off and 1 qt every 3K miles isn’t really a problem.

Did you buy this car new? How much care in breaking in the engine the first 500 miles?

If it’s not leaking as determined by physically checking the undercarrriage and verifying it is bone dry then it’s burning it.

The converters are probably catching most of it and odds are if the converters were torn open one would find coked oil on the honeycomb. What eventually breaks free and passes through the converter will eventually get blown out the tailpipe.

Check the PCV system and follow that up with a compression test.

You are doing the right thing by checking your oil. As suggested, checking the PCV system may be in order. However, one quart per 3000 miles is not out of line. The owners manual on my 2011 Toyota Sienna says that 1 quart in 750 miles is acceptable. I have never had to add oil, but apparently this rate of consumption is not considered out of line by Toyota.
If the PCV system checks out and there are no oil leaks, I wouldn’t worry about adding a quart in 3000 miles. Sometimes changing brands of oil (but not viscosity) may help. I had a Ford Maverick and added a quart every 1000 miles when I used Sunoco 10W-40. My oil rate improved to 1 quart every 1250 miles when I used Valvoline 10W-40.

No evidence of oil in coolant. I bought the car new, and broke it in as prescribed. Have physically crawled under car and verified all is bone dry. PCV system is next on the list to checkout. I appreciate all the comments.
Have driven various Chrysler products for 30+ years and never had a vehicle that used oil in this quantity. Have always used Castrol GTX 10W-30 and never (until now) had a problem.

“Have driven various Chrysler products for 30+ years and never had a vehicle that used oil in this quantity”.
Obviously you never owned a 1947 or 1949 Dodge. My dad owned these cars and oil consumption was a real problem. These cars got to the point where they consumed a quart of oil every 300 miles. A quart of oil every 3000 miles is not a problem in my book. My brother bought a used 1977 Cadillac back in 1983. It used a quart every 900 miles. He put 150,000 miles on the car in addition to what it already had. The oil consumption remained at a quart every 900 miles.
You are doing one thing right and one thing wrong. You are doing the right thing by checking your oil frequently and adding a quart when needed. You are doing the wrong thing by worrying about adding the quart at 3000 miles. Some cars are perfectly fine, but require an occasional quart of oil.
Stay with what you are doing and don’t go to a higher viscosity oil. The higher viscosity may cause start-up wear and ultimately increase oil consumption.

Run a compression test and this will give you an idea as to whether it may be time to go fishing or cut bait; as in unloading the car.

A compression or leakdown test is not always 100% definitive but it’s all there is when it comes to checking piston rings. You should see readings in the 180 PSI range or better if the engine is in good shape.

Depending on various factors it’s also possible that the oil change intervals are too far in between. Short hops, city driving, environmental conditions, and so on can lead to oil sludging or oil coking problems and this means oil consumption problems.

Many car makers claim that a quart per 1000 miles is normal but I disagree with that.
The car makers have a vested interest in making that kind of claim because to admit its a problem would not only be a bad PR move but could lead to much squabbling and expense over warranty engine repairs.

I agree with ok4450 that a quart per 1000 miles is too much. I don’t like to add oil to an engine between changes. However, the OP’s Dodge is 4 years old and the consumption is 1 quart every 3000 miles. If everything else in the car is o.k., and the problem isn’t in the PCV system, I’m not certain that I would go to the expense of a compression test. Even if it did indicate worn rings, the OP can buy a lot of oil for the price of a newer car if it only consumes a quart every 3000 miles. I would keep checking the oil and if the oil consumption does drop to one quart per 1000 miles, then I would do the compression test and make a decision.
I like an engine to be perfect. However, cheapskate that I am, I’ll put up with a few imperfections if correcting them cost money. I have a push mower that I bought at the beginning of the mowing season in 1992. When the engine was using so much oil that it was fouling the spark plug, I rebuilt the engine with a short block (the mower has a cast aluminum deck with a great design that is good for mulching leaves and grass). After 5 seasons with the new block, I have to add oil after every four hours of use. Putting in a half pint of oil every 4 hours is cheaper than correcting the problem again.

I’ve come to the conclusion that I really don’t have a vehicle problem. I have a vehicle that does too much small town driving, too little highway driving, and I expect perfection in every Chrysler product I drive. You all have helped me put this in perspective - Thank you very much!

A quart every 3000 miles is NOTHING…Half the cars on the road burn this much or MORE and it’s just normal oil consumption…Engines NEED to burn a little oil…That’s what keeps the compression rings and valve stems lubricated…Some cars burn more than others…meaningless comparisons…