BURNING OIL I HAVE A 2003 NISSAN MAXIMA AN ITS BURNING OIL THE CAR WORKS FINE THERE IS NO LEAK , IT DONT EVEN OVER HEAT, AND THE EXHAUST IS CLEAN , ITS BURNING OIL ABOUT EVERY 500 MILES

Place a clean flattened cardboard under your car and see if it's leaking out. If it's not dripping oil, check your radiator for the presence of oil using a dye test kit available at NAPA. If there is a leak coming from under your car, try to determine from where it's dripping. Most common is an oil filter that hasn't been tightened properly or leaking oil sump bolt. A 1/4 turn on the oil filter should stop the leak, if its the sump... a new screw washer for the sump bolt will usually cure that. Check around the sump mounting bolts, if a fresh leak is evident, you will need a new sump gasket, don't try to tighten the existing bolts as it make leak worse! Tighten to torque specs. Otherwise, you are burning it up... exhaust smoke should be dark instead of light gray. White smoke indicates a blown head gasket and the oil is getting into the engine.

check for 1- vacuum leak 2- spark plug gap being widen or spark plug wire shorting to ground due to old age or close to heat source like touching exhaust manifold 3- your coil pack(there might be one of the bad,check for internal resistance) 4- check idle air control make sure there is no carbon build up on pintle 5- finally check your EGR valve,make sure it hold vacuum.also it is clean with no carbon build up on the valve or passage to intake manifold

Could have an oil gasket leaking oil onto something hot.

Exhaust leaks are a bear, i would first start off by checking where the headers meet the motor. broken down gaskets can release exhaust into the engine bay which will make its way into your cab. either way the burning off of oil is not good as exhaust leaks can damage your valve train and it makes for a very expensive endeavor. Tracking down your exhaust leak should be a top priority though!

you probably have a leaking head, water is getting into the oil. if it does not stop, then try some engine seal, and engine honey. if that doesnt work, be prepared for some major work.

piston oil control rings are worn.this is fairly common on these engines with this mileage on them.

You must have a leak under your hood. Find the leak and fix it.

most likely it is the transfer case leaking. known problem on the AWD models. they leak right down on the exhaust and causes the burning smell. have it checked out again.

Rich fuel=black smoke.
Oil burning=blue smoke
Coolant burning=white smoke

The exhaust will make a normal ticking sound when it expands and contracts, again this is normal. When the oil was changed they probably got some oil on the exhaust and it is taking a long time to burn off. If it has been that long and you are still smelling the oil, take it back and have the shop check for leaks from the filter.