I have a 2004 Nissan Sentra SER and 2 months ago i started burning oil i only have 60,000 miles on the car and other than the oil the car runs great. any suggestions on what it might be?

To have to replace an Exhaust Converter in less than 10 to
14 years, tells me the vehicle has not run well most of the time
you have owned it

Cylinder misfires,vacuum leaks or rich fuel mixture, ruined it

The trans fluid HAS to be changed every 3 years or 30,000
miles or it WILL Fail, I guarantee you,having once owned a
trans shop

Check the fluid & if you don't have over 60,000 miles on it ,
change it
DO NOT HAVE IT FLUSHED ---just drop the pan---

Have to get the motor running correctly, before you have control
over the shift strategy, also.

The trans take special fluid-- so be careful

Read your Maintenance Manual about CVT Fluid

It should say 60,000 or 30,000 if you tow etc

I would do it every 30 to 40,000 max, on ALL Vehicles
regardless of trans model or fluid type

For now --ALL Nissan's HAVE to use the dealer fluid to be safe

In a couple years the aftermarket will have it & so will Wal.Mart

the only way you lose oil is by burning it or leaking it, if your car blows a lot of blue smoke, then you are burning it {engine rebuild or replace} if there is oil on the ground when you park, then you need to determine where the leak is coming from, pressure wash underneath before taking it to a mechanic, we hate getting under dripping dirty cars. glad to help.

When it losses power have a fuel pump pressure gage hooked up, it may be the pump is badly worn and it is losing pressure after it heats up, have seen this many a time. Also run a fault code test on the engine control computer using an OBD2 code reader.

Every 60,000 miles is enough.

your vehicle may still be under warranty. Call your local dealer and provide your VIN#, warranty is 60months/60,000 mile powertrain warranty, 96months/80,000 mile emissions warranty. I strongly recommend contacting the dealer before your vehicle hits 60,000 miles.

Your car does in fact need a new catalytic converter. And it should also not burn a drop of oil. It can burn oil as it seeps past leaking intake valves and piston rings.

I highly recommend you do not even start the engine again until the exhaust and intake valves have been inspected and replaced as needed, it has a new catalytic converter and a complete tune up.

you can use anything you want
however, 5w30 is advised by Nissan
limitations is that 10w30 will be thicker in the winter and may cause harder starting and/or bearing failure due to lack of oil on start up

but depending on how many miles you already have.... 10w30 should not be a big deal!!!

There was a recall on the Crank Angle Sensor and another recall in which the engine would consume too much oil due to faulty piston rings

Check under the hood and inspect the valve cover gasket. If it's bad it would explain why you don't see any leaks on the ground because it's probably burning off on the manifold. This ticking you're hearing is a lack of lubrication to the rocker arms. Apart from the valve cover gasket, you should get under the car and inspect the oil pan and oil filter for seepage. Best of luck on your problem.
Greg

Did u add oil and attempt to start car? What's it doing? How often did u have to add a quart of oil (in miles)?
It does sound like it was consuming too much oil, but once u run it dry, there is no warantee that will cover it, so manufacturer can't (won't) help u on this. I agree, an engine rebuild would be VERY expensive due to no oil damage, the best thing to do (if the car is in good shape otherwise, trans. good, body good) would be to find a used motor from a scrap yard (must be careful to check mileage and that the 'donor' car wasn't in a bad front end collision which may cause engine problems) or a re-manufactured engine. Any further questions, let me know, sorry for the bad news.