I have a 2007 TL Type S, 6 speed, great car.

Nothing on the garage floor but it is burning a quart every 300 miles. Tailpipe is black and grimy. Yes, 300 miles, every tank I have to dump a quart in.

Car had 175,000 miles, had the same problem losing oil. The engine had a problem so we replaced it with a 75,000 mile from a total. The problem of losing oil didn't go away when we replaced the motor. I'm assuming the sensors are the originals. There are no codes.

Could the oil be burning in the cylinder and the cat is catching the smoke/spluge?

What do you think?

 

What are the chances you have two engines that burn a quart every 300 miles? Not likely. Something besides the engine itself is amiss here.

 

^Two engines with the exact same problem????????
Next time on cold start have someone start the car while you're standing behind looking at the pipes. Cats will reduce the smoke very quickly.

 

Sounds like it was misdiagnosed in the first place. Does it have a CAI? Oil level, make sure the dipstick didnt get swapped with the wrong one.

Pull the spark plugs, if a cylinder is burning that much oil it will be obvious. A quart every 300 miles would be hard for a converter to hide. I have more ideas but its late

 

You have an oil leak that's not related to the motor! The tailpipes on our cars are fairly grimy due to their flared design catching all the exhaust gasses but if you are burning that much oil you should be seeing smoke. The engine replacement was def. the wrong thing to do.

I'd go to a DIFFERENT repair place and have them check it out. I bet it's probably a bad oil cooler line or something like that.

 

and that much oil has to be going somewhere. Unless the garage floor is clean, try putting down some cardboard, to be certain there are no obvious drips. It is possible that the oil is not leaking (dripping), but being *blown* out during driving. Still, there would be some on the bottom of the engine with that much oil being lost. If the TL has a plastic plate under the engine, remove it, and look carefully for any obvious oil. Or have a mechanic look.

If so the CAT won't last long, so that seems unlikely, since the previous motor was also *leaking* oil.