Losing oil quickly, could it be the rear main seal?

I've been losing oil prior to the oil change and when I noticed I have forgotten what notified me that the oil pressure sensor needed to be replaced. Wasn't an OBDII reader. It was ether oil residue around the area. Because I had no warning for oil pressure on the instrument panel. Also, when I changed the oil, I replaced the gasket for the oil drain plug. When I check the dip stick and wipe it clean to have a clear reading and place to dip stick back to have a reading level. When it came back clean still. I had thought my entire oil had leaked. But after placing some oil in the engine. It read halfway mark. So, the dipstick reads if it's a quart low of the nearly 4 quarts it takes. Still, I am going to place the front portion of the vehicle on jack stands and wipe it down underneath then run the engine and see where I can find the leak source.

Will do, keep you informed.

I have Wednesday and Thursday off. I noticed lately when I accelerate there’s a whistle like noise that I didn’t hear before. Didn’t know if you can send me the vacuum lines diagram for the 2008 Cobalt 2.2 LS manual coupe has over 130,000 miles on it. I will be able to remove the starter and look where the oil pressure sensor is and make sure it's on hand tighten snugged. I changed the oil about two weeks ago. I’ve been checking the oil and only had to add oil to it a couple of days ago. I checked around the engine for no buildup of the engine oil but I haven’t checked underneath the vehicle where the control arms underneath the crossmember bar. Hopefully if its leaking from the seam between the engine and oil pan right by the oil pressure sensor. Will see Wednesday.

So far, the oil isn’t losing as much as when I checked it last two days ago. Today is the day I will be removing the starter out of the way to clean and check for oil leaks as well making sure the oil pressure sensor is snug.

Well, I checked my oil levels lately and not losing anything but what else could I be having liquid dripping from? I bought some transmission fluid and how can I check if my transmission fluid is low? Since I don’t have a tranny fluid dipstick.

I noticed spots on the driver's side underneath the vehicle that it didn’t look like oil but more like brake fluid perhaps. As I was pulling it in the garage I gave it high RPMs as I was going the garage and I noticed the spots underneath but that was when I had highly accelerated. Now that I have the car jacked up and on jack stands going to see where exactly its coming from. Also, will be checking the brake fluid to see if it needs to be topped off.

When I had pushed the acceleration pedal a bit much when going in the garage. As they say, things happen for a reason, that was how I was able to see the drips.

Yes, it smells like transmission fluid.

I believe it is. What do I need to do to replace the seals?

Don’t know how long that’s been missing but explains the loss of fluid I placed in the top for the transmission fluid. What’s plug size replacement?

Thank you very much!

Luckily the check engine light never came on nor did the transmission seize up. Thankful that I only work less than 1.4 miles away from home but I still did the driving around to here and there that was also in a five mile radius.