What the heck is going on?
 

Hey folks, I'm having a problem with my Cobalt. It all started when I decided to do an oil change. My car is a 2007 LS 2.2L automatic. I decided to switch from conventional to synthetic oil. I did a bunch of research beforehand since I had heard changing can mess your engine up. Mobil has a whole section on their website that basically dispels all of the things saying you can mess your engine up and claims they are myths. So cool, I make the switch. From the first drive after the oil change my car is acting strange. When I get to a stop and then hit the gas to go the RPMs shoot up to 4 or 5,000 before shifting. I'm not sure if it's a coincidence this started after the oil change or not. It seems to have the most problems going from 1st to 2nd gear. I thought it may be some sort of pressure problem so I re-tightened the fuel filter and assured the oil filler cap was on correctly. Still does it. I'm starting to think it might be a transmission problem but I have no idea so I tried a number of things; changed the air filter, cleaned the throttle body, put some Lucas Transmission fix in, changed the Vapor Canister Vent Solenoid since I was getting a CEL. Nothing. Still getting the high RPMs.


Anybody have any idea what might be going on? My next moves are to unhook the battery to reset the computers in case the TCM is out of whack and then maybe try going back to conventional oil.

Engine oil should have absolutely nothing to do with how your transmission/torque converter is functioning so that should be purely coincidence. I'm not familiar with the automatic Cobalt but I assume there is a dipstick that you check the fluid level while the car is running. Have you checked your fluid level? How many miles are on the car?

Check your transmission fluid level, the problem you're describing points to the transmission not the oil change.

No, I might have to take it somewhere and have it checked since I don't have the ability/equipment to jack it up high enough and leveled. The only way to check it is to jack the car up and undo a bolt. If some liquid comes out its full.

​​​The transmission has 188k on it. It doesn't make any noises when shifting and doesn't shift hard when it finally does.

Thanks for the reply.

I will have to take it somewhere and have it done. I did put some Lucas transmission fix in though and it didn't help at all.

You can check the transmission fluid level. It should be just like checking the oil in your engine except you check it after driving around and warmed up, while the engine is running, an the transmission is in park if it is like most automatics. Checking the fluid should be the first step.

Oh well never-mind then. I didn't realize the automatics did the fluid level just like the manuals. Usually automatics have a dipstick.

The autos dont have a dipstick, they have a reservoir to fill but that's it to what I remember from my 07

Yea the auto has a 10 or 11mm plug on the passenger side to check the fill level. The fluid has to be above 105*f but below 180*f to check it. Should have a slow drip when level is correct and up to temp.