So my ap1 has been garaged for about a month now and I havent been turning it on routinely (I know my bad, been busy), I replaced the cat with a different used one for smog check and changed the oil. When I started the car and let it warm up, smoke would come out from under the hood. It stopped after awhile and I went to get my smog check, passed and drove it home all the while there was still no smoke coming out. Then I brought my car into the garage and it was smoking again. The car didn't overheat or act funny during the drive. I was blasting the A/C. I went under the car to take off the cat and throw on my test pipe again and I saw that the AC compressor drain pipe was leaking like crazy. Could this be causing that white smoke? Should I worry about the leakage, AC is important to me in cali. Any help?

 

Water comes out of the a/c drain pipe all the time when the a/c is in use, any chance it was dripping on the header or exhaust as it would cause instant steam ?

The only other thing that would cause white smoke would be a coolant leak, and it would have to be hitting the exhaust or something hot, as the coolant wouldn't have been hot enough to cause steam by itself soon after start up. Check the radiator end tanks for any greenish stains or obvious wet spots, older rads can leak at those spots. Coolant leaks have distinctive sweet smells.

 

Good point on the coolant leak idea above. Check the top of your radiator for coolant leaks.