My speed is sitting at the dealership again right now for smoking exhaust. I have 58,000 on it now and have had the issue again for about 10,000 miles. I had my turbo replaced under warranty by the dealer last summer at around 35,000. Unfortunately the issue has come back and now they want to test the seal by adding 5w-40 oil and seeing if it smokes. Otherwise evidently Mazda is developing a new pcv valve that will bleed off more pressure from the crankcase I am told. Either way it looks like they are screwing me because they want maintanence records again and I cant find them so... Perhaps I will be trying one of the fixes proposed above. Pretty sick of this car. Broken motor mounts, smoking turbos, chipping paint disconnected rear swaybar etc. Junk.
