I recently went to get my oil change at jiffy lube (want to keep a good car history on official records) and my buddy hooked me up with synthetics, its been probably almost 2000 miles and when i start the car after its been off for a while, it sounds kind of like a tick....i was thinking maybe he put in the wrong viscosity oil and the noise is lack of lubrication? any ideas? ive been looking at tsbs and all i found engine related was camshaft and pcv valve noises.....im almost 100 percent its neither. oh yeah 42k miles on my 06 mazda 6 3.0

 

A lot of people notice additional valvetrain noise when switching to synthetics....primarily Mobil1. Synthetics don't seem to have the sound deading quality of conventional oil....you should hear the difference it makes in some motorcycles. The only way he could've put in the wrong viscosity is if your engine requires 5W-30 but he put in 5W-20. Thicker grades like 10W-30 (only thicker at startup) and 10W-40 won't do any harm during summer months. If you find out he put in 5W-20 and your engine isn't spec'd for it...get it out.

If the noise bothers you, switch back. If there was a pre-existing problem in your engine, synthetics won't make it any worse, but the lack of sound insulation provided by the oil may have brought it to light. I'd have to hear the noise to tell you whether or not it's a problem. Mobil1 brought a little valve clatter in my 3.5 Altima and I just ignored it.