For the last couple of oil changes in my 04 V6, I've been running Amsoil. I've noticed some weird sounds when cold, such as the sound like wet shoes on a tile floor. Anyway, I switched to Quaker State Defy and, a few days later, the sound is gone. I was thinking it was a belt slipping but, now, I don't know. Could it have been an oil issue?

 

That's strange. Amsoil has a pretty good rep as far as I know. The sound you describe makes me think that your oil was foaming or the viscosity was too light. What are the weights for the oil you are using? How long have you used Amsoil? Use anything different before?

 

I had just ran it for about 6,000 miles. I was using 5W30 that is recommended from Toyota and by Amsoil. I was using the OEM spec oil and not the higher mileage oil with the extended oil change. Before that, I was just running conventional oil.

 

Is there a reason you switched from conventional? I guess I'm just curious.

 

I've heard you get better fuel economy and less wear on synthetic oil.

 

Less wear on the engine I agree with. I sold a car that only used Mobil 1. The guy who bought it called a couple of months later and was doing the clutch and asked me if the engine had been replaced!
As far the mpg's are concerned, let us know your experience, please.

 

I can't complain about the mileage. 167k miles and was averaging between 27-29 mpg, depending on driving and where I got gas. I'll have to see what it does on the Quaker State.