engine noise and oil?

[DavidD]

As you can see from my sig. I have a 24valver. I have 115,000 mi on it now and it runs great. I tried the amsoil series 3000 5-30 wt. after all the rave about it on the site. Seemed really good especially in the cold like in logan,ut at 15 below. I decide to change it yesterday and had a supply of 15-40 HHD on hand with a fleetgaurd oil filter. Finish the chage and went out to work on the ranch with my wife. We both noticed the truck sounded quieter! Even my wife commented about it. I know that the sounds it makes change with diffent fuel and temperature but this was the only thing that was different that day. Has anyone ever noticed this? any comments? Dave

 

[DocStressor]

I noticed the same thing when I switched between Delvac 1 (5W-40) and 15W-40 Amsoil. But the difference goes away once the engine warms up. I imagine it is just the effect of the different viscosities. Delvac is actually a little thicker at high temperature than the Amsoil. But at startup the 5W oils allow more valve noise.