how does 10W get better start-up over 5w?

 

Since its a heavier weight, it saturates the engine more and just starts better.

 

Well Im not an expert here, but we're learning about oil into AutoTech class in school and our instructor tells us lighter oils start better than heavier oils because of lighter viscosity and all.

 

They do. Lighter viscosity oils work their way through the engine faster on a cold startup, thus reducing wear. 5W-20 or 5W-30 oil is a good choice for production engines of today because of tighter engine tolerances and clearances. A thinner weight oil would work best for this situation. And for those who don't know this, an oil's weight rating, (or the number before the "W") is the oil's weight at cold startup. The viscosity rating is the number to the right of the weight rating (ie. 5W-"X"). That number indicates an oil's viscosity when the engine reaches full operating temperature.

 

I always had great luck running Pennzoil 5w-20.

I put 126k (trouble free) on my F150 4.2 before selling it a couple weeks ago.

 

Yeah, thats cool. I just learned this like a few days ago. This is the reason I'm going to be switching from Penzoil 5W-30 to Mobile 1 5W-20 Synthetic on my next oil change (996 miles and counting...)

 

Smart move. You did right by starting out with a regular dino oil like penzoil though. Using Dino oil as a break-in oil, and then switching to synthetic is a common practice. During the first 3000 miles, regular dino oil allows your piston rings to seat better and all that good stuff. Once your engine is broken in, switch to synthetic (or semi-synthetic) and never look back. Oh, and remember once you switch to synthetic, it's not a good idea to switch back to dino oil. It can spin a bearing or something worse. Hope that helps.

 

I just had really good luck though on the quaker state horsepower 10w30 Full synthetic. I just felt a big change in my performance with the 10w30 ,i used to use mobile 1 5w30 and worked good but the quaker state horsepower changed my mind.Thats just my opinion.

 

I just wasted $35.00 on the Crap fully synthetic high milage 5W20 made by O'Riely's. Put it in with a new oil filter and my oil presure dropped and the oil guage went nuts. Dumped that crap back in the jugs and took it back to O'Riely's and left it out front for them. Went to another store and got traditional 10W30 and another new filter. Did the oil change again only 3 days leter after the other oil change. Now i have oil presure again and guage is back to a slight wobble. Almost blew my 4.2 L moto with their crap oil. traditional 10W30 from now on no mater what the manufacturer says or recomends unless they want to buy me a new motor.

 

I bought my 4.2 with 65k on it, it now has 199k. All I have ever used is 5W20 Mobil 1 EP and a Mobil 1 filter in it, I have no oil pressure or consumption issues.

 

I've had two 4.2l v6's and both have used MC 5W20 just fine with MC Filters... my truck is still under warranty, and even after, I'll still use it.

Also, the price of MC oil and filters is rock bottom most of the time.