Hey fellas wat kind of oil is good for the heat outside summer is coming soon and it gets to 115 degrees now when the weather is hot is thinner or thicker oil used

 

At one time, the synthetic German made Castrol 0W30 was testing out to be the best for the LT1. That's with actual lab testing of used oil. It's close to a 40W when hot.

 

I run valvoline 10w40 full syn in the summers here it gets to about 105

 

moparman obviously did some meaningful research, his comments were based on ACTUAL TESTING. TYou will find that the vast majority or responses you will get on a forum like this as it relates to oil are 100% marketing driven and they get upset when someone challenges them to DOCUMENT that their choice actually works well when tested with a Used Oil Analysis.
If you want to do meaningful research rather than read unsubstantiated marketing driven opinion then go here.
Bob Is The Oil Guy - Forums powered by UBB.threads™
There is a section where people share the MEASURED results of their used oil, if you go far enough back in the archives there used to be a lot of LT1 guys sharing their results.

 

Same here, German Castrol. Keeps my rockers quieter.

Great when I can get it local, but most times I have to order it online or through my buddies shop. I always keep a case on shelf though.

 

Do you notice any difference, when you ran a different weight oil, like a 10w-30?

 

i run 5w-30 all year round whats recrommended from the factory anyways

 

5w-30 is recommended for CAFE reasons more than anything else, and 1-w-30 is just fine according to the owners manual down to 0F

I don't know if any major synthetic oil players were making 0w-30 back when these engines were built. Regardless based on Used Oil Analysis 0w-30 Castrol Syntec labeled "made in Germany" does very well compared to other oils. It also happens to be very thick for a 30weight oil.

 

The lower "W" number is only applicable to cold starts. 5W flows better at 0*F than 10W, protecting your engine from premature wear at startup in extremely cold weather. GM recommends 5W-30 year round, but will allow 10W if your coldest temp does not go below 0*F.

Once the oil reaches full operating temperature, it doesn't matter whether its a 5W-30 or a 10W-30. At 100*C (212*F) its the last number that matters. Note that the SAE rating allows a wide range of viscosities to be classified as "30". Based on the earlier testing mentioned above, the German Castrol "30" had a viscosity on the high end of the allowable range for 30 weight oil, and Mobil 1 had a viscosity on the low end of the allowable range.

In the end, it's what the used oil analysis shows with regard to wear of bearings. The rest is just a numbers game.