Synthetic or regular oil?

I just got a 08 ltz with 25k on it and cant decide wheather to use synthetic or regular oil. Does anyone know which would be best for a 5.3 engine?

Synthetic. Seems to be the best way to go. I haven't used anything other than synthetic in any of my vehicles in the last 10+ years.

Synthetic for sure.

i used synthetic mobil 1, in mine, i havent had any problems with it.

Amsoil full synthetic.

Synthetic oils have a prolonged life, but also have a greater heat dissipating property which is why I use it in my tranny

B

I run synthetic in all of my toys... I run synthetic in the tahoe, and change it when the oil life Monitor hits 20-30%

If you want to save money on oil changes, then by all means use a good synthetic oil and change it less often. 3,000 mile oil changes are a myth, you can easily go 10,000+ miles up to 25,000 miles with synthetic oils like AMSOIL. You will want to use one the meets GM high performance oil spec GM 4718M. Most synthetics mention GM 4718M in their list of claims; that's the unique spec created by General Motors for Corvette oil. It's a high-temperature requirement that tolerates less oxidation (thickening) and volatility (boil-off). Avoid bargain synthetic oils. Not all synthetic oils are made the same, you get what you pay for.

GM factory fills all Cadillac with synthetic oil meeting GM Spec 4718M. All Corvettes since the 1990's come with synthetic oil and more and more cars are requiring it.

There MAY be a problem using sythetic oil in engines that have the cylinder deactivation feature. Supposidly the mechanism that allows this function also allows oil to drain down overnight, or several hours resulting in a lifter noise and/or startup grinding noise. I know there is a TSB for the lifter noise but it is not related to oil usage.

I have seen a few threads discussing this issue after switching to synthetic and I have also experienced this. After switching back to dino oil the issues stopped. This is just an FYI, I do not have any official documentation or extensive troubleshooting completed to find the cause of the noise.

There is NO truth that oil is the problem, its a defect in the lifter. I have used synthetic oil in my AFM 2008 GMC for over 25,000 miles and no issues. I have over 25 customers with similar engines and no problem.

Also, synthetic oil is a class of oil and within the class of oil just about everyone has an oil of different chemistry. In others words, no 2 brands of synthetic oil are the same.

I have been using mobil 1 synthetic but since I can get 6 qt. of Royal Purple plus a K&N oil filter for $50 i decided to upgrade to Royal Purple