Originally Posted by BTJ831

I use Schaeffer 5w-20, with Mobil 1 oil filter. 216,000 miles and has never skipped a beat.

Originally Posted by Stangconv

Due for an Oilchange here soon. Want to run a conventional with high detergents to clean it up before I run full syn.

Any really good cleaning oil? Or just run what I can with some sea foam?

Originally Posted by Stangconv

Due for an Oilchange here soon. Want to run a conventional with high detergents to clean it up before I run full syn.

Any really good cleaning oil? Or just run what I can with some sea foam?

Originally Posted by Martian

"Cleaner oil" = any oil that's certified. They all clean, if you're changing them on time or early. Also, not much reason to go synthetic... unless you just want extended OCIs.

Originally Posted by hahanson

At it's very foundation, the fact that a 5W-30 rating (and understand that the numbers represented are ratings, not actual viscosity) on conventional "dino" is based on thin oil which uses viscosity modifiers to raise it to attain the 30 rating, where PAO oil doesn't need these modifiers as it passes both ratings using the heavier base. Why is this important? Because viscosity modifiers shear and wear out, causing the fluid to lose it's effectiveness at normal operating temperatures (generally accepted as being 100C). This if fine if you change oil often before the modifiers wear out.

At the other end of the spectrum, at room temperature (70F/21C) conventional oil does not flow as well as Group III and Group IV, meaning the lubricants take longer to reach critical engine parts during the time most engine wear occurs. Again, the lower the temperature, the greater the difference becomes -- and it's the difference is substantially more than the "hair" difference you suggest. This is especially relevant to this forum because overhead cam (OHC) engines typically require thinner oils to speed lubrication of the overhead cam(s) and valve-train when the engine is first started.

In fact, this is the main failure of conventional "dino" oil (Group II). It can significantly lose flow properties sitting in its bottle over winter in a garage. Low temperature will seperate the wax and paraffins (this is a big part of the "sludge" you often find around the oil filler and inside the cap), causing the fluid to be thicker and substantially decrease its ability to flow and reach critical engine components during startup. What's the "real world" difference?Mobile 1 compared their 5W-30 synthetic oil to a mineral based 10W-30 and a 10W-40 in ice cold conditions. The engine turned over at 152 RPM with the synthetic 5W-30 Mobil 1. The 10W-30 and 10W-40 mineral oils turned over at 45 and 32 RPM respectively. Neither of the latter 2 engines started.

In general, Group III and Group IV are much better than Group II as they retain their lubricating ability for much longer during normal temps, and have substantially better flow rates at room temperature and lower.