so what does everyone seem to be using???

[sniper1]

Pumpability is measured by two laboratory tests that replicate the results of studies over many engine families. These tests evaluated time to **** up cold up through the oil pickup tube, and then time to produce oil pressure at a point near the farthest oil passage (not a nearby location like the oil pressure gauge is usually plumbed into.) So if the oil is satisfactory down to -15C for example, it will for sure be satisfactory at any temperature warmer than that. In other words, the "W" number already accounts for the efficient movement through bearing areas. As long as you don't operate below the temperature for which the oil meets the requirements there is no problem.

One reason diesel oils are different is that with the very long oil drains, the engine combustion contaminants build up over a longer time period. Soot and blowby are tremendously bad actors and do thicken the oil. Therefore diesel oils have large doses of dispersants, which keep the contaminants from thickening the oil and causing unnaturally high oil pressures or damage to filters. You have less chance of popping a filter with diesel oil.

The "W" number and the second number really have to be disconnected. As mentioned previously, you can mix and match these to produce a variety of viscosity grades. Anybody using a 10W30 can absolutely use a 5W30 or 0W30 with only an improvement in starting and no loss in warmed up features. (absent any discussion of additives in the oil.)

Well if everybody agreed with all of your theories and no problems way of thinking, then we all should just be using one weight and grade of oil and there should only be one oil for all the whole internal combustion engine world to use??? I THINK NOT ! But you get an A for effort. Hopefully everybody doesn't agree with you for the sake of their expensive Viper Engines!

 

[Tom F&L GoR]

Well, for many years people did buy Havoline and Ursa diesel engine oils, so I guess they did agree with my theories and didn't have problems. But those were the good old days... Don't have to agree with me, but hopefully you are getting educated.

BTW, the oil that the Dodge engineers used to develop the engine in your Viper doesn't exist anymore. Prior to 1996 the current API designation was API SH; a high zinc-phosphorus, high friction modifier formulation. You cannot buy API SH oil. The current category is API SM and has reduced the phosphorus level from 1200 ppm to 800 ppm, the use of friction modifiers is decreasing, and we know now that the name "synthetic" can either be a "real synthetic" or a highly refined mineral oil. The ILSAC symbol on the front is an "evergreen" symbol, meaning it will not change even though the oil inside does. The way the low temperature properties are measured has also changed since 1996. So somewhere along this timeline you had to choose something other than what the engine was designed around. How do you choose?

 

[sniper1]

Well, for many years people did buy Havoline and Ursa diesel engine oils, so I guess they did agree with my theories and didn't have problems. But those were the good old days... Don't have to agree with me, but hopefully you are getting educated.

BTW, the oil that the Dodge engineers used to develop the engine in your Viper doesn't exist anymore. Prior to 1996 the current API designation was API SH; a high zinc-phosphorus, high friction modifier formulation. You cannot buy API SH oil. The current category is API SM and has reduced the phosphorus level from 1200 ppm to 800 ppm, the use of friction modifiers is decreasing, and we know now that the name "synthetic" can either be a "real synthetic" or a highly refined mineral oil. The ILSAC symbol on the front is an "evergreen" symbol, meaning it will not change even though the oil inside does. The way the low temperature properties are measured has also changed since 1996. So somewhere along this timeline you had to choose something other than what the engine was designed around. How do you choose?

Good question I have to agree,

Read and follow the instructions that came with your really expensive toy (Viper). Something we should always do but don't and learn the hard way,