Motor Oils

[Brian Elfert]

This oil discussion is tame compared to what I see on some other forums I frequent. A lot of the vehicles have engines are supposed to use only 40 or 50 weight monograde oil with ash content of 1% or less. They'll argue all day over .85% ash content versus .9% ash content. I'm not aware of any engine that has failed because of .05% difference in ash content. The biggest issue is folks using 15W40 oil instead of 40 weight and wondering why they go through a lot of oil.

My motorhome uses a special ATF in the transmission that costs $10 a quart. It has to be changed every four years at a cost of about $400 for fluid and filters not including any labor costs.

[Chris Barnett]

Wonder what they do with al that used motor oil that we take back to Walmart? After all the long molecular chains are broken, they wouldn't just filter, dewater and repackage and sell to us....would they?

[Brian Elfert]

A lot of used oil is burned for heat. Some service garages get basically all their heat from drain oil. Valvoline is now selling an oil that is 50% recycled oil.

[Gordon Eyre]

My Infinity now has 216,000 miles on it and it has never had to have oil added between changes. I change the oil every 3,000 miles and I have it done at the dealers.

[Chris Barnett]

If one uses a high number (i.e. 40) viscosity single weight oil in engines designed for multi-weight, the engine will not have proper lubrication except perhaps only at a high temperature. The mechanical engineers who designed these engines did so with considertion of lubricity properties and film thickness of the lubricants on the mating surfaces (bearings, rings etc); these properties are variable with temperature, and specific to oil weight. These folks who designed the engines would say it's stupid to use a single high weight oil on a new to moderate aged engine. I doubt another mechanical engineer will say otherwise, unless it's for under the table money . Just wanting to state accurate info lest someone accept idea to use single high weight oil and ruin their engine; it's from the books.

[Brian Elfert]

One should always follow the manufacturer's recommendation for weight of oil.

The specific case I was talking about is the Detroit two stroke diesel engine. It is supposed to use 40W monograde diesel oil. A fair number of two stroke owners are putting in 15W40 diesel oil instead of 40W oil because 40W diesel oil is hard to find. Using 15W40 oil in a Detroit two stroke can cause excessive oil use and reduce the life of the engine.