The Stovebolt Site Forums The Shop Area Engine Shop Multi viscosity question

I understand the risk in suddenly introducing a high detergent oil to a 60+ year old engine that has not been freshly re-conned & had it's galleries flushed etc, but why is there a problem with using a multi-viscosity oil? We wouldn't normally use a monograde in a modern engine,for protection reasons,so why in an early engine?

ken 270,

This is my understanding. Just being a multi-grade oil does not necessarily mean it will have a higher detergent rating than a single grade.

There should be no problem using a multi-grade oil in an old engine.

Modern engines are manufactured with tighter tolerances, higher operating temperatures and are mandated to achieve better MPG.

The multi-grade oils were 'invented' to answer all of these requirements.

The early engine simply does not require the more expensive $$$ multi-grade oils.

It is my understanding that the "detergent" in a motor oil will not actually scrub the inside of a dirty old engine. The true purpose of a detergent is to hold dirt, acids and gunk in suspension until they can be drained with the oil during a change.

I have seen posts stating that switching to a detergent oil will plug the oil filter with all this suspended glop.

That's my take on your questions!

Stuart

I've not done a before & after tear down of an engine that switched from non-detergent to detergent oil BUT detergent oil is an excellent hand cleaner (better then dish soap) when your hands are covered with gunk. If it cleans the gunk off of my hands it almost has to clean the gunk from the engine as it circulates.

Tiny, transmission fluid cleans hands real good and is not as "heavy" or hard to clean off.

trans fluid has nasty stuff in it that absorbs through your skin. use hand cleaner.

Thanks Atomarc

I couldn't see that multigrade oils would be a problem but I guess "multigrade" & "detergent" as topics, get thrown in together.

Ken

chester, I do, I prefer the ORiginal GoJo.