Multi-viscosity oils

X-Y switch · May 8, 2019

Have always wondered if those multi-viscosity oils were really what they are marketed to be. All vehicles and tractors I have ever owned using these oils always have much more oil pressure cold than at operating temperature. Welcome your comments, Harry

old · May 8, 2019

Any oil be it a 30W or a 20W-50 will have higher oil pressure when cold then when hot. Oil thins as it warms so all oil pressures will be lower when warmed up

rustred · May 9, 2019

if the engine is in good shape with the brgs. and pump in spec. then there should be little noticeable drop in pressure when hot.

4wdtom · May 9, 2019

I have seen a flathead V8 ford and a couple of Allis Chalmers tractors (which don't have a lot of oil pressure anyway) run with no oil pressure when warm. They were so
loose no pressure could build up but oil was still flowing and probably the crankcase was a thick cloud of oil flung out of the bearings. All of these engines had a LOT
of hours and ran for a LOT of hours in this condition. As long as they had oil flow and didn't knock too much all was good.

fastfarmall · May 13, 2019

There's a interesting video on you tube about oil viscosity,they have maybe 8 different tubes, with differant weight oil in each tube,and it's in a temperture controlled lab,then they tip em all at that same time, and you can see which comes out at differant flow rates ! But i am with rustred if the engine is in good shape it's not going to drop much!

Multi-viscosity oils

X-Y switch

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old

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fastfarmall

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