2.25 oil pressure at idle

GETTING THE BEST 20W-50 OIL FOR YOUR VEHICLE

Whether you choose high mileage 20W-50 or conventional 20W-50 motor oil, they will both flow like a 20 Weight oil in cold weather, then with the viscosity of a 50 Weight oil once the engine is up to full temperature. Choose Castrol® GTX® 20W-50 to protect against sludge and Castrol® GTX® High Mileage for older vehicles with over 75,000 miles on the odometer.


The above is an excerpt from the CASTROL site I explained it wrongly when I said it is 20 weight at start and gets thicker when hot I was trying to explain why we use it in our engines to aid in cold starting but with sufficient viscosity to protect our engines in our hotter climate.

Gippy👍

Quote:

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Originally Posted by WhatIsClocks

That lines up with my personal experience the few times I've drained hot oil - it's definitely thinner. Thought I was going crazy reading everything on the internet saying it was thinner when cold.

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20W 50 is the same viscosity as a 20 weight would be at low temperature and the same viscosity as a 50 weight would be at higher temperatures.
It thins but not as much as a straight 20 weight would at higher temperatures.

Colin