Originally Posted by Navi
Please dont troll the thread with a speech about not suggested lubricants. Even though in the owners manual it says to use such&such weight lubricant in the USA...in places like the Middle East, Alaska, Australia the suggested weights are different in the owners manual or known to the people there. For example 20W50 seems used a lot in places like Dubai and 5W40 used a lot in Europe. People in those geographies know what they need.
5W30 is usually suggested in the USA as a catch all general lubricant for Suburban commuters experiencing 4 season weather. Maryland comes to mind.
My driving is all severe service putting 70000 hard miles a year on them. Thus Ive settled on 5W40 and have had zero issues. Blackstone gives it a glowing report every time. I dont do long drain intervals. The best way to keep an engine free of things like sludge is frequent oil changes. In fact before the present day maintenance meter manufacturers like Ford said 5000 miles per change for police cars and severe service vehicles.
Oil is cheap but an engine is 5 to 10k dollars. Thus I feel its better to be safe then sorry so I change before 5000 miles. This is how I make a living and I dont take chances.
Funny the only trolling I see is from you attempting to "fix" a problem with a lubricant. News flash this is the United States not the various countries you mentioned plus you don't operate your Navigator in stated countries. Ford tested this design with a 5W30 not whatever you feel like using. Dubai is a desert with a lot of WOT runs without warming an engine up its start and go. It's not New York with significant idling you are not researching a thing on your engine. You are playing Ena, mena, mona, mite and then doing a UOA. Far from any engine testing.
Did you consider this while making a choice?
https://www.infineuminsight.com/en-gb/articles/passenger-cars/timing-chain-wear/
How do you know your chosen formulation was subject to a timing chain wear test since it did not undergo ISLAC testing? Improper viscosity and using a lubricant longer than designed causes timing chain wear. Since the ISLAC testing was completed by the blender and manufacturer on a 30 grade how can you doing a UOA determine you are using the optimal lubricant? Will using a 40 grade do no harm? Likely no. Will using a 40 grade be any actual benefit? Likely no. Being said it is far more prudent to use what the OEM and it's suppliers have tested and recommend in a known problem child than playing rouge lubricant cowboy based on UOA.