When looking at oil viscosity numbers the second set of numbers are the most important because that is how the oil is going to behave at operating temperatures. The first 5W or 10W number is just an indicator of the oil’s cold flow characteristics. The “W” actually stands for winter and not weight.
The second number is a 30, so that is how the oil behaves at operating temperatures. A 5W-30, 10W-30 and a straight 30, will all be behaving as a 30 weight oil at operating temps, but the 5W as better cold flow at cold temperatures, than the 10W, which has better cold flow than the straight 30.
Since all oils thicken when they cool and thin when they get hot, the 5W-30 simply thickens less than the 10W-30 as it cools overnight in the driveway, assuming your region gets temperatures cold enough for the difference to ever show up. Yet when they all heat up to operating temps when going down the road, they are virtually the same 30 weight viscosity.
In many of the Southern states of the USA you can use a 10W-30 and a 5W-30 interchangeably, however in most of the Northern half of the US it does get cold enough to justify the use of the better cold flow that a 5W-30 has. A 10W-30 has no advantage over a 5W-30, so there is nothing to actually gain by switching away from the 5W-30, if that is what you have been using.
For your 1999 Ford Expedition we recommend the following:
Engine: Royal Purple SAE 5W-30 (part #01530, quart bottle) or Royal Purple SAE 5W-20 (part #01520, quart bottle) or for a significant upgrade in performance and protection Royal Purple HPS 5W-30 (part #31530, quart bottle) or Royal Purple HPS 5W-20 (part #31520, quart bottle); 6.0 quarts;
Engine Oil Filter: Royal Purple Extended Life Synthetic Oil Filter (part #20-820);(available at most Pep Boys and through many online sellers)
Auto Trans: Royal Purple Max ATF (part #01320, quart bottle);
4R70W- 5.0 quarts- pan drain / 13.9 quarts- dry fill;
4R100- 6.4 quarts- pan drain / 17.0 quarts- dry fill;
Rear Differential: Royal Purple Max Gear 75W-140 (part #01301, quart bottle); 2.85 quarts;
Front Differential: Royal Purple Max Gear 75W-90 (part #01300, quart bottle); 1.8 quarts;
(w/4wd)
Transfer Case: Royal Purple Synchromax (part #01512, quart bottle); 2.0 quarts;
(w/4wd)
Power Steering: Royal Purple Max EZ (part #01326, 12- oz bottle) or Royal Purple Max ATF (part #01320, quart bottle);
For your 1999 Ford Expedition the details of our engine oil and filter drain interval recommendations are listed below.
Gas Engine Oil Drain Intervals:
For engine oil in street driven passenger car/light truck gasoline engines that are mechanically sound, and stock or mildly modified, the interval is up to 12,000 miles or one year, whichever comes first.
Depending on how many times time you have put a high-quality synthetic motor oil in your engine, we recommend you stay with the manufacturer's recommended interval for two oil and filter changes. This is generally 3,000 to 6,000 miles.
If you have done this with another high quality synthetic motor oil, or if you have another car that has very low mileage (new or almost new car), the oil change interval can immediately be extended to 2x to 3x the recommended factory interval up to a very safe extended interval of up to 12,000 miles or 1 year.
When a Royal Purple oil filter is not available for your application we recommend changing the engine oil filter during the extended oil interval using a high-quality filter. If the filter manufacturer gives mileage guidance, feel free to use that. Otherwise, if running the oil to 12,000 miles, change the filter and top off the oil level at 4,000 miles and 8,000 miles. If you run the oil for up to 10,000 miles, a single filter change at 5,000 miles will be sufficient.
With the Royal Purple Extended Life Oil Filter you can go the full 12,000 miles with RP oil, and have far superior filtration while you are doing it.(available at most Pep Boys stores and available through many online sellers)(not currently available in the drop in cartridge style).
If you put less than 6,000 miles a year on your vehicle, we recommend changing engine oil and filter once per year.
Whenever you change the non RP oil filter, but not the oil, be sure to top off the oil level to make up for oil lost with the filter change. Check your fluid level occasionally because all engines will use some oil.
The 'short' initial oil change interval is to ensure that your engine is relatively clean before going to the extended interval. Many conventional oils and lower quality 'synthetics' tend to form deposits inside engines, and in diesels, leave soot build-up. The natural detergent action of Royal Purple's superior quality base oils tend to clean these deposits and dirty up the oil quickly. After the first two oil changes with Royal Purple, the bulk of the gunk should be gone.
Hope this answers the question for someone else.... I had all these questions here are the answers from RP
Enjoy
The second number is a 30, so that is how the oil behaves at operating temperatures. A 5W-30, 10W-30 and a straight 30, will all be behaving as a 30 weight oil at operating temps, but the 5W as better cold flow at cold temperatures, than the 10W, which has better cold flow than the straight 30.
Since all oils thicken when they cool and thin when they get hot, the 5W-30 simply thickens less than the 10W-30 as it cools overnight in the driveway, assuming your region gets temperatures cold enough for the difference to ever show up. Yet when they all heat up to operating temps when going down the road, they are virtually the same 30 weight viscosity.
In many of the Southern states of the USA you can use a 10W-30 and a 5W-30 interchangeably, however in most of the Northern half of the US it does get cold enough to justify the use of the better cold flow that a 5W-30 has. A 10W-30 has no advantage over a 5W-30, so there is nothing to actually gain by switching away from the 5W-30, if that is what you have been using.
For your 1999 Ford Expedition we recommend the following:
Engine: Royal Purple SAE 5W-30 (part #01530, quart bottle) or Royal Purple SAE 5W-20 (part #01520, quart bottle) or for a significant upgrade in performance and protection Royal Purple HPS 5W-30 (part #31530, quart bottle) or Royal Purple HPS 5W-20 (part #31520, quart bottle); 6.0 quarts;
Engine Oil Filter: Royal Purple Extended Life Synthetic Oil Filter (part #20-820);(available at most Pep Boys and through many online sellers)
Auto Trans: Royal Purple Max ATF (part #01320, quart bottle);
4R70W- 5.0 quarts- pan drain / 13.9 quarts- dry fill;
4R100- 6.4 quarts- pan drain / 17.0 quarts- dry fill;
Rear Differential: Royal Purple Max Gear 75W-140 (part #01301, quart bottle); 2.85 quarts;
Front Differential: Royal Purple Max Gear 75W-90 (part #01300, quart bottle); 1.8 quarts;
(w/4wd)
Transfer Case: Royal Purple Synchromax (part #01512, quart bottle); 2.0 quarts;
(w/4wd)
Power Steering: Royal Purple Max EZ (part #01326, 12- oz bottle) or Royal Purple Max ATF (part #01320, quart bottle);
For your 1999 Ford Expedition the details of our engine oil and filter drain interval recommendations are listed below.
Gas Engine Oil Drain Intervals:
For engine oil in street driven passenger car/light truck gasoline engines that are mechanically sound, and stock or mildly modified, the interval is up to 12,000 miles or one year, whichever comes first.
Depending on how many times time you have put a high-quality synthetic motor oil in your engine, we recommend you stay with the manufacturer's recommended interval for two oil and filter changes. This is generally 3,000 to 6,000 miles.
If you have done this with another high quality synthetic motor oil, or if you have another car that has very low mileage (new or almost new car), the oil change interval can immediately be extended to 2x to 3x the recommended factory interval up to a very safe extended interval of up to 12,000 miles or 1 year.
When a Royal Purple oil filter is not available for your application we recommend changing the engine oil filter during the extended oil interval using a high-quality filter. If the filter manufacturer gives mileage guidance, feel free to use that. Otherwise, if running the oil to 12,000 miles, change the filter and top off the oil level at 4,000 miles and 8,000 miles. If you run the oil for up to 10,000 miles, a single filter change at 5,000 miles will be sufficient.
With the Royal Purple Extended Life Oil Filter you can go the full 12,000 miles with RP oil, and have far superior filtration while you are doing it.(available at most Pep Boys stores and available through many online sellers)(not currently available in the drop in cartridge style).
If you put less than 6,000 miles a year on your vehicle, we recommend changing engine oil and filter once per year.
Whenever you change the non RP oil filter, but not the oil, be sure to top off the oil level to make up for oil lost with the filter change. Check your fluid level occasionally because all engines will use some oil.
The 'short' initial oil change interval is to ensure that your engine is relatively clean before going to the extended interval. Many conventional oils and lower quality 'synthetics' tend to form deposits inside engines, and in diesels, leave soot build-up. The natural detergent action of Royal Purple's superior quality base oils tend to clean these deposits and dirty up the oil quickly. After the first two oil changes with Royal Purple, the bulk of the gunk should be gone.
Hope this answers the question for someone else.... I had all these questions here are the answers from RP
Enjoy
