Grade of Oil

[justn]

Just a quick question about grade of oil. I was wondering if its better to switch to a 10w30 for a vechicle over 210000km, rather than use whats recommended on oil cap which is 5w30. Will be using a synthetic oil.

What do you think of the quaker state synthetic, or should I use a different brand. Any recommendations?

Thanks

[12Ounce]

I use Mobil 1 5w30 ... available at Costco and Sam's. 0w40, or 5w50, is my preference, but I can't buy it cheap enough. My '99 has 210k miles ... I don't see any level drop between 3.5k/4k changes.

I think Quaker State is fine ... used them for a while, and then they stopped marketing syn for awhile ... so I moved back to Mobil. Not sure I want to fool with them anymore.

[justn]

Could you tell me what the 50 means in 5w50, I think correct me if I'm wrong the 5 is the thickness at low temperatures , and the 50 is thickness at high temperatures, to that effect.

[12Ounce]

It's a complicated subject. Here's my oversimplified explanation:

Years ago there were just single-grade oils. You bought a 10w, 20w, .... 50w (etc... increasing numbers = increasing thickness = slower pour rate) to suit the need/temperature. Of course, like most liquids, each of these grades was "thicker" at lower temperatures and "thinner" at higher temperatures.

Thanks to additives and additional refining processes, along came multi-grades. The additives/processes would retard the "thickening" at lower temperatures.

Two temperatures were chosen as "reference temperatures" ... the boiling point and the freezing point of water. (I think).

So if additives are blended to 50w oil just the right way ... the result is an oil that still performs like 50w does at 212 deg F, but also performs like 5w does at 32 deg F.

Results = 5w50.

[I'm sure there are much better (and more accurate) explanations around.]

[wiswind]

I would not use the 10W-30 unless you have an oil consumption problem....
FORD issued a TSB that recommends 5W-20 for all years, including our older ones that list 5W-30 in the owner's manual.
You are still fine using the 5W-30 in the vehicles that call for them, but they recommend 5W-20 for better lubrication and better fuel economy.
The vehicles that call for 5W-20 in the owner's manual should use the 5W-20.

Oil has come a LONG way in the last 20 years.
My '96 3.8L has just over 180K miles on it, calls for 5W-30 (remember the TSB that 5W-20 is recommended) and I have 5W-20 in it.
I do not even worry about oil consumption at all......no need to add between oil changes.

[justn]

Thanks

[DRW1000]

I was certain that Ford switched to recommending 5W20 as a simple way to improve their CAFE numbers. Not 100% sure though.