shaun12

So i use Royal Purple. i know ford recommends 5w20, but all i can find around my parts is 5w30. does it really make that much of a difference?...or should i really be using 5w20?

i live in MD if that helps.

jagsfan

The 5W represents the lower temperature range of the oil. In this case 5W maintains its' viscosity dow to -20 degrees F. The SAE table shows the 30 (you have 20) goes up to 32 degrees F so the 5W-20 is mainly a winter weight oil. For the spring and summer you are better off using 10W-30 at it range if from 0 to 110 degrees F. This is what I have in my stang now.

Hope I didn't confuse you.

Jag

MineralGrey

^ couldn't have said it better myself, although I still use 5w-20/30 all year long.

02TorchRedGT

I brought this question up to the dealer and they say that the parts in these motors have such small clearances they require 5-20 and using any other weight oil can void your warranty....don't know how true that is...but i would go with what the dealer reccommends in the owners manual.

mikemc04gt

I doubt the difference in 5w20 vs. 5w30 at operating temps is enough to harm these engines, especially considering the 4.6/5.4 were originally engineered using 5w30. I just use Motorcraft 5w20. It protects the engine well ( I have a third party lab used oil analysis to prove that ).

mikemc04gt

One more thing...if you use what Ford recommends and log your oil changes and keep receipts, that makes itabout impossible for them to deny a warranty claim for lack of maintenence.

cliffyk

[/align][/align]This is partly correct. The two "weight" numbers assigned to multigrade motor oils represent theSAE singlegrade number ofthe way oil behaves atspecified temperature extremes. The W designator indicates a "Winter"rating.[/align][/align]The first number indicates the similarity of the oil to single grade oil at a specific low temperature that varies by weight (-30°C[-22°F] for the 5W cranking specification). The second number representsthecomparable single grade weightwhen the multigrade oil is at 100°C (212°F).[/align][/align]So, 5W30 oil behaves like 5W weight single grade at -22°F and like 30 weight single grade oil at 212°F (more or less, SAE gradings are all approximate categorisationsofan oil's characteristics). [/align][/align]It is well established that SAE 30 weight oil provides the best level of protection for a hot normally loaded gasoline engine. However using 20 weight can achieve increases in fuel economy of 1% to 3%, at the expense of increased engine wear--to the point that an engine operated (under normal conditions) on SAE 5W20 oil will at 70k miles have suffered wear comparable to that of an engine with 100k on it that has been running 5W30 oil.[/align][/align]The automakers known this, however that little increase in CAFE (Corporate Average Fuel Economy) saves them a bunch of money in Federal fines (they don't actually have to meet the CAFE standards, they just have to pay a graduated fine if they don't).[/align][/align]Also as they only warranty the power train for 60k miles (used to be 36k), and most buyers don't keepthem that long anyway, they really don't give a rat's backend.[/align][/align]I apologise for the rant, however this whole recommended oil thing keeps popping up. [/align][/align]For normal service duty use:[/align][ul][*]IfI lived somewhere in most of Alaskaor Northern Canada I'd use 0W20(because the engine will likely never get up to full operating temperature), this is the only region where I'd use 20 weight motor oil;[*]If inthe Northen 3/4s of the continental US I'd run 5W30 year round;[*]If intheSouthern1/4 of the US it would be10W30 year round (which is what I use here in Saint Augustine FL),although if I lived in Southern Florida, Death Valley, Mexico, or the hat-*** sections of Texas I'd probably run 20W50 in the summer;[/ul]
There it is...[/align][/align][/align][/align][/align][/align]