10W30 vs 5W30

[blackcrowe]

I was just wondering if one was better to use than another. Also, if you have a lot of miles (i have 150k) is the 5W30 more prone to leak? I've been using Mobil 1 10W30 for about a year now and have had no leaks. I have heard a lot of people on here say they use the 5W, but i think most of them had newer X's. Anyway, your opinions appreciated.

 

[etc]

I believe 5w30 is used in colder climates because it's thinner.

 

[ipozestu]

Of course 10W is a little heavier. Living in Tampa your fine with the 10W. Ford recommends 5W , but I prefer 10W, I think it tends to coat better than the 5W to the internals.

 

[Critical_Level2]

I use 5W, but that is because from november to march or april we get an average of 30-40 degree weather in PA. Normally 5W for colder climates and 10W for warmer climates.

 

[skipc10]

Ford has made several announcements or bulletins that 5w30 is recommended for all conditions, and suggest it even for older cars that had higher specs initially. They claim their testing says it provides less wear.

This would make sense after seeing how long it takes 10w and 20w to get to the rockers on my 64 1/2 Mustang! In minutes! And running dry on starting is a big cause of wear.

Another reason it may work today is that the 5w today is much better/slicker/pure than before, so it may hold up better, etc. May not be good if you've got a lot of piston slap though

I always thought some sort of external pump, taken from the oil filter port like a cooler, and used as a pre-start pressurizer would be a GREAT idea and sell millions.... Imagine having the oil flowing in your engine before it starts - might make it last almost forever!!

 

[twomedicine]

API

I emailed the Amer. Petrol. Institute this summer about switching from 5w-30 to 10w-30 since I had access to the later and was 100mi-200mi round trip to buying the recommended 5w-30 for my needed change.

They wrote me back saying they couldn't go against Ford's recommendation and also said they'd have a problem with the performance of the 10w-30. They did not go into detail, but I think they might have meant that the tolerances in our vehicles were designed for the 5w, but actually if the oil went through its range while getting hot, on up to 30w, I really don't see why the 10w would not work fine just as long as the start-up temp is not down in the single digits. I believe that car manuf. use the 5w for fuel conservation; 5w doesn't take as much energy to "loosen it up" during cold starts and short trips/ Synthetics are great too because the stuff is right there pumping and flowing well during very cold starts.

I think the fluidity of Mobile 1 is great down to somewhere around -55F in all their different weights. If you are not in the Dakotas, or in West Yellowstone you'll never hit the bottom range. The shear strength of Mobile 1's film (I hope I am explaining this right as it has been a while) is far superior to petrol. based oils so it'll really protect components well over a large range of temps.

As I remember, petrol. based gear lube "channels" when the temps go into the lower 20's. This means until enough internal friction builds within the differential, or other gear boxes using the traditional gear lube, the stuff really doesn't fall back into the gear teeth well. Synthetics on the other hand, I don't think, channel until well into the sub-zero range, like -40F. Stick a bottle of each in your freezer overnight and pull 'em out and shake 'em and see what happens.

I am a firm believer of using Mobile 1 and other synthetics, however, with my wrist pin noisy X I may not waste my $ on the synthetics since the thing may crater out prematurely due to a poor design.

 

[chadb]

well...

Once the engine warms the oil is at the same temp year round. I would go with what ford reccomends on this. As much as I despise them I suspect 5w30 is the best choice in all conditions.

 

[Tony H]

I've used 10-30 on all my cars from new to current.

I'm new to the Ford world but if Castrol 10-30 got me as far as it did on my other rides then it's good enough for the X.
I even use it in my motorcycles, they both have better then 35000 miles on them with no issues.

 

[X~FACTOR]

Originally posted by muncheese
I believe 5w30 is used in colder climates because it's thinner.

Yes. Plus it gives you a little more mpg. I use Castrol GTX 5w30 year round.

 

[chris c]

Originally posted by X~FACTOR
Yes. Plus it gives you a little more mpg. I use Castrol GTX 5w30 year round.

it's only thinner at colder temperatures. once the engine is up to temperature the 5W30 and 10W30 should be around the same viscosity.

the 5W30 will flow better at cold temperatures. i am not sure what temperatures the tests are run at, 0 and 210 celcius maybe?

as the engine begins to warm the oil thins. [actually, just the pumping of the oil itself will cause it to warm but that it a different thread.] as the engine warms the oil begins to thin. once up to temperature the 5W30 thinned to the point of what a SAE 30 oil would be at that said temperature. again, not sure what the temperature they use is, maybe 210 celcius. the 10W30 oil also thins to the viscosity of a SAE 30 oil at same said temperature. the oils should be acting the same at this point.

of course, there are differences in the oils. the 5W30 oil must have a higher % of or different viscosity modifiers to prevent it from thinning out as much as the 10W30 thinned. if that were not the case the 5W30 would have had to thin more than what a SAE 30 oil would be at 210 degrees...

that being stated, you should not realize any fuel consumption changes when switching between 5W30 and 10W30 unless of course your engine run for a hig % of time while not up to operating temperature...

 

[skipc10]

If I remember, the 5 in 5w50 and 5w20 are not really the same. Oil isn't digital, or perfect. The 5w20, when very fresh, will be close to the 5w50 cold, but it quickly goes up as it's used and ages (we pump no oil before it's time... . Also, it changes as temp rises, so at -20 they may be 5w, but at 90 deg what are they? Maybe the 5w50 is 20 by then...

The same goes for the other number. I had it explained to me long ago, so that's all the detail I have. It HAS been born out in what I've used in older engines where bigger ranges seemed useful, and in comparisons, but I didn't use a viscosity cup or anything, just by look and feel they were definitely different when cold - as in 80 deg room temp.