So I read the article on the Amsoil site... does that mean that 10w30 protects better than the Ford recommended 5w20 because it has better film and sheer?

I mean I would rather protect my engine more than get an extra mile out of my gas tank.

When using any oil, please remember that the bearing numbers are calculated on the total clearance between the bearing and rotating journal surfaces. The higher the viscosity number at a given temperature, the thicker the oil. The recommended Viscosity (thickness) for the V8 is 5W-20, wherein:
5 = the actual thickness at 32F, and is equal to a "5" single viscosity oil at 32F.
W = generally acceptable for Winter driving applications.
20 = the actual thickness at 212F, and is equal to a "20" single viscosity oil at 212F.
DO NOT use a 10W-anything, the oil is too thick when it is freezing. You really should use an oil with a 5W- base number.
Another way to look at it is like this:
= A 5 weight base is required for proper thickness for freezing engine start-up.
- A single-weight straight 5W oil will get really really thin as the temperature increases, so we never use that.
- A 5W-20 oil will get thinner as the temperature increases, and perhaps at marginal levels.
- A 5W-50 oil barely gets thinner at all as the temperature increases. It is almost a flat viscosity curve.
Natural oils have what is called "Index modifiers" added to them to keep the oil from thinning too fast. A natural 5W-20 oil is a base 5 weight oil with synthetic modifiers which keep the oil from thinning too fast as temperatures increase, BUT some synthetic modifiers can break down in hot conditions. Some natural oils rated at 5W-30 can break-down and start to behave like a 5W-20 after just 200 really "hot" miles.
If you use an oil with a higher second number, that is OK, but it will negatively affect your fuel economy. Mechanical resistance is a little higher, because a "50 equivalent" oil at the boiling point is going to be thicker than a "20 equivalent" oil. The advantage of the thicker oil at the boiling point is that if it breaks down a little, you still have a safe operating viscosity, which will prevent a bearing crash. Also, if you modify the engine for more power, an oil like Castrol's Syntec 5W-50 will carry more piston load at full operating temperature.
So why doesn’t Ford recommend a 5W-50? Because Ford will take EVERY ADVANTAGE to get the highest level of fuel economy possible (the Corporate Average Fuel Economy, or CAFE). When we modify our cars for more power, the flatter viscosity curve is a good thing.

Well I'm in Los Angeles... it never freezes here and is hot pretty much year round.

So being that freezing temps aren't something I'm concerned with would a 10w be better than a 5w as it will break down slower under hot temps?

I run Mobil 1 in my current stang and will do so in my new one after the first oil change.

I use 10w30 in my current stang.

I think the 10 base weight Mobile 1 would be safe for 45F and above. What concerns me is if you were to get into an unexpected freezing situtation, the film could separate if it can't get into the bearing fast enough. If you are caught in cold weather, keep the piston pressures low (easy on the throttle).
I really do like this Castrol Sytec 5w-50 and have had fantastic reduction in consuption and engine noise with both my 1988 F350 and my 1998 Explorer.

I'm sorry, but that's the funniest thing I've seen in this thread yet :lol:

I don't know if that's all you need to know about oil. It's from the Amsoil site. Why not link to the Mobil 1 site? Mobil 1 must be pretty good too, seeing how Nascar, IndyCar, and Champ Cars use it in their very expensive engines.

If it were me, I'd rather be safe than sorry, and just drain that oil out now, and replace with the recommended viscosity. Why risk anything with a new $26,000 car over $20 worth of oil? It's a no-brainer to me.

I don't see any websites out there with Mobil 1 claiming they are the best, or any lawsuits against Amsoil saying they are not. Kind of makes you wonder, maybe they are the best?

Actually, Royal Purple was claiming they were the best, and Amsoil filed a lawsuit against them. Royal Purple doesn't claim to be the best anymore, but Amsoil still does. Makes you wonder.... maybe they are.

From my familys experience with Amsoil, I don't have too many issues with them claiming to be the best. I haven't seen any oil that works better than (or even as good as) Amsoil.

Mobil 1 really doesn't need to claim they're the best. The fact that there are Mobil 1 stickers on the bodies of IndyCars, Champ Cars, and Nextel Cup cars, and Mobil 1 inside those expensive engines is all the bragging they need. If that doesn't convince you it's good oil, I'm not sure if anything will.

Overhead Cam motor with Variable Cam Timing . . . use 5w-20. End of story. New engines run very tight tolerances, and are very sensitive to oil pressure. In the summer you might be OK, but in colder months, you're asking for trouble down the road.

Uhm, that is called "sponsership". And it is on every car because they sponser the series (not just a single car). That does not mean they are the best. And no one was saying Moble 1 WASN'T "good" oil. The argument was on which one was "best". So far, Amsoil has been able to maintain that tile and Mobil 1 hasn't. But it does NOT mean Mobil 1 isn't good, or even VERY good oil.

http://neptune.spacebears.com/cars/s.../oil-life.html

Read this link. A real world test between Amsoil and Mobil1. It appears Amsoil thickens too fast and goes out of spec for grade. The article states that Amsoil "is not good for engines that like thinner oil". Also, for me, deposit formation on the back of the valves is important. Mobil1 keeps them spotless...not sure about Amsoil. My brother-in-law runs a motorcycle speed shop and tells me that only the motorcycles that use Mobil1 show no deposits...all others do. I believe the cycle engines run a little hotter so I'm inclined to believe Mobil1 will do excellent in our engines.

Does Mobil 1 sponsor the IndyCar, Nextel Cup, and Champ Car series? And that's the reason it's in their engines? Okay, I didn't know that - I figured the engineers would use the best available equipment and materials when it comes to their engines, so that the engines would last and have a chance to win the races. But I'll take your word for it if sponsorship is the reason that Mobil 1 is used...

I'll just repeat what I said before - if Mobil 1 is good enough for a million dollar race car engine under the most brutal conditions imaginable, then it's good enough for my $26,000 Mustang.

Amsoil may be better if you say so, but I'm not gonna spend twice as much on it when I know that Mobil 1 is good enough for a 15,000 rpm 800-horsepower IndyCar engine.

wjones14,

When you get down to it, comparing oils that are used in race engines for 3 hours and 500 miles (or 2 minutes and 1/4 mile!) to an oil we run in our cars for 7000-15000 miles over the course of a year is just plain silly. The requirements for the oil is completely different (shear strength, low drag, high temp resistance necessary in the racing applications vs. long term viscosity, detergent stability, etc for street use) for these applications.

And don't take anything because "I say so". Do some research. There is plenty of independent research out there that shows how the different oils stack up. Do the reading and make up your own mind. I would ALWAYS be wary of opinions expressed in assorted internet forums (yes, even this forum and even MY views!). Data talks.

you mean everything in this forum isn't necessarily true? :(

What you say is exactly why I responded to this thread in the first place - someone said all you need to know about oil is in this link - and the link pointed to Amsoil's site! so I just figured there was a possibility that the info there might be biased, and asked why there was no link to the Mobil 1 site as well. So folks could make up their own minds.

So, doing my duty as any red-blooded TMS member would do, I hereby provide the link: http://www.mobil1.com

Just because the sticker is on the car or motorcycle, doesn't mean that vehicle uses that product. I have been a roadracer for 5 years, and I've seen dozens of instances where someone used their sponsors stickers (and money), but used another (better) manufacturer's product.

Ok, from that link also:

"We note that initial wear is significantly reduced from the Mobil 1 sample."

"Amsoil's rate of wear metal accumulation is clearly superior to Mobil 1 in most cases."


Also to note, the Mobil 1 couldn't keep the insolubles in check, and required a filter change during the test, that the Amsoil did not.

But yes, the Amsoil did thicken up quicker than the Mobile 1, but I don't plan on leaving my oil in for 18,000 miles either. I'd rather have an oil that prevents wear during a 3000 mile interval, instead of an oil that will maintain it's viscosity better over 15,000 miles.

Mobil 1 is good oil, I'm just not going to say it's the best. Mobil 1 also doesn't claim they are the best, so maybe they are not?

I am so tired of the people that so easily say you can "kiss your warranty goodby" for such simple things. How by the way will ford know he used 10/30 vs 5/20? they wont, and if his whole engine blew up he could do another oil change to 5/20 and no one would know the difference. You'll be fine with the thicker oil, maybe a little less power thats it.
BTW all he is in CALI he doent worry about cold weather

Since I love throwing more gas to the flames....

If you want to use "the best", dont care about emissions as much as you do about getting the most power and long time protection from their 4.6 3v, you should look into Amsoil Series 2000 0w30 as your oil of choice. Synthetic that is.

And btw, Mobile 1 Full Syn is pretty darn good oil and is the same price as Amsoil.

-Dan

For me I'll happily continue to use Mobil 1. Is AMSOil better? Doubtful... but if it is I still have to wonder why I cannot drive to my local Pep Boys and find any on the shelf. Beyond this its not stocked on the shelf at my local Auto Zone, Checker, or Wal-Mart either. Come to think of it I've yet to see AMSOil sitting on the shelf of any major automotive parts retailer in this state. Hmm... I wonder why?