I live in Tampa, so it's pretty hot all year. Can I get away with 10w-30 Mobil 1, or should I go with 5w-30? This is an 03 2.4T.

 

You could use either. Thicker isn't necessarily better. All I am saying is that the engine temperature is a pretty tight range whether it is 70 degrees out or 90. The engine doesn't know the difference.

5/30 is just fine.

 

My manual says to use 10w 30 for the best fuel economyand use something else when it's too hot or too cold.

I just use 10w 30 all seasons since it's in the wide range for my vehicle.

Another vehicle that I have uses 5w30 and it uses 5.5 quarts.
During the summer, I use 5 quarts of 5w30 and 0.5 of 10w30.
But it really does not make much difference.

 

I use synthetic 10-30 year around. Since I reside in the frozen tundra, (upper mid-west) it can get as low as several degrees below zero in the winter and hit 100 in the summer. I prefer Castrol over Mobil but prior the introduction of Castrol I used Mobil 1 for years!

r.

 

I just thought the thinner "cold" number of 5-30 might be better for the turbo until things warmed up.

 

..................been using 10-30 for years in a variety of autos and none "use" oil. The mfg's changed to 5w30 for the corporate fuel mileage ratings. I have a new MX-5 that calls for...........get this...........5w20! I changed immediately to 10w30 and am happy. By the same token, I have a vehicle that uses 20w50 and the new m-3's use 60 weight. BMW doesn't care about corporate fuel mileage and some of the vehicles have to 'gas gussler' tax affixed.

r.

 

Actually that is pretty much a myth. Corporate fuel economy isn't really affected that much overall by using a lower weight oil. You are talking less than 1/2 MPG. The engines today (re: all Toyota, Honda, Ford etc) all use 5/20. Engines are designed with that oil, not 10/30. There is no engineering reason to use it. Clearances and so on are optimized with 5/20. UOA with 5/20 oils are outstanding.

Here is some information on using the wrong oil. This is from a Ford Escape website.

At 100°C, there's a 26% increase in kinematic viscosity between the Motorcraft 5W20 and 5W30. There is a further 28% increase between the 5W30 and 5W40. However, if you go with 5W50, you will be dealing with a whopping 56% increase over 5W30, and 97% increase over 5W20.

Here are some viscosity numbers for various oils.

The Mobil1 5W50 Synthetic:
cSt @ 40ºC: 105
cSt @ 100ºC: 17.3
(http://www.imperialoil.ca/Canada-En...bil_1_5W-50.pdf)

The factory recommended Motorcraft 5W20:
cSt @ 40ºC: 49
cSt @ 100ºC: 8.8
(http://www.fordpowerproducts.com/products.do?item=15)

The factory recommended Motorcraft 5W30 in areas with limited 5W20 availability:
cSt @ 40ºC: 66
cSt @ 100ºC: 11.1
(http://www.fordpowerproducts.com/products.do?item=15)

I can't see any Esso branding on the bottle of Ultron, but I'll assume that's what it is; I think I can slightly make out the words Exxon above the Ultron brand. Incidentally, Esso and Mobil are the same company (different brands of ExxonMobil), and Ultron is the same oil as Mobil Synt S.
cSt @ 40°C: 84
cSt @ 100°C: 14.2
(http://www.essooil.se/Sweden-Swedis...gue_0905_SW.pdf)

 

Well it is all very interesting that you discuss kinematics and especially so from a Ford Escape web site.

We are discussing oil here and the need to only use 20 weight vs 30 weight. The 5-20 oil states on the bottle that it is "energy saving". The corporate fuel economy restrictions that the government placed on the auto companies dictated that they obtain higher fuel economy. The easiest way in the short run was to use a lower viscosity oil. The drag on the reciprocating parts is less, certainly. But the wear on an engine does increase over time and with ambient temperatures of the southern states. You are myopic if you believe that in the past few years that tolerances in the manufacture of engines all of a sudden became 'closer'. That simply is not true! What has occurred is the quality of oil and the advent of synthetic additives. The use of 10-30 oil does increase the drag on the crank and does impair the fuel economy but the longivity of the engine is what is at stake here and the use of 10-30 oil will improve it.

r.

 

That's old school thinking. The reason for the copying of the info form the Ford Escape website was just to show different oils relate to each other in viscosity.
Don't get your skirt in a knot.

Aren't you the guy who also has his trans flushed out with BG fluids instead of JWS 3309?
A thicker oil isn't necessarily better protection. 5/20 is used beyond the reason of fuel economy. It has to do with engine tolerances as well. That's why Toyota, Honda and Ford use it. I think the engines of those three are pretty solid evidence. If you want to get more responses then pose it on www.bobistheoilguy.com
Discussed to death over there. It's not about fuel economy. Read the forum on it over there.

5/30 is great for P2 Volvo's. It's not for fuel economy at all.

 

Well Fred, that is the fun of this forum. We all have an opinion. I certainly do not disagree with your opinion, I do know that I have been driving since 1960 and have had the opportunity to own quite a few autos. I have been a synthetic user since the product was first on the market commonly sold by Mobil. With that said, I find that synthetic 10-30 has worked fine for me with the plethora of autos I have owned. BMW does not subscribe to your theory and they certainly are well known for close tolerances in their engines. At any rate, I do appreciate your opinion and what I have done is express mine with the experience that I have. As to the trans fluid, I believe in the Volvo dealership that I trade at and it is that dealership/mechanic that uses "non Volvo" fluid. I do flush the fluid every two years irrespective of mileage and will continue to allow the dealer to use the fluid of their choice. I have had no problems and discussed the controversy ad nauseam with them to the extent that I became convinced that they knew what they were 'doing'. Since I truly enjoy my old Volvo c70, I will be keeping it for an indefinate period of time. With that said, I will certainly make a posting if in fact my transmission fails...........and eat crow if that is necessary. Thanks for your input and I shall make certain that my skirt does not knot up.

reg