I just put gastrol 10w-40 in? Okay for couple of miles?
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Bullitt Member
Joined: November 20, 2006
Posts: 389
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I just put gastrol 10w-40 in? Okay for couple of miles?
I just changed my oil in my 06 gt and while I was at the store I for some reason thought that saving $15 oil would be a good idea and just bought some Gastrol 10w-40. I got home put it in and then starting looking up some post. Oh well............will it be okay for a couple of thousand miles and then change back to the reccommended oil? thanks Rob
legacy Tms Member
Joined: October 9, 2005
Posts: 2,607
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From: N.E. Ohio
I dont know, but personally I would go back to 5w20 as soon as possible...weather hot enough it might not hurt anything, but from what Ive read these things are fitted extremely tight specifically so they can run 5w20 for better mileage- the reduced clearances wont flow much of the thicker oil. in the winter I'd be afraid to even start it with the thicker oil...
something else- if changing oil, the filter on these sits upright enough you can fill it well over 1/2way before installing it to cut down on the dry run you get after swapping filters- one dry filter start I would imagine to be hundreds of times worse than any normal start- until that filter element gets filled, there will be no pressure at all...
something else- if changing oil, the filter on these sits upright enough you can fill it well over 1/2way before installing it to cut down on the dry run you get after swapping filters- one dry filter start I would imagine to be hundreds of times worse than any normal start- until that filter element gets filled, there will be no pressure at all...
I run 20w-50 and it doesn't seem to effect the oil pressure or VCT.
V6 Member
Joined: October 5, 2005
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It sounds like you put 10w40 mineral oil in, which probably is not a good idea at all. The manual calls for 5w20, part synthetic, which has a much better cold and hot flow rate, smaller molecule size and slightly higher temperature rating. While it may not do any immediate harm, it will reduce the life of the engine as the smaller outer passages will not get the oil flow they were designed for. As the gauges in the Mustang are just fancy idiot lights - not calibrated gauges, it would be impossible to tell if there is a pressure build up.
Cobra Member
Joined: August 2, 2004
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From: West Kelowna, British Columbia
You should use the oil indicated in the owner's manual. I would not put 10w40 in my mustang even if the 10w40 was 10 cents a litre. I don't think your going to hurt anything but you will find if you change back the car will probably be more responsive as the lighter weight oil will move faster throughout the engine.
Banned
Joined: July 5, 2006
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You will wear out your top end
You have to remember that you have extra tight clearances in your engnine and the 3v 4.6 uses variable timing both electronicaly and mechanically with the cams. The 20w oil is designed to flow through the very tight clearances and also hydraulically actuate your cam timing. I have read where people have used the wrong oil and ruined the top ends of their engines. At a minimum you are reducing the lifespan of the valve train. the 10w isn't gonna hurt but when it acts like a 40w you are doing damage.
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Here is what Ford Says About It
Ford Fleet HighlightsCommercial/Rental/Government E-News
May 23, 2006Back to OverviewsWhy 5W20 Oil?
5W-20 oil is a thinner oil with lighter viscosity that creates less drag on the crankshaft, pistons and valvetrain. Additionally, the oil pump can pump thinner oil more easily, improving oil circulation. Any increase in fuel economy may not be noticed by the average motorist. Machined internal engine parts are more precise than the parts of 20 years ago. This means that clearances between moving parts are smaller and more exact. Thinner oil such as 5W-20 can flow more freely through the engine while still filling the spaces. Thicker oil is harder to push through the spaces between the parts. This causes the oil pump to work harder, which in turn increases oil pressure while simultaneously decreasing oil volume. A lack of oil volume results in a decrease of lubrication and cooling, which may decrease engine part life.
The lighter viscosity of 5W-20 oil flows faster at start-up compared to higher viscosity oils, which helps reduce engine wear in critical areas by lubricating parts faster. Valvetrain components at the top of the engine require immediate lubrication at start-up.
Oil additives are not recommended as noted in the owners manual. The American Petroleum Institute (API) certifies that oils such as Motorcraft 5W-20 already contain the necessary additives for friction, detergent, etc... The addition of additives may interfere and react with the additives already present in the certified oil.
May 23, 2006Back to OverviewsWhy 5W20 Oil?
5W-20 oil is a thinner oil with lighter viscosity that creates less drag on the crankshaft, pistons and valvetrain. Additionally, the oil pump can pump thinner oil more easily, improving oil circulation. Any increase in fuel economy may not be noticed by the average motorist. Machined internal engine parts are more precise than the parts of 20 years ago. This means that clearances between moving parts are smaller and more exact. Thinner oil such as 5W-20 can flow more freely through the engine while still filling the spaces. Thicker oil is harder to push through the spaces between the parts. This causes the oil pump to work harder, which in turn increases oil pressure while simultaneously decreasing oil volume. A lack of oil volume results in a decrease of lubrication and cooling, which may decrease engine part life. The lighter viscosity of 5W-20 oil flows faster at start-up compared to higher viscosity oils, which helps reduce engine wear in critical areas by lubricating parts faster. Valvetrain components at the top of the engine require immediate lubrication at start-up.
Oil additives are not recommended as noted in the owners manual. The American Petroleum Institute (API) certifies that oils such as Motorcraft 5W-20 already contain the necessary additives for friction, detergent, etc... The addition of additives may interfere and react with the additives already present in the certified oil.
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Joined: July 5, 2006
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This is what the Oil specialists who set the standards say.
Which Viscosity to Use?
Engine owners often stray from manufacturers' recommendations regarding viscosity of oils. The engine builders dyno-test their engines using a specific viscosity oil, so when you use the viscosity they recommend, you are working with a known result. Going to another viscosity is an experiment. For the sake of efficiency you want to run the lightest grade oil in your engine possible, within limits. We are seeing that trend for newer engines, for which the recommended grade is getting progressively lighter. The common 10W/30 has become a 5W/30, and some manufacturers even recommend 5W/20 oil. On the other hand, we can't see (in oil analysis) where it hurts anything to run heavier 10W/30s or even 10W/40s in modern automotive engines. The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase. The trick is to find the right viscosity for your particular engine, which is why we suggest following the manufacturer's recommendation.
Did you see the part where it says if your oil is too heavy you will make metal in the upper end? (Valve Train Will Die
)
Engine owners often stray from manufacturers' recommendations regarding viscosity of oils. The engine builders dyno-test their engines using a specific viscosity oil, so when you use the viscosity they recommend, you are working with a known result. Going to another viscosity is an experiment. For the sake of efficiency you want to run the lightest grade oil in your engine possible, within limits. We are seeing that trend for newer engines, for which the recommended grade is getting progressively lighter. The common 10W/30 has become a 5W/30, and some manufacturers even recommend 5W/20 oil. On the other hand, we can't see (in oil analysis) where it hurts anything to run heavier 10W/30s or even 10W/40s in modern automotive engines. The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase. The trick is to find the right viscosity for your particular engine, which is why we suggest following the manufacturer's recommendation.
Did you see the part where it says if your oil is too heavy you will make metal in the upper end? (Valve Train Will Die
)
Shelby GT500 Member
Joined: July 1, 2006
Posts: 2,911
Likes: 1
You have to remember that you have extra tight clearances in your engnine and the 3v 4.6 uses variable timing both electronicaly and mechanically with the cams. The 20w oil is designed to flow through the very tight clearances and also hydraulically actuate your cam timing. I have read where people have used the wrong oil and ruined the top ends of their engines. At a minimum you are reducing the lifespan of the valve train. the 10w isn't gonna hurt but when it acts like a 40w you are doing damage.
Cobra Member
Joined: October 15, 2004
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I read awhile back where auto makers went to lighter oil to help them meet the C.A.F.E. ratings. The fuel economy increase is minute but over a full line up of vehicles every little bit helps.
I used to have some good sites bookmarked that discussed this very subject, maybe you could google it.
My opinion is you will be fine with 10w30.
I used to have some good sites bookmarked that discussed this very subject, maybe you could google it.
My opinion is you will be fine with 10w30.
Cobra Member
Joined: October 15, 2004
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Just googled it http://www.smartsynthetics.com/articles/5w20oil.htm
Team Mustang Source
Joined: January 29, 2004
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I have never understood the phenomenon of people wasting so much effort to guess on an oil viscosity and research other options when it clearly says it right on the friggin cap what should be in it. 
Its one thing if you have a custom built motor, but the stock motor with bolt-ons??
Its one thing if you have a custom built motor, but the stock motor with bolt-ons??
Banned
Joined: July 5, 2006
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Propaganda
Just googled it http://www.smartsynthetics.com/articles/5w20oil.htm
That link is propaganda to encourage people to buy an AMSOIL product. I think I would believe them more if they garunteed their product.
I am not saying they should pay for your motor if it failed but hey even a couple hundred bucks behind their product would be more credible. 
Member
Joined: November 10, 2006
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Back when I was a tech at the dealer i always got a kick out of the Lincoln Continentals with the 4.6 that came in with the oil filter sitting in the bumper cover. It was always a different old guy that said "i've run 20w50 in my Lincolns for years". the oil pressure would go sky high and blow the filter right off the front of the motor LOL.
dude really - pay the $15 and buy the right stuff.
dude really - pay the $15 and buy the right stuff.