Changing Oil Viscosity

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TrainTrac

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In recent threads, some members have said that they're using a different an oil with a different viscosity (0W-30, 10W-30, 10W-40, etc.) than the OEM 5W-30 for Gen1 ST's and 5W20 for Gen 2 ST's.



I've been told by some mechanics that it's not a good idea to use a different viscosity, because that could cause serious harm to seals, bearings, and other internal engine components that were designed to run with the OEM viscosity.



Thoughts/Opinions? Or better yet, can anyone present some hard facts supporting or discounting this recommendation?
 
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Changing oil viscosity, in itself, will not harm gaskets or seals. Assuming that you do not run such a high viscosity that the oil pressure gets too high or the oil is so thick that it can't be pumped up during a cold start. The first number gives the effective viscosity when the oil is cold. The lower this number the easier it flows. The second number is the apparent viscosity when the oil is at operating temperature. In colder climates you might want to go with a lower initial viscosity, say a 0 or 5. In warmer climates you might go to a 10W30 from a 5W20. Remember the wider the spread between the first and second numbers, the more chemistry is required to achieve it. Gen I's and Gen II's are basically the same engine. The change to a 20 weight was to achieve better gas mileage.
 
hmm...



could the gen 1 use the 0w-30

i saw that in a mobil and said for fuel mileage... dont kno if it works but did catch my eye...
 
MikeC,



I fully understand what the numbers in the SAE oil viscosity ratings represent. I was thinking that the change to a 20 weight oil was not only for improved MPG, but also because of improvments in the friction-reducing properties of modern oil. Current oils, engineered with today's technology, are probably much better than the standard 10W-40 used 30-40 years ago.



Techs have told me that one of the main reasons to stay with OEM recommendations is that modern engines, designed and engineered with computers and modern techniques, are much more precise machines, with much less allowance for devation from specs.



For what it's worth, I use OEM recommended 5w-30 in my '04 ST. I'm currently using Mobil 1 Truck/SUV formula, but am thinking of switching to Penzoil synthetic, because it's priced a little bit lower than Mobil 1.



I just remembered having a conversation about changing oil viscosity in the past, and thought it would be a good topic of discussion here, where differing opinions abound...:D
 
I use 10-30. Those numbers in your owners manual are very generic. They are meant to cover vehicles anywhere in the country. An engine is going to operate different in Alaska then it will in Texas.
 
I currently have Mobil 1 0w-30 Fuel Economy Formula in my Trac. I will get a used oil analysis after 5000 miles and if it is okay I will run it for the recommended 7500 miles next time. Mobil says the 0w-30 meets the warranty requirements of all manufacturers where 5w-30 or 10w-30 is recommended.

ONLY the '07-'08 4.6 V8 recommends 5w-20. The 4.0 SOHC is I think the only engine that Ford still specs 5w-30 for.

TrainTrac, I ran Mobil 1 Truck & SUV in my old '05 Trac, got a used oil analysis and it was awful. Much much higher wear metals than with regular Mobil 1. Blackstone said I should only run it for 3000 miles. :blink: I'm just sayin'....

I have always gotten good UOA's with Pennzoil Platinum in every vehicle I've used it in.
 
JohnnyO,



Prior to switching to synthetic, all I ever used in my vehicles were Pennzoil products. When I first started using Mobil 1, there weren't many other choices. I'm considering switching because there are now cheaper alternatives.



Then again, I should probably stay with Mobil 1, since I own Exxon-Mobil stock. I'd hate to hurt myself by reducing their "obscene profits"!:lol:
 
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