m1 0w40 to m1 0w20ep switch in 99 4.6 ford

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After the switch to 0w20ep the engine is quicker but also slightly noisier after warmup. Startups have a little more juice with 0w20 but both weights are nearly identical (smooth with no wierd noises).I have owned the 1999 expedition since new and it has had only mobil 1 after the factory fill drain. It used to get m1 5w30 upto 100k miles. Since then it has had mostly 0w40. On one long trip from chicago to miami in 90 plus heat i have used 0w30 afe with good results too. The expy sees a lot of long trips 12 hrs a day at 70 plus mph. It has burned a quart of oilevery 700 miles or so from day 1 smile (1999). After reading a lot regarding how ford modulars love mc 5w20 and great base stock of m1 0w20 ep i decided to switch for the winter to see how it performs. Now thinking that i made a mistake in switching i went through all reviews on mobil web site and found quite a few ford modulars that have made it past 250k miles on 5w30 despite ford tsb to switch to 5w20. I have never had any problems either with the heavier weight oil. Once on a gruelling drive from ca to illinois i have used m1 15w50 as top off oil during the drive with no ill effects. By the way i filled with 6 quarts as told by owners manual. I have done this since 1999. Never bothered to check it after that. Well this time i drove for 30 miles and decided to see if there was any burnoff with lighter 0w20. The dipstick was halfway between add and full mark. I was like wow half a quart burned off in 30 miles with 0w20 smile After internet search i saw that to get the level to full it takes 6.5 quarts. Learn something new everyday (embarrasing too). Does anyone know what is the optimum oil pressure for the chain guide tensioners (too much and they wear out and too little is not good also:) Also molecule size in 0w20 is smaller than 15w50. What happens when you mix them. Do they become one size or they retain their sizes which could result in small ones going in tight spaces and big ones going where space allows. Kinda a like best of both worlds. I am thinking of draining 1 quart of 0w20 and replacing it with 15w50 to see the effects on engine noise and power. Hoping to somehow end up with an optimum mix lol. 2.5w25.
 
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I'd probably run AFE 0W30 and call it a day. I wouldn't be mixing oils trying to achieve an optimal 2.5w25 blend which doesn't exist.
 
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Originally Posted By: merconvvv
Also molecule size in 0w20 is smaller than 15w50.
"Molecule size" of what? The base oil? The different hydrocarbon additives? The anti-wear additives? The EP additives? The detergent additives? The VMs? The pour-point depressants? Its naive to say that "molecule size" differs between two oils, when there are hundreds if not thousands of different molecule types that make up both of the oils, and those molecules come in hundreds if not thousands of different sizes. Viscosity depends more on how the molecules interact with each other than on how "big" the molecules are.
 

merconvvv

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Obviously the molecule size of whatever protects the engine at 100c by finding its way into tight spaces. Polymers and base oil would be a start.
 
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Originally Posted By: ARCOgraphite
40 to 20 is too drastic, dude
You think the bearings are going to fall out of the rods because they were used to 40 wt for a little while? The engine doesn't care. OP: Check your levels with the 0w20 and don't drain a quart or try to make your own blend. Just keep an eye on the level and if it doesn't work out you can always go back.
 
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Originally Posted By: merconvvv
Obviously the molecule size of whatever protects the engine at 100c by finding its way into tight spaces. Polymers and base oil would be a start.
Molecule size doesn't matter at all when it comes to getting into tight spaces. You can fit 1,000 or more oil/polymer molecules across 1 micron. We see crankshaft roundness tolerances are currently at 3 microns (at best in 2016), and surface asperities can be as little as 1 micron sized mountains. I'd use the cheapest 5w-30 SN GF-5 conventional I could find in that old Ford burning a quart every 700 miles, and then only change the oil filter (Fram Ultra please) every 10,000 miles, never changing the oil since it loses so much all the friggin' time.
 

OVERKILL

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Originally Posted By: 901Memphis
You can make a custom blend with some Toyota 0w20 and Castrol 0w40
Why would you want to? You'd be diluting a majority PAO-based Euro oil with higher levels of AW additives with a Group III GF-5 energy conserving product. They aren't even remotely similar.
 

SR5

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Hey OP, so you started on M1 5W30 to 100k miles. Then moved to M1 0W40 for awhile, then decided to give M1 0W20 a run. And apart from the 0W20 starting a little nicer, and the 0W40 being a little quieter, they all work fine. This is what I would expect. Most oil works in most cars, with only small differences. Good on you for having the balls to go from a 40 grade to a 20 grade. You know it's OK because it was back specced. The big jump allowed you to see the small differences better. Yes you can mix oils, many do, but I prefer a completed and balanced product from the manufacturer. I would split the difference and use your original M1 5W30 and call it a day. Unless you enjoy experimenting, in which case, fill 'ya boots and have fun. All commercial Multigrade oils sold are a mixture of various high and low viscosity bright stock (base) oils, with various molecular sizes. So mixing two finished products, like a 5W20 and a 0W40, is just mixing two mixtures together. Sure it will work, but nothing magic will happen. They are already blended at the factory to perform well in the field.
 

merconvvv

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Oh i forgot to mention that cat converter is more alive with 0w20. With 0w40 i would not hear popping noises from underneath after i shut off and get out ! 0W40 had much less and only after long highway trip on summer day. Of course the engine noise i memtioned earlier was not this noise.
 
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Originally Posted By: merconvvv
Oh i forgot to mention that cat converter is more alive with 0w20. With 0w40 i would not hear popping noises from underneath after i shut off and get out ! 0W40 had much less and only after long highway trip on summer day. Of course the engine noise i memtioned earlier was not this noise.
Wow that is some oil. Do the windshield wipers work better too?
 

merconvvv

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Yes the windshield wipers have now additional functions such as auto sensing rain and adjusting speed accordingly... Thanks 0w20ep:) the cat conv. might be more alive due to temp increase but have not noticed any difference in temp on guage.
 
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I have had good luck blending 4:5 TGMO 0w20:Mobil 1 0w40 FS. This will give you a nice 0w30 with a much higher VI than Mobil 1 AFE 0W30 and a nice high TBN and SAPS for extended drain intervals. Credit to Caterham for the recipe.
 
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Originally Posted By: merconvvv
Oh i forgot to mention that cat converter is more alive with 0w20. With 0w40 i would not hear popping noises from underneath after i shut off and get out ! 0W40 had much less and only after long highway trip on summer day. Of course the engine noise i memtioned earlier was not this noise.
Between this nonsense and "molecule size" theories, this thread is officially in the ditch.
 

Nick1994

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Originally Posted By: demarpaint
I'd probably run AFE 0W30 and call it a day. I wouldn't be mixing oils trying to achieve an optimal 2.5w25 blend which doesn't exist.
+1
 
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Originally Posted By: micmac
I have had good luck blending 4:5 TGMO 0w20:Mobil 1 0w40 FS. This will give you a nice 0w30 with a much higher VI than Mobil 1 AFE 0W30 and a nice high TBN and SAPS for extended drain intervals. Credit to Caterham for the recipe.
He's only guessing that it's a 0W30... When you start mixing (it's not "blending", that's what oil blenders do, it's "mixing" two finished oils), you don't know what the "W" rating does...heck, you don't even know what performance tests the new mix may/may not meet.
 
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