Mixing 5W-30 & 5W-20 in Ford Ranger 4.0?

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I have a small stash of 5W-20 PP from a previous auto and would like an opinion on using it up my 2000 Ford Ranger (only 46K) mixed with PP 5W-30 approx half and half? Will that make it too thin for the 4.0 engine? The vehicle is now my main transportation but still doesn't get a lot of miles put on it as I ride the Can Am a lot. Motor seems in excellent cond, uses no oil. I should note that the truck sat for many years with only 1,000 miles or so per year but the oil was changed yearly using dino. Now that I have begun using it more, I'm thinking of going with synthetic. The oil was recently changed with Mobil 5000 & MC filter so its won't need changing till spring.
 
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IIRC the Ford 4.0L engine was not back spec'd to a 20 grade oil. I would not use a 50/50 mix. If you want to get rid of the small stash either return it or use it up in your 4.0 engine one qt/oil change. I'm sure plenty of members will tell you its fine, I'd probably return it, or use it in something calling for a 20 grade oil. You could probably get away using it one qt at a time mixed in with the 5W30.
 
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I know relatively nothing but I personally would use 5w-30. Mobil 5000 is very good oil. I have quite a few jugs of Havoline 5w-30 conventional oil waiting to be used. Enjoy your truck!
 
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Have a 2002 explorer. 20 weight not recommended by Ford. However, I did run GTX 20 weight (a heavier 20) for 5000 miles with no ill effects and didn't really notice a difference. I'd just get some Pennzoil, Shell, or Quaker State 10w-40 and mix it 60% 5w-20 and 40% 10w-40 and you'll be about right in the middle of 30 weight.
 
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Most 20-weights cluster in the top 1/3 of the viscosity range, so doing a 50/50 blend with 5w30 would get you a borderline 30-weight. I agree with tstep's suggestion about doing a blend with a SOPUS 10w40.
 
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Use the 5W-20 as top off - or mix 1 qt in with the 5W-30 as a "winter blend". It won't go bad sitting in the bottle while you're slowly using it up.
 
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Like others have stated, there are several better options. If they are still sealed and current, exchange the 5w20 for 5w30 at Walmart. They won't bat an eye. If you can't, then I would do what bigt61 says. I wouldn't do a 50/50. Ford didn't back spec it for a reason. Maybe mix 1 with 4.
 
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You could also use a quart or two of the 20-weight oil in the winter months to form a lighter viscosity 5W-30.
 

OVERKILL

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Originally Posted By: Propflux01
It's my understanding here that most all 5w-30's shear to a 20W anyhow. The PP will be pretty stable anyhow. I'd use it as planned.
That's a gross generalization and I think if you looked at the 5w-30 UOA's you'd see that there are indeed some that shear but certainly not "most all" of them. If a particular engine is hard on an oil and has a propensity to shear it, it is going to shear anything with VII's, including 5w-20.
 
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I had an Explorer with the OHV 4.0, and was interested in the back-spec testing. The 4.0 wouldn't pass the durability tests using 5w20. I don't remember exactly, but it was something in the timing chain area. I assume the tests were done using Motorcraft oil, which is a syn blend. I'm sure it stayed in grade. Your call, but Ford tried to back-spec since there were so many 4.0's around and they could have gotten a big fuel mileage credit from EPA. When the manufacturer says it won't work, I would listen to them.
 

tc1446

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Thanks folks for all the information. It never occurred to me to return it to Walmart but I did get it there and will take it back and exchange it for correct weight for the Ford. The truck doesn't use any oil so it would never get used up that way and since it isn't driven much, I'd never use it up a quart at a time. With the DI on the Accord, I'd rather stick to a 0-20 and just bought 2 jugs PP during the $10 rebate, plus i have one jug of M1 0-20 on hand.
 
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Originally Posted By: A_Harman
Most 20-weights cluster in the top 1/3 of the viscosity range, so doing a 50/50 blend with 5w30 would get you a borderline 30-weight.
Most 20 grades may cluster at the top of the kinematic range but more importantly their all at the bottom in terms of their HTHSVs. Nevertheless a 50/50 blend will still give you an oil that's as close to a light 5W-30 that makes little difference. Of course if you had an oil pressure gauge then you'd know but since we're entering the coolest time of the year I wouldn't be concerned that you're suggested blended is too light.
 
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It'll upset the additive package and create the wrong viscosity oil, but it's your engine. The mineral oil was probably the perfect oil for that type of use as it adheres to the engine better which protects against corrosion on sporadically used machines.
 
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Originally Posted By: CATERHAM
Originally Posted By: A_Harman
Most 20-weights cluster in the top 1/3 of the viscosity range, so doing a 50/50 blend with 5w30 would get you a borderline 30-weight.
Most 20 grades may cluster at the top of the kinematic range but more importantly their all at the bottom in terms of their HTHSVs.
Interesting observations both of you, which would indicate that the grade is based on a high degree of temporary shear, which is indicative of VII (polymer) action rather than inherently high VI base-stocks.
 
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