Seems to be some confusion about what the oil viscosity ratings means.
5W oil has to pour (flow) down to -30ºC (at least)
That is the rule regardless if the oil is synthetic or dino, regardless if the second number is 20 or 40.
Motorcraft 5w20 has a pour point of -42ºC (-43ºF)
Rotella T synthetic 5w40 has a pour point of -40ºC/F
Not much difference there. There is a big difference at 100ºC (212ºF) that is where the 40 weight comes into play.
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It takes hundreds of nuts to hold a truck together, but it takes only one of them to scatter it all over the highway.
2008 F250, CC, Black, Lariat
Single Rear Wheels (4x2), Long bed,
Torqshift transmission, V-10 - 6.8L
4.10 Limited Slip
My concern is not cold flow but hot flow ability of the heavier oil in a modular motor and specifically with the top end. Maybe this is not really an issue but I have a doubt that a heavy oil could get where is needs to as effectively as a thinner oil.
It seems a 20 or 30 weight oil would provide all the protection needed within the normal working parameters of the engine. I am not sure there is anything to gain by going to a 40 weight and there might even be something to lose.
Just my $0.02.
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Mike
2000 F-250, SC, SB, 4X4, Lariat, 6.8 V10, Auto, 3.73, Ford Racing headers, SCT X3 87 Performance tune by 5 Star Tuning
Seems to be some confusion about what the oil viscosity ratings means.
5W oil has to pour (flow) down to -30ºC (at least)
That is the rule regardless if the oil is synthetic or dino, regardless if the second number is 20 or 40.
Motorcraft 5w20 has a pour point of -42ºC (-43ºF)
Rotella T synthetic 5w40 has a pour point of -40ºC/F
Not much difference there. There is a big difference at 100ºC (212ºF) that is where the 40 weight comes into play.
Its not that cut and dry. The SAE standards cover a range.
For example below are the viscocities of two SAE 10 weight oils at 0 degrees F.(-17.8degC) (Off my Lubriplate chart, think they are dino numbers)
SAE 10 (ISO-32) = 5400
SAE 10 (ISO-46) = 10,000
Notice that is quite a range viscocity wise and both are SAE 10w oils. Notice the ISO number though, the ISO specs are quite abit more precise than SAE specs. So the assumption of any SAE 5W oil acting the same at a given temperature is not true.
My dealer uses valvoline 5w20 and Valvoline filter, I guess it is cheap.
The SAE standard have a minimum and maximum range for an oil to be consdered 20, 30, 40 weight etc.
SAE 20 has a cSt range of 5.60 to 9.29. @ 100ºC or 212ºF
SAE 30 has a cSt range of 9.30 to 12.49. @ 100ºC or 212ºF
So a 30 weight and a 20 weight can be almost identical
Red Line 5w20 cSt 9.1 pour point -45
Castrol Edge 5w30 cSt 9.8 pour point -55
Motorcraft 5w20 cSt 8.8 pour point -44
Rotela 5w40 cSt 15 pour point -40
I dont think using a 5w30 oil would be any problem, I agree that 40 weight probably will not flow as easily or in the same rate at operating temp. There is only one way to find out and that is to try it for a couple of hundred thousand miles.
I would like to use the same oil on all my engines but I will stick with 5W30 and use the Rotella 5w40 for my diesel tractor.
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It takes hundreds of nuts to hold a truck together, but it takes only one of them to scatter it all over the highway.
2008 F250, CC, Black, Lariat
Single Rear Wheels (4x2), Long bed,
Torqshift transmission, V-10 - 6.8L
4.10 Limited Slip
dkf: I see your online so here is the scoop, I talked to our Castrol rep today and he said that Castrol would love to supply motorcraft oil, but that contract belongs to Conico Phillips. I asked why than do Castrol trucks bring in the oil, his reply was that Ford pays verry well, and as Castrol has the contract for all the other oil's in the plant they do it as a courtesy. So there it is, mystery solved! oil in our engines is MC 5 w 20.
I don't consider 5w-30 an issue for the modulars, as they used to spec 5w-30 in them years ago.
Mine is still speced for 5W-30 and that is what I use. I use it for that reason and all my other vechicles use 5W-30 so it reduces what oils I keep around.
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Mike
2000 F-250, SC, SB, 4X4, Lariat, 6.8 V10, Auto, 3.73, Ford Racing headers, SCT X3 87 Performance tune by 5 Star Tuning
dkf: I see your online so here is the scoop, I talked to our Castrol rep today and he said that Castrol would love to supply motorcraft oil, but that contract belongs to Conico Phillips. I asked why than do Castrol trucks bring in the oil, his reply was that Ford pays verry well, and as Castrol has the contract for all the other oil's in the plant they do it as a courtesy. So there it is, mystery solved! oil in our engines is MC 5 w 20.
To the OP it looks like you got your answer. Mustang looks like you did too! Thanks for the insight redwing.
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Mike
2000 F-250, SC, SB, 4X4, Lariat, 6.8 V10, Auto, 3.73, Ford Racing headers, SCT X3 87 Performance tune by 5 Star Tuning
dkf: I see your online so here is the scoop, I talked to our Castrol rep today and he said that Castrol would love to supply motorcraft oil, but that contract belongs to Conico Phillips. I asked why than do Castrol trucks bring in the oil, his reply was that Ford pays verry well, and as Castrol has the contract for all the other oil's in the plant they do it as a courtesy. So there it is, mystery solved! oil in our engines is MC 5 w 20.
Thanks for getting back to us... Nice to have info from the inside, and not outside speculation...
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06 SuperDuty 4x4 extcb 5.4, TorqShift, 4:10.
90 Mustang 9's, 750 HP Windsor. Ultratech Chassis http://www.youtube.com/watch?v=pibt-TVgAx4
41 Plymouth 49 dodge flathead6 elec ign.
Sig Sauer P229 Two tone.
By the way, back to the performance of engine oils with the same ratings, last winter I performed a simple experiment that majorly opened my eyes.
When the overnight temperature was -20, I set a quart of 5W20 dino and 5W20 synthetic out, and tried to pour them the next morning. The synthetic poured quite well. The dino didn't "pour" at all. I'm not saying it didn't move, I'm just saying it didn't "pour".
For me personally, every winter its synthetic, not dino. They can take those specs and stick 'em where the sun don't shine.....
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2005 F350 V10 6spd dually, 15K receiver. No 4WD, no LS, no A/C, no special cab - just a lean mean towing machine!
By the way, back to the performance of engine oils with the same ratings, last winter I performed a simple experiment that majorly opened my eyes.
When the overnight temperature was -20, I set a quart of 5W20 dino and 5W20 synthetic out, and tried to pour them the next morning. The synthetic poured quite well. The dino didn't "pour" at all. I'm not saying it didn't move, I'm just saying it didn't "pour".
For me personally, every winter its synthetic, not dino. They can take those specs and stick 'em where the sun don't shine.....
Exactly! I don't believe that heavy oil will hurt anything after the engine is warm. I have seen more than one ruined by too heavy of oil on cold startup in the sub zero temps. If you think that 5w20 was thick set out a little 15w40.
Cold flow on dino is one reason I switched to synthetic (Mobile 1). The only draw back to synthetic (besides cost) has been higher consumption. All my vechicles have shown an increase. Nothing horriable but it's up compared to dino.
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Mike
2000 F-250, SC, SB, 4X4, Lariat, 6.8 V10, Auto, 3.73, Ford Racing headers, SCT X3 87 Performance tune by 5 Star Tuning
I'm about due for my first oil change... I've read on the forums several folks advising to do the first change a bit early to get out the factory assembly lube and what not. Was going to do it at 1,000mi but I think I'm just a bit over (1,200 maybe). I bought Mobile 1 5-20 since it seems to be about the most comon I see referred to, and the motorcraft filter. I plan on using it from here on out, and stick to a 5,000-7,500 schedule. Sounds reasonable to everyone (well most everyone)?
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09 F-350 V10 4x4 6spd CC/8' ordered 5/26/09 delivered 7/6/09
99 F-150 4x4 Reg/Short bed
78 Big Bronco 4x4 (a work in progress)
84 Tbird (351W project still in dry dock)
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