multi-weight vs. straight weight

Messages
2,688
Location
Elderly County, Florida
Howdy fellow oilers. I live in Central Florida, so cold winter issues are not a problem with me. Therefore, should I still be running a multi-weight motor oil in "Big Red," or can I run a straight 30 or 40 weight with no problem? I have heard that a single weight is more stable and better for your engine than a multi weight given the mild to hot weather we have in these here parts. What do you guys think?
 
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2,635
Location
Chicago
The thiner the oil on start up the better. Good dino oils today are very shear resistant and do not generally cause any problems. [Big Grin]
 
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15,763
Location
NE,Ohio
I'd prefer a 15w40 or similar over the straight weight.30 years ago... your statement was undoubtable very true. Rand
 
Messages
453
Location
Galveston, TX
quote:
Originally posted by GreeCguy: Howdy fellow oilers. I live in Central Florida, so cold winter issues are not a problem with me. Therefore, should I still be running a multi-weight motor oil in "Big Red," or can I run a straight 30 or 40 weight with no problem? I have heard that a single weight is more stable and better for your engine than a multi weight given the mild to hot weather we have in these here parts. What do you guys think?
Straight weight dino is better. Use castrol HD-30. I always do, and it's never let me down.
 
Messages
1,904
Location
Bay Area, CA
The main problem of oil is how extremely thick they are at ambient temp. That is the whole purpose of multweight oils, they are thinner at a low temp than straight weight oils. There is very little downside to multi weight oils but thier is a big downside to straight weight oils.
 
Messages
700
Location
USA
Here is something i posted on a different thread. I did some quick numbers on startup viscosity of sae 30 Delo 400 vs delo 15w-40. Temp sae30 15w-40 59f 526cst 508cst 68f 367cst 364cst 77f 262cst 266cst 86f 192cst 199cst 95f 144cst 151cst 176f 21cst 25cst
 
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7,550
Location
North Alabama
I would have no problems running a straight 30 or 40 wt. oil if I lived in Florida. [Off Topic!] Does any oil company make a full-synthetic straight 30 or 40 wt. oil?
 
Messages
2,635
Location
Chicago
quote:
Originally posted by wavinwayne: [Off Topic!] Does any oil company make a full-synthetic straight 30 or 40 wt. oil?
Not real popular oil choice, I wonder why? [I dont know]
 
Messages
2,233
Location
Wisconsin
As WavinWayne indicated, running a straight weight during the summertime in the southern states is not a problem. Take a look at the viscosity numbers posted by JonS - the SAE 30 viscosity at 59F(15C) degrees is the roughly the 500 cSt of a 5W-30 at 32F. Many residents of northern states/countries have a daily cold start-up with an oil in the 400 to 600 cSt range for 4-5 months out of the year, so SAE 30 above 60F should generate no issues with cold start. [Smile]
 
Messages
40
Location
Connecticut
quote:
Originally posted by GreeCguy: Howdy fellow oilers. I live in Central Florida, so cold winter issues are not a problem with me. Therefore, should I still be running a multi-weight motor oil in "Big Red," or can I run a straight 30 or 40 weight with no problem? I have heard that a single weight is more stable and better for your engine than a multi weight given the mild to hot weather we have in these here parts. What do you guys think?
Isn't ANYONE going to explain that there is no "multi-weight" oil?
 
Messages
22,188
Location
Colorado Springs
quote:
Originally posted by Blue99: As WavinWayne indicated, running a straight weight during the summertime in the southern states is not a problem. Take a look at the viscosity numbers posted by JonS - the SAE 30 viscosity at 59F(15C) degrees is the roughly the 500 cSt of a 5W-30 at 32F. Many residents of northern states/countries have a daily cold start-up with an oil in the 400 to 600 cSt range for 4-5 months out of the year, so SAE 30 above 60F should generate no issues with cold start. [Smile]
See, now look at what you've done. You brought facts to the table that show a straight 30 weight would indeed be acceptable in a hot climate (and dare I say, preferred?). [Razz] Oh no, but what about the severe start-up wear. You'll starve the oil pump [Roll Eyes]
 
Messages
13,132
Location
By Detroit
quote:
Originally posted by wavinwayne: I would have no problems running a straight 30 or 40 wt. oil if I lived in Florida. [Off Topic!] Does any oil company make a full-synthetic straight 30 or 40 wt. oil?
All the Redline multigrades except 5w40 are essentially straight weight as they do not have viscosity index improvers added (so I have been told). Just happens the stuff is so excellent it meets the "w" ratings too.
 
Messages
2,233
Location
Wisconsin
quote:
See, now look at what you've done. You brought facts to the table that show a straight 30 weight would indeed be acceptable in a hot climate (and dare I say, preferred?). Oh no, but what about the severe start-up wear. You'll starve the oil pump
[Razz] ... Actually Gary Allen came up with a great line "your engine will grenade" as a satirical description of what the thin oil crowd envisions will happen, when running a 10W-30 in a 5W-20 spec'd engine. [Cheers!]
 
Messages
2,635
Location
Chicago
I find this whole thread strange but interesting. Here on BITOG synthetic oils are typically run 6,000 miles, oil filters are filled before install, 3 ounces of clean oil through the sump to clean it out, and the nth degree is not too far to go to get the most engine life and now it is go ahead and run 30W oil in the southern summers it is "good enough". Strange but interesting. [I dont know]
 
Messages
1,680
Location
CT
quote:
Originally posted by wavinwayne: Does any oil company make a full-synthetic straight 30 or 40 wt. oil?
if you look in the technical data posting top of Gas engine oil forum, Royal purple had a 30w, 40w, and 50w oil. But when I redid the numbers back in Jan. RP no longer had that info on their site so I don't know if they still carry it. And Amsoil has an SAE 30 diesel oil.
 
Messages
2,187
Location
Arizona
quote:
Originally posted by Ugly3: I find this whole thread strange but interesting. Here on BITOG synthetic oils are typically run 6,000 miles, oil filters are filled before install, 3 ounces of clean oil through the sump to clean it out, and the nth degree is not too far to go to get the most engine life and now it is go ahead and run 30W oil in the southern summers it is "good enough". Strange but interesting. [I dont know]
I agree. And even though "the nth degree is not too far," hardly anyone runs a pre-oiler and oil heater along with bypass filtration on their RedLine oil. It seems that it really IS all about cost even when we SAY cost is no object. The good Dr. Haas, for example, could save himself a lot of time and trouble with an oil heater and a pre-oiler instead of studying the dickens out of thin oils, plus it would be VASTLY more effective. [I dont know]
 
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