Castrol 20w50?

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9
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I have used Castrol 20w50 in all my vehicles, with the exception of my 97 Vette which called for Mobil 1 5w30. Now I have an 04 Silverado with the 6.0 HO motor, and it dosen't specify synthetic, just 5w30. Any thoughts on if I should go with Mobil 1 or Castrol? I live in a hot climate and have never used anything other than the 20w50 or Mobil 1.
 
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666
Location
Triad, NC
I don't know ..... I would not put that heavy of an oil into the vehicles you mention. Not even in FL. Actually the manual explicitly states not to put 20W-50 oils and the like into those vehicles. If you want a thicker oil, go with some of the synthetics from Amsoil, Castrol GC, Redline or, if you want to stay the dino route, any "high mileage oil" in the 5W-30 or 10W-30 viscosity. High mileage oils are formulated at the very "thick end" of the viscosity scale for each of these oils.
 

bobbyinfl

Thread starter
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I just wonder why the 20w50 stuff sells so well- it's always available in all the auto stores and I've used it for the past 20 yrs or so because I was under the impression (misconception) that heavy was good in hot weather. Maybe in the older vehicles with loose tolerances, but not in the newer ones?
 
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509
Location
Las Vegas, NV
bobbyinfl, you summed it up perfectly. Many people just buy the 20W-50 oil because it is what they have been using forever or they have an old clunker that burns oil like crazy. Some people just don't read their owners manual and will put something like 20W-50 in a new Ford or Honda that is required to use 5W-20. [I dont know] [Welcome!] to the bobistheoilguy message board. [ December 02, 2003, 11:36 AM: Message edited by: Sin City ]
 

bobbyinfl

Thread starter
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9
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So, would it be appropriate to go with 10w30 in the new Silverado? The owners manual says both are OK unless it gets below 0. I just think 5w is too low for FL but maybe it doesn't matter.
 
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666
Location
Triad, NC
Using 5W-30 or 10W-30 is not really a matter of thin or not because 5W-30 and 10W-30 on differ in cold viscosity (40F). Viscosity at operating temperature (200F) is identical for both. This is achieved by adding more VIs to the 5W-30 formulation. In general, 5W-30 is better since it lubricates faster on start up, which is where most wear in an internal combustion engine occurs anyway. The reason 10W-30 can be preferred is the fact that is uses less VIs and is therefore more shearstable over longer drain intervals. On a 3K miles drain interval I would always use a 5W-30, even in FL. Use a good synthetic like Amsoil, Castrol GC, Redline (and others) in the 5W-30 viscosity and you'll never look back.
quote:
Originally posted by bobbyinfl: So, would it be appropriate to go with 10w30 in the new Silverado? The owners manual says both are OK unless it gets below 0. I just think 5w is too low for FL but maybe it doesn't matter.
 
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453
Location
Galveston, TX
quote:
Originally posted by bobbyinfl: I have used Castrol 20w50 in all my vehicles, with the exception of my 97 Vette which called for Mobil 1 5w30. Now I have an 04 Silverado with the 6.0 HO motor, and it dosen't specify synthetic, just 5w30. Any thoughts on if I should go with Mobil 1 or Castrol? I live in a hot climate and have never used anything other than the 20w50 or Mobil 1.
Castrol GTX 20w50 is great stuff, don't let anybody tell you different. Just because Xw-30, Xw-20 are "Flavor of the Month," the "In Thing," does not mean that all the tried-and-true "Old Favorites" are No Good. Most of my life, I used Castrol GTX 20w50. Only in later years, after I talked to Old Timer mechanics, did I use Castrol HD-30 in place of GTX. It seems, the monograde dino is just as thick, but without the viscosity index improver polymers. In your climate, you can use 20w50 without any ill effects. Apparently, you have already been doing so for many years. So, what are people telling you now? Suddenly, because 20w50 is no longer "Flavor of the Month," you must stop using it? And convert to water-thin newfangled snake oils? [No no]
 

bobbyinfl

Thread starter
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9
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Wow, now I'm more confused. I thought deciding between dino vs synthetic was my major problem, now I don't even know which visc to go with. I have had great results with Castrol 20w50 in the past, but nothing over 50K miles to base a decision on. Iplan to keep the Rado for a long time and won't put more than 7-8K a year on it. Maybe an annual OC with synthetic is right for me.
 
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666
Location
Triad, NC
That's just plain flim-flam [Big Grin]
quote:
Originally posted by Flimflam:
quote:
Originally posted by bobbyinfl: I have used Castrol 20w50 in all my vehicles, with the exception of my 97 Vette which called for Mobil 1 5w30. Now I have an 04 Silverado with the 6.0 HO motor, and it dosen't specify synthetic, just 5w30. Any thoughts on if I should go with Mobil 1 or Castrol? I live in a hot climate and have never used anything other than the 20w50 or Mobil 1.
Castrol GTX 20w50 is great stuff, don't let anybody tell you different. Just because Xw-30, Xw-20 are "Flavor of the Month," the "In Thing," does not mean that all the tried-and-true "Old Favorites" are No Good. Most of my life, I used Castrol GTX 20w50. Only in later years, after I talked to Old Timer mechanics, did I use Castrol HD-30 in place of GTX. It seems, the monograde dino is just as thick, but without the viscosity index improver polymers. In your climate, you can use 20w50 without any ill effects. Apparently, you have already been doing so for many years. So, what are people telling you now? Suddenly, because 20w50 is no longer "Flavor of the Month," you must stop using it? And convert to water-thin newfangled snake oils? [No no]

 
Messages
666
Location
Triad, NC
Why don't you go with what is recommended in your manual and choose a good synthetic or dino? I am sure the OEM manufacturer had a reason to warn about 20W-50 oil in the manual and did not just do it 'cause there was space left on a manual page for more words to be printed.
quote:
Originally posted by bobbyinfl: Wow, now I'm more confused. I thought deciding between dino vs synthetic was my major problem, now I don't even know which visc to go with. I have had great results with Castrol 20w50 in the past, but nothing over 50K miles to base a decision on. Iplan to keep the Rado for a long time and won't put more than 7-8K a year on it. Maybe an annual OC with synthetic is right for me.
 
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3,593
Location
Outside smalltown, IL
Couldn't have said it better myself... [Wink]
quote:
Originally posted by Alex D: That's just plain flim-flam [Big Grin]
quote:
Originally posted by Flimflam:
quote:
Originally posted by bobbyinfl: I have used Castrol 20w50 in all my vehicles, with the exception of my 97 Vette which called for Mobil 1 5w30. Now I have an 04 Silverado with the 6.0 HO motor, and it dosen't specify synthetic, just 5w30. Any thoughts on if I should go with Mobil 1 or Castrol? I live in a hot climate and have never used anything other than the 20w50 or Mobil 1.
Castrol GTX 20w50 is great stuff, don't let anybody tell you different. Just because Xw-30, Xw-20 are "Flavor of the Month," the "In Thing," does not mean that all the tried-and-true "Old Favorites" are No Good. Most of my life, I used Castrol GTX 20w50. Only in later years, after I talked to Old Timer mechanics, did I use Castrol HD-30 in place of GTX. It seems, the monograde dino is just as thick, but without the viscosity index improver polymers. In your climate, you can use 20w50 without any ill effects. Apparently, you have already been doing so for many years. So, what are people telling you now? Suddenly, because 20w50 is no longer "Flavor of the Month," you must stop using it? And convert to water-thin newfangled snake oils? [No no]


 
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1,759
Location
Elizabeth City NC
I have used this oil for many years also. I use it in the TR3 because this is what the owners manual recommends and it has done fairly well. I have used it in my toyota cressida because it has many miles and uses oil. I am finding a couple of things out doing an auto-rx treatment. One is I don't have to use this thick an oil to slow consumption. Two is it really reduces the miles per gallon your car gives you. I am now burning much less 10w-30 than 20w-50 by using auto-rx and I am getting a 10% milage improvement with the 10w-30. I don't know yet what my final consumption figure will be as I have one more treatment to do on the engine. However my thinking now is 10w-40 or 15w-40 maybe even 10w-30 is the way to go once I finish my treatment. GTX is an excellent oil and has slightly better spec than delo 400 which is also an excellent oil, however they both are expensive in my area and chevron supreme is only 1.08 and starting to be my choice now.
 
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82
Location
Rhode Island
One of the guys at work has a 2002 Avalanche with the 8.1 v-8, wich I understand is a very similar design to the 6.0. He started off using 5w30 but the piston slap and consumption were so bad that he eventually started using 15w40, and even with that it has noticeable piston slap and consumption, but not as bad as with the 5w30. Keep in mind that I am not at all against thin oils, I run penzoil 5w20 in my truck with no consumption and it is as quiet as a mouse. I just don't know if 5w30 is the best viscosity for this particular application. [I dont know]
 
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666
Location
Triad, NC
Nope, the 8.1 is an entirely different engine design from the 6.0. The 6.0 is an LS style engine like the 4.8, 5.3, 5.7 and 6.0. Difference here is only stroke and bore to create the displacements. The 8.1 is much closer to the old Chevy big block and has no commonality with the LS style engines.
quote:
Originally posted by BlackF250: One of the guys at work has a 2002 Avalanche with the 8.1 v-8, wich I understand is a very similar design to the 6.0. He started off using 5w30 but the piston slap and consumption were so bad that he eventually started using 15w40, and even with that it has noticeable piston slap and consumption, but not as bad as with the 5w30. Keep in mind that I am not at all against thin oils, I run penzoil 5w20 in my truck with no consumption and it is as quiet as a mouse. I just don't know if 5w30 is the best viscosity for this particular application. [I dont know]
 
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451
Location
Bribie Island, Oz
I agree with FlimFlam [Big Grin] There is no way I would use a 5Wxx or 10Wxx in any vehicle with a climate similar to Florida. I have cold sweats (or is that hot flushes), just thinking about it. Dave [ December 02, 2003, 04:13 PM: Message edited by: DavoNF ]
 
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82
Location
Rhode Island
Thanks Alexd, I was under the impression that the 8.1 was from the same family of engines. I am glad to hear that the 6.0 is different, because I am not at all impressed with the 8.1. it sounds like an old, tired engine, and drinks oil like a runner drinks water after a marathon! [Duh!] [crushedcar]
 
Messages
252
Location
AB, Canada
Sin City...you said:
quote:
Some people just don't read their owners manual and will put something like 20W-50 in a new Ford or Honda that is required to use 5W-20.
Some people in Europe and Asia DO! read their manuals...and find out that 15-40 and 20-50 ARE! ok to use in their cars, provided ambient temp. is appropriate...ie HOT! It seems funny that identical engines outside of N.A. specify very different (thicker...) oils for hot climates... [Eek!] [Confused]
 
Messages
666
Location
Triad, NC
Yeah blackF250 ... unfortunately they all have their problems ... pistom slap and oil consumption is also rampant in the ranks of the LS style engines. Form looking at the truck boards, it even seems that the 6.0 is the worst slapper .....
quote:
Originally posted by BlackF250: Thanks Alexd, I was under the impression that the 8.1 was from the same family of engines. I am glad to hear that the 6.0 is different, because I am not at all impressed with the 8.1. it sounds like an old, tired engine, and drinks oil like a runner drinks water after a marathon! [Duh!] [crushedcar]
 
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3,216
Location
BC, Canada
I wonder if highly FMd engine oils are keeping the engines from breaking in properly. Many of the HDMOs advertise "protects against cylinder liner polishing". Perhaps a single grade HDMO would allow the rings to seat or wear-in better than energy conserving GF-3 PCMOs. [I dont know]
 
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