She’ll T6 15W-40 vs Amsoil 15W-40 SigSeries Max Duty

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Hello,
I have a 1988 Mercedes 420sel and it seems that I can use 10W-40, 15W-40, or 20W-50. Considering going with 15W-40 but only diesel options and the two I’m considering are in the title. I know little of oils compared to most on this site and am curious what the experts think. Could not find HTHS of t6 but amsoil’s seems to be around 4.5? Thanks in advance.
 

CleanSump

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So why are you considering a Diesel oil instead of a high HTHS Euro type oil? Just curious, not challenging your choices.
Mobil and Castrol have good Euro's or plain Jane American cheap, as do other brands and house brands.
 

88420SEL

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So why are you considering a Diesel oil instead of a high HTHS Euro type oil? Just curious, not challenging your choices.
Mobil and Castrol have good Euro's or plain Jane American cheap, as do other brands and house brands.
Because I was recommended 0w and 5W by others here but they had lower than 3.9HTHS. I assume higher is better? And I just refuse to put that oil in my car in my climate…. I would happily use it if I lived up north instead. Redline 15-40 is 4.7 which is Pretty much 50wt but my thing isn’t a race car. Also I have been told that the less viscosity spread means less VI and is better. Plus live in Florida and garage kept car never sees starts less than 45F (at the worst)in the winter
 
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Because I was recommended 0w and 5W by others here but they had lower than 3.9HTHS. I assume higher is better? And I just refuse to put that oil in my car in my climate…. I would happily use it if I lived up north instead. Redline 15-40 is 4.7 which is Pretty much 50wt but my thing isn’t a race car. Also I have been told that the less viscosity spread means less VI and is better. Plus live in Florida and garage kept car never sees starts less than 45F (at the worst)in the winter
What are you putting this car through something that requires an HSTS over 3.9?
 

88420SEL

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What are you putting this car through something that requires an HSTS over 3.9?
Nothing. I baby it lol. Just want maximum wear protection. Probably wasting money with amsoil? Car rated up to 7500mi OCI in 1988 prob with conventional.
 
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Nothing. I baby it lol. Just want maximum wear protection. Probably wasting money with amsoil? Car rated up to 7500mi OCI in 1988 prob with conventional.
Obviously its your money and vehicle but you could save some no differentiable performance difference with a normal euro oil. Especially since you baby it
 
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T6 is 24 I think but I need zinc and it has 1050ppm of it. If Castrol had zinc I would go for it
This is from 2013 so it may not be valid still but its showing 1212ppm if that's what you're looking for
 

88420SEL

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Obviously its your money and vehicle but you could save some no differentiable performance difference with a normal euro oil. Especially since you baby i
This is from 2013 so it may not be valid still but its showing 1212ppm if that's what you're looking for
I think it was reduced or I may be wrong. I know m1 fs has enough zinc though, jut not cold enough to use it.
Btw one oil change without filter for my car with t6 is $50. Amsoil will be 80+…..
 
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HTHS is mostly irrelevant to you if you're babying the car...

Edge 0w40 is phenomenal oil for the price @ walmart right now. Zddp is around 950 to 1050 ppm per UOA data. I think it would be an excellent candidate for that engine.
 

88420SEL

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M1 15w-50. Not a super thick 50, 4.7 HTHS, 1300 PPM zinc. You want ultimate wear protection in a climate that never see below freezing temps? This is probably the best option. It's also A3/B3 rated.
Thanks. Yeah 4.7 is a deadline 40wt pretty much lol.
 
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Thanks. Yeah 4.7 is a deadline 40wt pretty much lol.
It's within the range of HTHS expected for a 50. Most 15w40s and some of the better 10w40s (Valvoline Maxlife/Durablend, M1HM, and Quaker State) will be in the 4.0 range. Outside of monstrosities such as Redline or Amsoil it's highly unlikely to find a 15w40 with greater than 4.2 HTHS. 4 is very solid for a 40wt and is on par with a straight 40 with no VII. I doubt you will see much difference in fuel economy between 15w40 and 15w50, in fact you'd probably get better economy from M1 because it has a nice dose of friction modifiers compared to an HDEO 15w40.
 
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I think it was reduced or I may be wrong. I know m1 fs has enough zinc though, jut not cold enough to use it.
Btw one oil change without filter for my car with t6 is $50. Amsoil will be 80+…..
The temperature is irrelevant, "not cold enough" has no meaning. You can use an oil with a 0W winter rating in any climate.
 
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T6 is 24 I think but I need zinc and it has 1050ppm of it. If Castrol had zinc I would go for it
It has more than enough for your application or for most any application for that matter. If you don't think it has enough what are you basing that upon? How much do you think you need? Why do you think that an oil with MB 229.5 approval isn't sufficient for your vehicle and engine?
 

88420SEL

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It has more than enough for your application or for most any application for that matter. If you don't think it has enough what are you basing that upon? How much do you think you need? Why do you think that an oil with MB 229.5 approval isn't sufficient for your vehicle and engine?
I’m not saying you are wrong but I asked two specialist mechanic and they said not to go different from the Manual. Zinc content based on flat tappets.
 
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I’m not saying you are wrong but I asked two specialist mechanic and they said not to go different from the Manual. Zinc content based on flat tappets.
1000ppm zinc should be sufficient for your engine.

With that said, I do like the M1 15w50 recommendation above. A stout oil that will do great in Florida.
 
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I’m not saying you are wrong but I asked two specialist mechanic and they said not to go different from the Manual. Zinc content based on flat tappets.
Flat tappet engines only require high ZDDP levels during break-in or if you have very high spring pressures.

What does the manual say is a required ZDDP level?
 
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