Castrol SLX vs. Mobil 1 Extended Performance 5W-30

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Apples to oranges. The SLX is a considerably thicker oil designed for the German motors. M1 EP is thinner. I wouldn't run the SLX in the Honda.
 
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Originally Posted By: theaveng
???. They are both 5w-30. Why do you say the slx is thicker?
I will let the more technical members of this forum reply in detail, but one thing I have learned as a relative newbie here is that the xW-xx designations of any oils are very broad guidelines at best. There are other specs not displayed on the containers that tell the true story of the flowability of various oils at various temperatures.
 
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HT/HS is a better indication of how the oil behaves inside the motor. The Castrol has a HT/HS of > 3.5 cP; the M1 EP has a HT/HS of 3.0. Castrol SLX specs make it a competitor of Mobil 1 0w-40. It is a very bad choice for your Honda.
 
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Originally Posted By: theaveng
???. They are both 5w-30. Why do you say the slx is thicker?
Because 5w-30 is just a grade. Within that grade, there can be a number of actual viscosities.
 
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The SLX is an ACEA C3 rated low-saps oil which is mostly for modern diesel vehicles with DPF systems if I recall. Go with the M1 EP.
 
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Originally Posted By: theaveng
???. They are both 5w-30. Why do you say the slx is thicker?
Both oils are required to meet different requirements. German car manfacturers usually spec a higher HT/HS value for fluids meeting their approval specs. Now oil weights are just boundaries, below or above which an oil is classified. 5w30 weight has wide boundaries. Castrol SLX is designed with this in mind, hence a thicker 5w30 with a higher HT/HS value to meet the high speed driving specs of the European vehicles. M1 EP is an oil designed to meet ILSAC GF-5/ API SN certifications. These are usually applicable to Japanese/Korean/US manufacturers. The correct M1 oil you need to compare SLX to is the M1 5w30 ESP. The following are the specs for it : Viscosity, @ 40ºC : 72.8 @ 100ºC : 12.1 VI : 164 Sulphated Ash : 0.6 HTHS : 3.58 Pour Point, ºC : -45 Flash Point, ºC : 254 '
 
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Originally Posted By: dparm
Apples to oranges. The SLX is a considerably thicker oil designed for the German motors. M1 EP is thinner. I wouldn't run the SLX in the Honda.
+1. M1 5-30EP meets Honda HTO-06, and Dexos1 which are high temp low deposit oils, where your SLX doesn't as AFAIK.
 
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The M1 is noticeably thinner at both 40C and 100C. Why would you consider the SLX for your Honda? It has no need for a low SAPS high HTHS oil. If it did, Honda would have speced it. VW's "strict" standards apply only to VW. The Honda engine and emissions systems needs no such standards. It isn't that VW's standards are strict, rather it's that they're specific to the engine, emissions system and OCI the VW has. The gas Honda is unencumbered by the very specific requirements the VW has.
 

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Originally Posted By: Gabe
Castrol SLX specs make it a competitor of Mobil 1 0w-40.
Ahhhh now I understand why Volkswagen recommends this oil & labels it VW505 compliant even though it does not match the manual recommendation (5w-40). BTW the SLX wouldn't damage my honda engine would it?
 
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I doubt SLX would damage it. SLX is just thicker than what your Insight requires. You might (or might not) feel some drag when revving the engine hard, and you might (or might not) see some loss in fuel economy.
 

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Originally Posted By: fdcg27
You might (or might not) feel some drag when revving the engine hard
Interesting you bring that up. With the extra weight of the electric motor on the insight engine, if I redline it, it takes almost 2 seconds for the RPM to slowly drop from 6000 to 3000 for shifting to 2nd gear. Even longer if I want to skip from 1st to 3rd (6000 downto ~2000rpm). One time I took a coworker for a testdrive and he wanted to know why I waited so long between shifts.
 
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