Originally Posted By: FZ1
Originally Posted By: CATERHAM
Originally Posted By: FZ1
So,then,you know better than the engineers that built,and the company that warrants,the car? I'm sure any synthetic,in the oem spec,is fine.
No, but I do know when a OEM spec's a 20wt oil, a HTHS vis of 2.6cP is what's expected; that's the viscosity of 95% of that grade. Consiquently M1 0W-20 (HTHS 2.6cP) is a better fit to M1 5W-20 (HTHS 2.77cP) regardless of the SAE grade on the bottle.
O. K. So,now you know more than the SAE?.......... Now you know more than all the users of M1 5-20 around the world??....... Not wise to take some general information and split hairs,Hoss. You don't have enough information to be so specific in this case. If this owner has a multi displacement Hemi,5-20 oil is REQUIRED for the MDS system to PROPERLY FUNCTION. Not 0-20......5-20. Did you inquire whether the Op's Hemi has MDS? No!
I have no idea what you're going on about, not sure you do either.
The SAE grading system is a range of viscosities.
The current M1 5W-20 formulation is now a "heavy" 20wt oil. The previous formulations were lighter (HTHS 2.63cP) but for whatever reason Mobil has chosen to thicken it up in it's current form.
They're not the only company to do this, Pennzoil Ultra 5W-20 is heavier (HTHS 2.7cP) vs PP 5W-20 (2.6cP).
This is not bad or good, it's simply what it is.
On the "good" side, since most 20wt's have a HTHS vis of 2.6cP having more 20wt oil's available that are heavier give the consumer more choice; i.e., selecting a heavier 20wt if needed instead of moving all the way up to a 30wt oil.