Ok to use M1 5W-30 HM as top off for Delo S 5W-40?

[Garak]

Thank you, fpracha. I think it's been well established over the long term here that Dave does not endorse specific brands. He's certainly not someone who's going to say that M1 is garbage and one should use PP, or the reverse.

 

[Hessam]

I would never question dave's outright knowledge about motor oils. He may very well save hundres of guys on this board money by recomending to them dino over sythetic, or PCMO over HDEO when and if their specific case calls for it.

And I completely understand that he does not endorse specific brands, but this discussion was more about HDEO oils rather than Brands. I don't consider HDEO a brand.

The point I was trying to make, was about his tone. Some of his posts are dripping with sarcasm, which isn't really called for.

He doesn't have to brag that he has thousands of UOA's in the database, more than everybody else on this board combined--everyone knows that. He knows that there's no way I'm going to 30 consecutive UOA's with the same oil to prove a point sceintifically (yet this is what he suggests I do????)


there are a lot of guys like me, who are not constant posters on this board. and we certainly don't know as much about motor oil as Dave does. I don't disagree with what you guys said about dave, but at leat to me, blatant sarcasm is uncalled for when you are trying to educate someone, or add your wisdom/knowledge to a topic.

I too, do learn from his posts, but could do without the dripping sarcasm...

""I've probably got more UOAs in my database than most of the other folks here put together. ..... At what exposure durations (mileage) do these supposed superior benefits manifest into tangible results? ""

 

[Garak]

Originally Posted By: Hessam
And I completely understand that he does not endorse specific brands, but this discussion was more about HDEO oils rather than Brands. I don't consider HDEO a brand.


I would agree that HDEO isn't a brand, but Delo is, and there was the mention of Delo in the same sentence as HDEO. In any case, the use of HDEO in a gasser, for instance, is a compromise, as is any choice. If one needs more ZDDP, great. If one is trying to consolidate oil choice in a fleet, great. If one gets an HDEO at a good price, fine.

However, there are times when it isn't optimal. HDEO's extra ZDDP is nice for my old F-150. 15w-40, however, isn't nice when it hits -40 in January. A 5w-40 or 0w-40 synthetic HDEO fixes that problem, but at a much higher cost. You get my point.

 

[fpracha]

Two questions arise in the context of using HDEO in a gasser:
- for a modern gasoline engine, is there any likelihood at all that an HDEO oil will cause higher wear and require more frequent oil changes ?
- for the relatively older gasoline engines, does an HDEO help to reduce the wear & tear and help to achieve longer OCIs (as compared to when using PCMO oils) ?

 

[Garak]

Those are two very, very good questions, but I suspect they're seriously application dependent. I don't think we'll find one pure answer for everything.

For the first one, I'd suggest higher wear is unlikely unless the HDEO chosen was an extremely inappropriate grade for the gasoline engine. If it were seriously too thick (or less likely, too thin), then we might see problems. I don't think running 15w-40 in a Prius in a Saskatchewan winter would be very prudent, and with plenty of cold starts, could, at least theoretically, lead to higher wear. How significant that would be is another matter. As for more frequent oil changes, again, that depends upon the application and to which PCMO it was compared. A 15w-40 conventional HDEO may not have the extended drain capabilities of GC or M1 0w-40 in a vehicle specified for those two PCMOs. However, if you find an application where OCIs are short and the xxW-40 grade of an HDEO isn't a problem, I don't think it will matter one bit. My G uses 5w-30 (and 40 grades in other countries). Its severe service OCI is only 3750 miles. If I were to use a 15w-40 HDEO, I doubt I would have any serious viscosity issues, and the OCI is ridiculously short anyhow. Heck, it might be better for extended OCIs than certain conventional PCMOs. But, PCMOs include everything from the cheapest SuperTech to the most expensive boutiques. I can spend under $2 a litre for the cheapest conventional or over ten times that on certain synthetics.

For the second question, it's certainly possible. Some vehicles do better with enhanced ZDDP, and that's more easily attainable with an HDEO. A lot of the older vehicles have no specification issues with HDEO, either. The G specifies SM/GF-4 or better in 5w-30. That's not going to happen in HDEO. The old F-150 specifies various grades in around SJ and older. Today's PCMOs are far better than the oils of the time, and today's HDEOs are better than what was available back then, too. For the old F-150, before the rebuild, I had to run something "stouter" to combat fuel dilution over even a short OCI. The "stouter" choices were Mobil Delvac 15w-40 in the summer and MaxLife 5w-30 in the winter. 5w-30 PCMOs would see the oil pressure life flicker at operating temperatures at idle near the end of the OCI.