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Re: Oil Pressure Poll [message #366565 is a reply to message #366554] Tue, 07 September 2021 22:26 Go to previous messageGo to previous message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
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The one thing I have learned is that with today’s oils, thicker is not better. IMO, it is best to use as thin of an oil as possible, that gives you acceptable hot oil pressure. The thinner it is, the more oil you have going to bearings, reducing wear. The thinner it is the more oil is carrying heat away from moving parts. The thinner it is at cold temps, the quicker oil gets to the bearing surfaces reducing wear. The thinner it is at cold temps, the more oil you have actually going to those cold surfaces quicker, reducing wear. I use the 0W40 mainly because the “0” flows for my Wisconsin cold winter starts, (sometimes we leave for the south in -15*) while giving me the “40” for acceptable oil pressure on hot running. On cold starts, I have oil pressure immediately with the "0", and 45-48lbs hot running down the road, and 30lbs and a hot idle. I think it is Matt C. that once said, the only down side is the “0” also has a run-off factor when sitting for long periods, meaning because of the low viscosity, it runs off easier than the 5w to 15w weights when sitting for long periods. If my coach has been sitting for more than a couple of months, I get by that by pulling the ignition wire and turning the engine over until I see the needle move on the oil pressure gauge….then hook up the wire and start. A minor inconvenience but IMO worth the effort.

I think it was Matt that said that it is hard to find a "bad" oil out there, so to my way of thinking, if you have engineering and scientific testing that shows certain oils are better than others in reducing wear, why not go with it.

Oils have improved immensely over the years. Todays knowledge of chemistry and engineering have created oil blends that give us oils that far exceed the wear characteristics of yesterday’s blends. Todays blends have chemical replacement elements that duplicate the elements of ZDDP, so there may be only traces or no ZDDP in the oil, yet have extremely high wear characteristics. These oils have been formulated to assist todays engines in meeting EPA standards. Since most of us are not experts in the wear characteristics of oil, we act on what we know from our past knowledge and experiences. The past is behind us and while relevant, we need to look at present engineering going into the future. I’ve done as much as my pea brain will tolerate in researching the best oil for my Cad 500. So far the best I have found is a blog by a guy that calls himself 540Rat. He has taken the time using engineering techniques to test over 240 different oil blends, and ranked them by their ability to resist wear.

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

This is a tough read filled with testing, engineering data, a lot of self praise/bluster, and a lot of information that we don’t need, but is the best I have found to help me in my decisions relative to the oils that I am using in my vehicles. While it would be best to read most of the beginning info, for the meat of the blog, grab the scroll button and scroll about 1/10 of the way down to “WEAR PROTECTION RANKING LIST”. This lists oil in their ability to resist wear by measuring in psi their ability to keep metals from making contact. It should be noted that while he has tested an number of them ranked very high on this list that have an aftermarket oil additive, he does NOT endorse the use of oil additives claiming that you really don’t know what you are doing to the carefully engineered chemical blend when you pour in these additives. So he claims it is best to choose an oil that ranks high on the list straight out of the bottle.

The Wear Protection reference categories are:

* Over 150,000 psi = SPECTACULAR wear protection
* 135,000 psi to 150,000 psi = AMAZING wear protection
* 120,000 psi to 135,000 psi = FANTASTIC wear protection
* 105,000 to 120,000 psi = INCREDIBLE wear protection
* 90,000 to 105,000 psi = OUTSTANDING wear protection
* 75,000 to 90,000 psi = GOOD wear protection
* 60,000 to 75,000 psi = MODERATE wear protection
* 50,000 to 60,000 psi = UNDESIRABLE LOW wear protection
* Below 50,000 psi = CAUTION – EXTREMELY LOW wear protection
The HIGHER the psi value, the BETTER the Wear Protection.

I personally use # 1 5W30 Quaker State “Full Synthetic” = 152,674 psi. in my automobiles and #15. 0W40 Mobil 1 “FS” European Car Formula, synthetic = 127,221 psi, in my motorhome.

If you want to see where the oil you have been using ranks, do a command F or Control F, type in the brand of oil, and hit CR to advance through the article until you find it. Some of the oils that have been the staple of the GMC community for years are surprisingly low on the wear protection list.

Sooooo….judge for yourself. Choose wisely by making informed choices.
JMHO

Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.

[Updated on: Wed, 08 September 2021 06:34]

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