5W30 Synthetic

[Best F100]

First post for me:

I have an air cooled, Guardian Model # 04760 (13kw NG) which I have owned since 2004. Since that time, we have several power outages. The worst have been for 36 concecutive hours in both 10F and 90F degrees.

After break in, I had been using Mobil 1 5W30 per the manual. I decided to use Castrol Syntec 0W30 synthetic, yes 0. I noticed right away that the generator was noticeably, quieter during the exercise cycle and during the outage. (Maybe a decible or two - I have no sound instrumentation). Not as much valvetrain and mechanical noise, and a bit smoother running. Many think it is too thin an oil, but actually, it flows like a 0 during start up and is a 30 wt at operating temperatures (almost a 40 wt oil). It stood up well to our 90F heat. Make sure it says "Made in Germany" on the back. I bought mine at Autozone.

I have run this Syntec year round, and I am sold. Since the big BMW's and Mercedes run this oil on Autobahn, it must be good stuff. I know everyone's choice of oil brand is personal, but I figured I'd just share my experience with everyone. Maybe my neighbors won't complain about generator noise next time, as they wait for their power to come back on and see my lights on!

[Kelly Myers]

Very odd that it would be running quieter. 0w/5w/10w-30 are all 30 sharing just about the same kinematic viscosities. All that oil has the same viscocity at 200 degrees.

[Bill Liedtke]

But it is slightly "thinner" at start-up temps and that is when you first hear the unit. If the sound level rises as the temperature increases you likely would not even notice it.

I guess as long as there is no DOWNSIDE and he believes it is quieter, then it might as well be fact! Perception is reality in some cases.

[Best F100]

No one may believe me when I say that running Castrol 0W30 (made in Germany on the back) is noticeably quieter than Mobil 1 5W30 in an air cooled generator, but my ears know the difference, listening to the exercise cycle every week. The engine roar is the same for both, but the valvetrain clatter noise is more muffled with the Castrol.

I do know that Mobil 1 5W30 is "thinner," and closer to a 5W20 than a 40 wt oil in viscosity at operating temperature. Maybe for fuel economy purposes in an automobile. (Even pours like ice tea, or paint thinner at room temperature).
Castrol OW30 is a bit "thicker" at operating temperature (almost a 40 wt oil) but according to the quart in front of me "will pump in cold weather and allow for unaided engine starts down to -40F". It pours out of the quart in a bit thicker consistency.

I know, some folks with GM V8 engines (Corvettes, Chevy Pickups etc.) have noticed the same differences (valvetrain noise, "piston slap") between the two oils at start up. I have just changed my oil for the winter today. Unless it is going to get colder than -40F here in Michigan, I think I am OK for power outages this winter. With either oil, I am sure these standby generators will outlive both you and I with good maintenance. I find it interesting that, I know of a couple of folks in Florida who have been though more than I hurricanes using Mobil 1 15W50 with their air cooled generators (power out for weeks at a time) and you could not make them use anything else.

Great forum Kelly. Kelly, what engine parts are most likely to be the first to "wear out" after many years of long term usage? Pistons? Exhaust valves? Something else?

[Kelly Myers]

I'm pretty sure on the air cooled line, we will see rings wear out before anything else. Just speculation.

Just for the heck of it, I'm going to DB test a generator, and try your oil and see if there is a difference.

[Bill Liedtke]

Best F100,

I did not mean to imply that your perception is not truly a reality. It's just that both oils *should* act the same at run temperature. I have a ZR-1 and a C5 highly modded vette and I switch back and forth between Mobil 1 and Castrol full synthetic and I have never noticed a difference whatsoever. 3 db is like twice as loud isn't it? I can't remember, but I should being a Ham. I just know 3 Db is a LOT louder so if you feel it is even a couple db quieter, that is significant!

[Jason]

Indeed, every increase in 3db is a doubling of power:

http://www.pmel.org/handbook/HBpage22.htm

[cosmicvoid]

Yeah, but 3db doesn't sound twice as loud. I'd guess that 10 db sounds twice as loud, but loudness is very subjective.

I think I read long ago that 1 db was regarded as the "just noticable difference" in sound level.

[Jason]

Yeah, according to this link, it takes about 10db to be roughly twice as loud:

http://www.rcaanews.org/noiselev.htm

[Bill Liedtke]

yes, you are all correct! 3db is double the power, not double the loudness. When I switch from 100 watts out of my ham transmitter to 1500 watts output, the gain on the other end is about 12 db. And yes, a lone decibel is the smallest increase in sound MOST people can detect. I like Castrol products and will make sure I use it next go around. I finally put an hour meter on my generator after replacing the stator. I wonder what the number of hours between changes should be? I change mine every spring regardless.

You can buy the tiny Briggs & Stratton hour meters for 19 bucks on Ebay.