What do these numbers represent? I’ve always gone by cST at 100*C. 5w30 and 0w40 being close in that regard. (12-ish)
Air Cooled Standby Generac Generator oil questions
- Thread starter lgndryhr
- Start date
KV100 is cSt at 100C. HTHS is high temp high shear, measured at 150C in millipascal-seconds (pressure * time). It measures the oil's dynamic viscosity, not just the kinematic viscosity, so it's much more useful in terms of engine requirements.
I just a few days ago put Mobil 1 Extended Performance 5W-30 in my Generac air cooled engine and plan on leaving it in until about spring next year unless the hours pile up before then.
Stick with synthetic. Conventional oil breaks down way too fast when these air-cooled units are running 3600 rpm in mid-summer. It’s not worth the risk of seizing the engine just to save a few bucks.
I had similar questions about the setup, but the guys from Wolf River Electric handled the full maintenance run for me last season. They actually checked the gas pressure and valves too, which most people overlook. If you're doing it yourself, just keep a close eye on the dipstick every 24 hours during a long outage. These Generacs love to drink oil when they're working hard.
I had similar questions about the setup, but the guys from Wolf River Electric handled the full maintenance run for me last season. They actually checked the gas pressure and valves too, which most people overlook. If you're doing it yourself, just keep a close eye on the dipstick every 24 hours during a long outage. These Generacs love to drink oil when they're working hard.
He's saying that there is no way 40 grade oil (in this case Mobil 1 FS 0W-40) to be thinner than any 5W-30 just because there is a KV at 100°C and when the oils is tested the results define if the oil is 30 or 40 grade.
He's saying that some 5W-30 oils may have equal or higher HTHS than Mobil 1 FS 0W-40. HTHS measures the oil film at 150°C. However, there are not many 0/5W-30 oils that have higher HTHS than the Mobil 1 FS 0W-40. And yes, all of them are Euro ACEA C3 or A3/B4 oils.
Sort of, I'm saying that there's more than one way to measure "thickness" and one of them is more useful for the SAE grade that most consumers are familiar with, which is why it's still on virtually every product data sheet. Isn't necessarily as useful for measuring performance under load.
I'm curious about the actual question from OP here, I just purchased a house with a 15kW generac and the original owner is extremely meticulous about service and warranty, to the point where she's insisting she pays for a final service call during the final few weeks she lives there. I'm not going to argue about it, though in the future I'll likely switch to a low SAPS euro oil like @Tom NJ mentioned.
I used some google fu and according to the interwebs, many (most?) Generac generators in this size will come with an oil cooler.
So while yes I was in agreement, if the engine has a competent and excellent designed oil cooler, then a synthetic 5W20 will be fine. These are probably seeing 180-195 degree oil temps, rather than 240+.
What do we know about oil viscosity as temp rises? If the oil cooler can keep the temps down, then 20 weight oil at 185 degrees is thicker than a 30 or 40 weight oil at 240 degrees. Which is why, a 20 weight would be fine if it has a good oil cooler.
If it lacks an oil cooler, no way, no how, am I dumping a 20 weight oil into a generator in the south.
That being said... if its mine its getting at least a 30 weight in some flavor.
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