Oil choice for larger Generac generator...

May we safely assume that this unit has an electric starter and is stored indoors when not needed? If that is the case, then I don't see the need for 0w-anything. Perhaps if it is stored in an unheated out building, but not if it lives in the garage. Personally I favor either 10w-30 M1 HM or 5w-40 Rotella T6 in my generators. They've been called upon to run from 32 to somewhere north of 90F without issues. Forget about the outdoor ambient temperature and think about where the oil temperature might be when you start it. You shouldn't need anything below a 10w-x if stored in an attached garage, even in New Hampshire.
 
So, interesting point you raise there. Yes, right now, it's stored in a attached, but unheated and not insulated single car garage connected to the house by a small mudroom. In the winter it gets cold enough out there for anything to freeze, and in the summer it gets pretty hot because there is no ventilation like a gable vent or anything. So, it's stored inside, but in generally outdoor temps. Also, I'm hoping to build some sort of permanent shed outside for it because when I do need it, it's a whole production to move out everything in front of it (it sits in the back corner of the garage and I park my car in there as well). It takes me a good half hour to get everything out of the way, roll it out back, connect the ground wire from the ground rod, and lug out the main power cable to connect to the house before I start it up and move down cellar to kill the main and switch over. It's also a pain when there is any sort of precipitation as all I have for shelter right now is a temporary little shed I made from three pallets and a few sheets of plastic roof material.

Eventually, it will be outdoors, but in a shed. Thankfully, it's not relied on for heat at all in winter outages as we use firewood for our primary heat source and I have a huge All Nighter stove in the basement that keeps the whole house warm by itself.
 
10w-x will work fine in the winter. 5w-x will start better well below freezing. Your T6 5w-40 should do just fine.

I have 10W-30 in my generators here in SE Michigan. No problems pull-starting in the winter. Temps are usually in the upper 20s when power goes out due to ice storms. Temps in the teens and below don't usually produce storms around here and therefore no power outages and no need for the generator.
 
Someone's suggestion of 20w-50 is absurd. After 17 years, I'm on my second Generac 16 kw standby generator. The first one had the frame rust out prematurely, being on the coast. Your manual and mine calls for 5w-30 synthetic which I use year round. Unlike yours, mine exercises for 10 minutes every week, so winter starts are important. Buy a name brand. No need to go crazy with a boutique brand. People who try to be smarter than the owners manual are not so smart.
 
Thanks for the input. I would run it more often if I didn't have to go through the whole process of getting out of the garage to do so. Once I have it in a more permanent location in a generator shed, I'll likely run it monthly to keep things fresh. I'm sure a normal 5W-30 would be fine, my only concern was the use of it in the warmer months when it's 90's out and the generator is running flat out for hours on end. I think going with something a little hardier like the Rotella 5W-40 can't hurt and will probably hold up a little better in that sort of environment. I realize I could probably throw in any old non synthetic in the right weight requirements and it would be fine.
 
I also suggest Shell Rotella T6 in either 5W-40 or the hard to find 0W-40...

Really tough oil, great for small engines...
 
The folks are looking at getting a 12-16kw.
I will plan a 1hr burn, loaded, kick the tires., run out five hours, dump and run same in as out.
I would love to find a hdeo syn 30, maybe a hd40 syn.

-harvey

p.s. first fill will be ST hdeo sae30/mmo/moly/rl zddp.
we have plans of a "heat" lamp, ever a start below "yatzee"
 
So far it has taken 2 years to accumulate 30 hours and it takes 1.5 qts with full pressure lubrication, a filter, and oil cooler? Put in literally anything marketed as motor oil with literally any API service grade from SH to SP and any multi-viscosity rating from 0w16 to 20w50 and change it every 50 hours or 2 years, whatever comes first. I guarantee it will last 50 years. If you want it to last 100+ years use a synthetic 5w30, 10w30, or 5w40 API SN or CK4 (or newer) and change it every 2 years or 50 hours for infrequent use but run the OCI out to 100 hours if you experience a really long power outage (i.e. if you let it run 24 hours a day for 4 days straight or 12 hours a day for 8 days straight).
 
Original poster was in NH. 0 bottom number is a must if you want to start it in winter. Unless it's stored in a heated area which is unlikely.
I pulled my 5500w unit off the ground with the recoil at 0f with 5-30w synth. in it. No issues pulling it over and starting after switching to a 0-40w full synth. oil. I use a 0-40w for year round protection.
 
Rotella T6 15W40
Motorcraft 15W40 (its high zinc)
M1 15W50
Vanguard 15W50

use any of these oils changed every 100 hours with the filter and sleep well at night. 40 or 50 in an air cooled, they get HOT, no 30 weight.
 
repairman54 said:
Original poster was in NH. 0 bottom number is a must if you want to start it in winter. Unless it's stored in a heated area which is unlikely.
I pulled my 5500w unit off the ground with the recoil at 0f with 5-30w synth. in it. No issues pulling it over and starting after switching to a 0-40w full synth. oil. I use a 0-40w for year round protection.
Click to expand...
Wow, must have been bonkers cold! I pull-started snowblowers with 5w30 in them in MN for over 20 years before 0w30 became commonly available and never pulled one off the ground.
 
Insane said:
Hey guys. It's oil change time on my generator and I'm trying to decide the best choice in oil for year round use from what I have to use here. I'm also interested in some suggestions on if there is something better to use in future changes. The generator is a large, portable 15Kw model and I've just crossed the 30 hour threshold to change out the break in oil that I put in new. The break in oil is Generac conventional SAE 30. Here is the model information:


It's a 30HP v-twin OHV engine with a spin on filter and oil cooler. It's taken me a few years to get to those first 30 hours of use, but it does power the whole house when we have an extended outage. I'm in NH, and it can get pretty cold here, but also hot in the summer. I don't use it enough to change the oil every season, so I'm trying to find the best all around weight for 100 hour change intervals.

The manufacturer suggests SAE 30 over 40 degrees, 10W-30 from 40 degrees down to 10 degrees, and synthetic 5W-30 below 10 degrees. I am planning on using synthetic year round, and I've got a few flavors of Penzoil Platinum here to use. I've got both normal and "high mileage" 5W-30, as well as "normal" 10W-30. I was leaning towards the 10W-30, but I've been reading some suggestions of using synthetic 5W-30 year round from Generac, as well as some posters in this forum suggesting the use of synthetic automotive oils are not the best choice on these air cooled engines. I've also seen mention of the "high mileage" variants of automotive synthetics have a more ideal additive package for these engines.

I do also have a jug of Rotella T1 SAE30...but it seems not ideal for year round use. So, what do you guys think? Also, what are some other suggestions for future changes if the PP is not ideal longer term?

Thanks!
Click to expand...
I have a 13 hp Generac and I only have had to run it a full week 15 years ago and I change out oil every 3 years as it get run 10 mins once a year and gets a outboard storage sprayed in the carb every time, and then the fuel system gets drained every fall. I pull the filter and drain it at the anti drain back flap with the back of a small drill bit. The filter is 9 years old.(90 minuts of run time) . I will switch it out this year. I only use it for loss of power that has not happen since the "big storm". I keep it going just in case I need it.
 
I have a 20k Generac permanently installed running on natural gas. It tests weekly and recently ran for 5 days straight with only an oil level check every 24 hours (eliminate the electrical load and stop the generator for about 20 minutes). It was installed in 2013. Used no oil!

I have been running Mobil 1 EP 5w-30 since replacing the original break in oil. Usually change it yearly, but did change it after that extended run. I live in Connecticut and do not have the additional battery and oil warmer. We had extremely cold weather one winter with -5 degree temperatures. I went outside during one of its weekly tests. The generator had cold soaked for a week. Started perfectly. No sluggishness or rough running.
 
As you are in central New Hampshire, you want to make sure it starts when an ice storm takes down your power grid.'

Here in Vermont, I use Pennzoil Ultra Platinum 5w-30 It always starts even in sub zero weather, and does not burn off very quickly.
 
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