Best 15w40 for very long term storage

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Jun 8, 2022
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I have a generator now, and I want to put a gallon or maybe two of 15w-40 in storage for it. If I am ever in a power outage a gallon will get me about 8 days of constant use run time - 16 oz per change / 24 hour intervals.

If I am lucky I may never need to use this - so I am looking for an oil that will keep best for years and years. I know technically most places rate 6 year storage, and likely they will last much longer than that. I will store this in a non temperature controlled windowless shed, and the most likely use case will be to run this thing while very hot and humid - south Carolina coast.

Some potential candidates I can get locally - although I could order about anything:

Shell T1 SAE 30 - cSt 100 @ 11.9 - I threw this one in as technically the spec is to use SAE30​
Shell T4 15w40 - cSt 100 @ 15​
Delvac Extreme 15w40 cSt 100 @ 14.3 -- full synthetic​
Delvac 1300 super 15w40 I think this one is cSt 100 @ 14.8, but the literature on this particular formulation confuses me. This one is cheapest - $13 bucks on walmart.com​

Or whatever else is out there. Leaning towards the Delvac Extreme because it full synthetic.

Anyone care to weigh in?
 
IMO, I don't think it will make a difference on what oil you use in a generator.
You are living in an area where there is no freeze or short time freeze.
 
When was the last time an event like that or similar has happened in SC. You're also going to need enough gas to run it that long non stop. Do you know how much fuel it uses per hour with your load on it.

A gallon would give you 8 intervals each under 200hrs. The cheaper delvac 1300 is still rated for up to 360 with the vds 4.5 spec but under 200 is what i'd do at most. Being me i think i'd change it at a hundred or so hours. I think regular hdeo will make it last just as long as delavac extreme. I doubt that gen will run for several thousands of hours in its life like construction ones do. The fact that you plan on changing it is already good. Most are abused and yet still last a few hundred hours on the factory fill.
 
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Either of the Shell Rotellas get my vote, either T1 or T4, I have used both for years in everything from OPE to the Kubota L2501 to our vehicles, it has never skipped a beat.
 
When was the last time an event like that or similar has happened in SC. You're also going to need enough gas to run it that long non stop. Do you know how much fuel it uses per hour with your load on it.

A gallon would give you 8 intervals each under 200hrs. The cheaper delvac 1300 is still rated for up to 360 with the vds 4.5 spec but under 200 is what i'd do at most. Being me i think i'd change it at a hundred or so hours. I think regular hdeo will make it last just as long as delavac extreme. I doubt that gen will run for several thousands of hours in its life like construction ones do. The fact that you plan on changing it is already good. Most are abused and yet still last a few hundred hours on the factory fill.
Good questions. How often - who knows, we have lost power for a few days at a time twice in the last decade. It depends on the hurricane gods. Hopefully never :)

Its a little 212cc generator and says change oil every 25 hours. It only holds 17 oz by spec, so 1 gallon will do almost 8 changes. I know many others don't but I would like to change it every 25 hours or so if I can - it takes about a minute.

I have never run this thing except to break it in and every once in a while as directed, but it claims to burn 1.9 gallons which is the tank size in 7 hours at half load, but I have no idea really. I usually store 15 gallons during hurricane season, and I know I can get into my two Nissan's if I am desperate and they hold 20+ gallons each. I think I would have 50-60 gallons of gas if I needed, assuming I couldn't resupply, which I imagine I could after a few days if I drove far enough inland. Even so, with a gallon of engine oil and 60 gallons of gas I could likely stretch it a couple weeks if I needed?
 
Run it out of gas (but warm) and weigh a quarter of a gallon of fuel on a postal scale. Pour that in, start it up, run a load on a kill-a-watt meter. Video it-- when the generator dies, the meter goes blank. Do some maths and you know your consumption.

As for oil, it won't matter. Better to protect the machine against rodents. If they hide acorns in all your cooling fins you'll have a bad time when it's needed.

If you don't have the meter your local library might.
 
Changing the oil every single day has me thinking. I think I’m going to make an external reservoir and use one of those submerged pond pumps to get the oil back to the crankcase. I may take one of those 60-gallon tubs and fill it with about 12 gallons of oil, put a 60lph pond pump in, and have a wide-open 1/2” line from the crankcase into the tub, and the pond pump to the dipstick hole. No way am I stopping even my Ryobi 4kW generator short of 3 days to do an oil change. I think I’ll even run LubeGard BioTech in the dump, and TW3 in the gas too while I’m at it.

OP, if you’re that concerned about it, buy a 5-gal bucket minimum, and maybe even a drum. Sorry for the sarcasm but some of our collective OCD seems, well, obsessive.
 
Delvac Extreme 15w40, or the 10w30 to share with cars as an emergency top off or fill!
Rotella T5 15w40 when considering budget.
Rotella T6 5w40 or 15w40 if ExtremedDelvac is hard to source locally!
Rotella T6 0w40 if you want to share with a bunch of 20 or 30 grade gasser cars too for emergency fill or top up!
And, another 15w40 available in some local stores https://www.walmart.com/ip/Chevron-Delo-XSP-Synthetic-Diesel-Motor-Oil-15W-40-1G/542461219

Don't need to store it for years and years. Just toss it into one of the vehicles and buy some new every 2-3 years.


My ol' generator is rated for 100hrs on pathetic conventional SAE30, 5w30 or 10w30... nothing special(as are most of my smaller engines). Could possibly double that interval with just the stout T4 15w40 before its stressed and maybe add another 100hrs for synthetic. I guess when possible, changing oil a little more often gives peace of mind. Similar, but smaller engines, in my lawnmowers have lifetime oil... just top off.

Amsoil 10w50 is another great choice:
Even Briggs knows about visc:

Not that I'd want to lug down my generator with the inefficiency of thicker oil, that previously mentioned Mobil1 15w50 can also be considered.

Your neighbor 4-cycle outboard might appreciate your 40 and 50 grade choices too when he sails into your driveway and 2nd floor window!
 
Changing the oil every single day has me thinking. I think I’m going to make an external reservoir and use one of those submerged pond pumps to get the oil back to the crankcase. I may take one of those 60-gallon tubs and fill it with about 12 gallons of oil, put a 60lph pond pump in, and have a wide-open 1/2” line from the crankcase into the tub, and the pond pump to the dipstick hole. No way am I stopping even my Ryobi 4kW generator short of 3 days to do an oil change. I think I’ll even run LubeGard BioTech in the dump, and TW3 in the gas too while I’m at it.

OP, if you’re that concerned about it, buy a 5-gal bucket minimum, and maybe even a drum. Sorry for the sarcasm but some of our collective OCD seems, well, obsessive.
I am a fan of sarcasm, but I don't think it really fits in this case. The manual says 25 hours OCI. A comparable Honda - after which this CCP unit was copied says 25 hours OCI as well. The case takes a pint of fluid. Its air cooled so the oil is going to get hot. There is no oil filter. They have an extended drain tube which means I can change it in literally 1 minute - not a made up number, that about what it takes.

I realize that you might find this OCD, but if this is the difference between having lights and cool drinks or not, then I'll spend the 1 minute and 2 bucks of oil. If that makes me OCD well so be it.

Probably would last years without changing the oil at all, but why chance it?
 
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I doubt brand will make any difference. I'm currently using a variety of 10w40 conventional in my cars that range in age from 15-probably slightly over 25 years old. These oils have been stored in a non climate controlled garage all these years and I see no problems with any of the oil. I'm also running 5-7.5K OCI's.
 
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So no one seems to have much issue on the storage part - ie syn is better than mineral oil storing long term or whatever? I am leaning towards mineral because I read it holds contaminants in suspension better then, but if syn stored better might go that route?
 
I have a generator now, and I want to put a gallon or maybe two of 15w-40 in storage for it. If I am ever in a power outage a gallon will get me about 8 days of constant use run time - 16 oz per change / 24 hour intervals.

If I am lucky I may never need to use this - so I am looking for an oil that will keep best for years and years. I know technically most places rate 6 year storage, and likely they will last much longer than that. I will store this in a non temperature controlled windowless shed, and the most likely use case will be to run this thing while very hot and humid - south Carolina coast.

Some potential candidates I can get locally - although I could order about anything:

Shell T1 SAE 30 - cSt 100 @ 11.9 - I threw this one in as technically the spec is to use SAE30​
Shell T4 15w40 - cSt 100 @ 15​
Delvac Extreme 15w40 cSt 100 @ 14.3 -- full synthetic​
Delvac 1300 super 15w40 I think this one is cSt 100 @ 14.8, but the literature on this particular formulation confuses me. This one is cheapest - $13 bucks on walmart.com​

Or whatever else is out there. Leaning towards the Delvac Extreme because it full synthetic.

Anyone care to weigh in?
You can't go wrong with any Shell Rotella T product . Amsoil also has a very good product , especially if you become a preferred customer , Mucho Grande $$ savings brother !
 
I personally wouldn’t store a generator long term. If you plan on relying on it, it should be excised regularly. Every 3-6 months under load perhaps.

I would be more worried about an E0 fuel. As far as oil, I’d run a 0w40 and be done with it. Depending on your climate, a 15w40 will work too.

I wouldn’t be too worried about having a “generator only” stash either. In a pinch, any xw30 will work assuming you already have some for a car, mower etc.
 
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