Viscosity Choice for Inactive Vehicle

[viscous]

My questions concern a vehicle that recommends 10W-30. 5W-30 generally functions well in applications calling for 10W-30, as both oils exhibit similar viscosities at operating temperature. 5W-30 thickens less as it cools, generally offering greater start-up protection, especially in cold temperatures. I would like to focus on protection offered BETWEEN starts, especially during long periods of inactivity.

1. Which viscosity, 5W-30 or 10W-30, would offer better protection from engine rust and corrosion during inactivity, and why?
2. Would you choose synthetic or conventional for long periods of inactivity?
3. For a vehicle specifying 10W-30, does anyone believe 5W-30 offers any possible DISADVANTAGES during the start and warm-up period?

 

[ABN_CBT_ENGR]

How long a period of inactivity are you talking about and (more importantly) what conditions of storage ( in a climate controlled room, barn, field, etc.?)

Never done a car like this in my life but I routinely prep machines for long term storage/seasonal shutdowns/ decommissioning and boneyard storage (LTS defined as >1 yr)

No oil is going to give and retain film strength, cling and barrier for corrosion for extended periods- this is why there are protective coatings for this.

Oil is not going to retard or arrest condensation or galvanic responses between touching metal parts ( fretting etc)

Sometimes you can fill them 100% full with a light oil ( displaces all air but has to be drained and properly filled before use and watch seals for leakage)

Sometimes you need to drain, dry ( with warm air) then fog them and use desiccants

Probably neither of those are applicable to a car but the problems described above are likely to be encountered universally and are basically the same in terms of mitigation.

 

[viscous]

How long a period of inactivity are you talking about and (more importantly) what conditions of storage ( in a climate controlled room, barn, field, etc.?)

My question was pertaining to LTS, or at least seasonal shutdown, stored inside but not climate controlled. Any thoughts on 5W-30/10W-30 and synthetic/conventional?

 

[ABN_CBT_ENGR]

My question was pertaining to LTS, or at least seasonal shutdown, stored inside but not climate controlled. Any thoughts on 5W-30/10W-30 and synthetic/conventional?

Been down this road ( not on multi grades but on ISO lubes)- for storage purposes ( not cranking and running), nothing matters but the additives ( the sticking additives) that control adhesion to the components and the corrosion/moisture ones.

The only storage protection any oil will give you is whatever barrier film coating it has on the parts and conversely the sitting oil will be constantly attacked by condensation and airborne debris ( all depending on storage conditions present wherever you store your car)

Those attacks will degrade whatever properties and whatever other reactions result ( domino effect)

There is also this unknown and indeterminate point where "all is good" ends and damage starts to begin (impossible for you to know or predict)

So the weight or dino/synthetic and most properties of motor oils wont even factor in protection requirements for LTS

 

[ChiTDI]

Can’t help you with question one, but #2 has a lot of support for conventional oil. Ask the farming community what they use when seasonally storing farm machinery and the answer is usually overwhelming for conventional. I don’t do this procedure, but had many customers who did. FWIW, they said protection was better when the “slippery oil” didn’t drain off the metal. Their words, (and money) not mine.

 

[aquariuscsm]

I never see a reason to go thinner than oem spec. Stay with 10W30.

 

[addyguy]

May not be right, but for really LTS, I’d want the most additives, ‘sticky-ness’ to coat the metal and prevent rust.
I’d use a 15w-40 HDEO with something like STP added.

 

[ripcord]

What kind of equipment and how long between starts are we talking about here?

Generally for long term storage, the advice engine manufacturers usually give is to change the oil before storage to remove acids and moisture from the oil. If you can remove the spark plugs and add a bit of oil to each cylinder and crank it without starting to coat the cylinders, that would be good, too.

If it's a vehicle that is just seldom driven, I think the best you can do is keep the oil change interval relatively short, store in a climate controlled environment to avoid temperature swings that cause condensation, and on that first cold start after storage, crank it over a bit with the ignition disabled to bring up oil pressure. 10w30 vs 5w30 is not going to make a big difference.

 

[NewtonPulsifer]

For a season or two just make sure it is clean moisture free oil before you store it (can’t go wrong with Mobil 1 extended for this IMO). Don’t overthink it with regards to weight.

Fuel stabilizer and remove the battery.

Maybe fogging oil for some types of motors if you think it will be stored for a year.

 

[viscous]

Ask the farming community what they use when seasonally storing farm machinery and the answer is usually overwhelming for conventional.

This may be true, and I've seen this argument before. However, there is also anecdotal evidence to the contrary here:

Quaker State GRoup III synthetic clings to the insides of my engine like there's no tommorrow. I popped open the oil filler cap and the stuff was everywhere (after 8 hours of sitting still). With Group II+ dinos, the oil would just drain down. With the GRoup III there was a nice layer of film all over everything.

 

[viscous]

May not be right, but for really LTS, I’d want the most additives, ‘sticky-ness’ to coat the metal and prevent rust.

Yes, I think this is the key, and MolaKule indicates that synthetics may "cling" naturally:

One is the "Macroscopic" view where we visibly see oil cling to engine parts. This clinging is done naturally by synthetics or by other oils using "clinging" additives (tackifiers such as polyisobutylenes, and by surfactants such as you see in Schaefer's #132).

I'm not sure what to believe, in terms of synthetic vs conventional "cling."

 

[demarpaint]

I'd look for a good synthetic high in esters, or use an additive like these which are highly regarded by some on this board. Both are claimed to help oil cling for long periods of time. Flame suit on for mentioning an additive.
Hy-Perlube ZDDP Replacement
Or:
Biotech EP
Another option is a pre-luber pump.

 

[ABN_CBT_ENGR]

Yes, I think this is the key, and MolaKule indicates that synthetics may "cling" naturally:

I'm not sure what to believe, in terms of synthetic vs conventional "cling."

Its a 2 part equation and essentially not different ( per se) but the next stage of the process.

Depending on the recipe, some oils "cling" by capillary action (more of a pore of metal thing) and the additives with different tackifiers cling by chemical (polar) attraction

That's great and all that to keep the oil there during operation.

For storage, you need a film strength on top of the cling for a barrier or whatever protection you think you have- you wont have long.

Try this experiment I have used- get a piece of steel and bead it down to white ( so it wont take long to react)

put a line of various oils on it ( and maybe one of grease too)- hang it up and let it all drain down and watch it.

It wont take long to see and visualize what I'm talking about

 

[Zaedock]

My questions concern a vehicle that recommends 10W-30. 5W-30 generally functions well in applications calling for 10W-30, as both oils exhibit similar viscosities at operating temperature. 5W-30 thickens less as it cools, generally offering greater start-up protection, especially in cold temperatures. I would like to focus on protection offered BETWEEN starts, especially during long periods of inactivity.

1. Which viscosity, 5W-30 or 10W-30, would offer better protection from engine rust and corrosion during inactivity, and why?
2. Would you choose synthetic or conventional for long periods of inactivity?
3. For a vehicle specifying 10W-30, does anyone believe 5W-30 offers any possible DISADVANTAGES during the start and warm-up period?

1. Neither will offer better protection from engine rust or corrosion during inactivity.
2. It doesn't matter. Someone mentioned Farm equipment - farms typically operate on a tight budget and conventional is typically cheaper and in their case of 15W40, more universal for vehicles and equipment. I would choose the cheaper and have. I haven't started my Willys in a couple years. It has Supertech 10W30 conv.
3. No, I don't believe there are any disadvantages. 5W30 (at least syn) has been spec'd for many OPE's for a while now. I bought a ton of PP 10W30 in Fall of '18 at $3.65/jug. IMO, 10W30 is becoming obsolete for most modern gas engines.

 

[viscous]

Zaedock, thanks for addressing each of my questions.

demarpaint, thanks for your suggestions.

For storage, you need a film strength on top of the cling for a barrier or whatever protection you think you have- you wont have long.

Seems logical... would you postulate that better film strength would be offered by 5W-30/10W-30; synthetic/conventional?

Try this experiment I have used- get a piece of steel and bead it down to white ( so it wont take long to react)
put a line of various oils on it ( and maybe one of grease too)- hang it up and let it all drain down and watch it.

Could you share your results?

 

[ABN_CBT_ENGR]

Seems logical... would you postulate that better film strength would be offered by 5W-30/10W-30; synthetic/conventional?

Could you share your results?

Let me combine them.

The test I described I have used for clients ( to prove why I needed to properly coat) with my finger of grease as the outlier showed that for the purposes of a defensive coating, all oils are equally worthless for the task. ( the grease represents fogging, cosmoline etc.)

All of them are subject to gravity and at best leave a sheen.

At that point, the quality of the sheen is subject to whatever forces act on it as to whether its good enough in the first place or how long it lasts, I usually put them outside where sun, rain and everything else gets it- no liquid prevents surface rusting very long.

Rough porous castings- forget it, sealed painted ones- somewhat better and so forth. The protected inside of a machine- coin flip but would be a degree more just because its protected.

Then comes a more subtle problem- these coatings (to varying degrees) catch and hold stuff like dirt, some chemicals, pollen, free moisture droplets and all kinds of stuff.

Depending on what's there and the protective coating- you may get tramp chemical reactions, biological and other stuff.

Then ( unless you do a proper flush before return to service) you literally do a "power dump" of all kinds of "stuff" as the thing runs and sloshes and cleans itself during normal operation.

This can ( depending on how much "stuff") shock the oil and render it unserviceable (or degrade it severely) and initiate damage.

The whole point is that what you store and how you store it and how you restore it to function is equally if not more important than what specific coating you store it with but those other factors need to guide the selection of the coating- not just the properties of a motor oil in terms of how well it does running.

 

[350Rocket]

Zaedock, thanks for addressing each of my questions.

demarpaint, thanks for your suggestions.


Seems logical... would you postulate that better film strength would be offered by 5W-30/10W-30; synthetic/conventional?


Could you share your results?

My girlfriend will want to kill me but I'm considering this experiment in our garage...I have m1 0w40 FS, Castrol edge 5w30, m1ep HM 5w30, conventional 10w30 motomaster oe plus and a mix of Castrol edge 10w30 and some straight 30 weight.

 

[350Rocket]

Let me combine them.

The test I described I have used for clients ( to prove why I needed to properly coat) with my finger of grease as the outlier showed that for the purposes of a defensive coating, all oils are equally worthless for the task. ( the grease represents fogging, cosmoline etc.)

All of them are subject to gravity and at best leave a sheen.

At that point, the quality of the sheen is subject to whatever forces act on it as to whether its good enough in the first place or how long it lasts, I usually put them outside where sun, rain and everything else gets it- no liquid prevents surface rusting very long.

Rough porous castings- forget it, sealed painted ones- somewhat better and so forth. The protected inside of a machine- coin flip but would be a degree more just because its protected.

Then comes a more subtle problem- these coatings (to varying degrees) catch and hold stuff like dirt, some chemicals, pollen, free moisture droplets and all kinds of stuff.

Depending on what's there and the protective coating- you may get tramp chemical reactions, biological and other stuff.

Then ( unless you do a proper flush before return to service) you literally do a "power dump" of all kinds of "stuff" as the thing runs and sloshes and cleans itself during normal operation.

This can ( depending on how much "stuff") shock the oil and render it unserviceable (or degrade it severely) and initiate damage.

The whole point is that what you store and how you store it and how you restore it to function is equally if not more important than what specific coating you store it with but those other factors need to guide the selection of the coating- not just the properties of a motor oil in terms of how well it does running.

What you're saying makes sense, but if we're talking about something that's only sitting for 6 months or less with fresh (Mobil 1 or something similar) in the sump, do I really need to change that oil that's had 3 minutes of run time while parking it in the barn, then sat unused for only 6 months with air filter etc intact and not open to the elements, as soon as I pull it out of storage?

That seems a bit extreme. When I first got the engine from the junkyard it had been sitting several years (possibly 10+), and the only damage done was rusted freeze plugs. I've put 13 years and 105k+ miles on since then without any issues.

Now I park it with fresh oil every winter and run that oil for a month or 2 in the spring (maybe 1k miles). I thought that was being extra cautious.

I know I should do a uoa but that costs more than the oil and filter for one extra change and I only have to do it 2 times a year now anyway.

 

[ABN_CBT_ENGR]

What you're saying makes sense, but if we're talking about something that's only sitting for 6 months or less with fresh (Mobil 1 or something similar) in the sump, do I really need to change that oil that's had 3 minutes of run time

I'm talking things in general and just adding things I have experienced ( with industrial stuff in extremely harsh environments at times)

In your specific case based on your description, I wouldn't call that LTS in the first place and just check level, crank and go (I would check the oil visually with maybe a blotter test after a day or so of running just to see if there was an "event" or free/emulsified water I might need to know about)

 

[OilUzer]

I've read that oils with ester cling betrer.

GTX Magnatec says it clings but with that price, I doubt if there is much ester in it. Maybe it's just intelligent. lol unless you pay the price and go with RedLine or Amsoil.

I've parked cars for 3-4 months with regular oil and nothing blew up.