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Site Donor 2024
Dec 13, 2002
Rochester Hills, MI
Is it OK to use synthetic oil for engines stored over the winter months ?

I recall reading that dino should be used for storage, but it was probably based more on folklore than fact. Seems that the last oil change before storage with synthetic would make more sense.
Stay with synthetic. I'll take this time to say one more thing. Don't change the oil again in spring. Why? It's still good that's why. Too many people are draining out perfectly good brand new oil each spring.

So if you go with a fresh crankcase full of whatever oil you normally run, when springtime comes keep that same batch in there and continue on to your normal interval (based on mileage)
I think most people change the oil in spring again (even after changing it in the fall) because it could have potentially degraded for 4-6 months of sitting open to the atmosphere. Thus costing a few more $$. Just a thought. I have heard that dino clings better, then i have also heard that synthetic clings better. I have not heard a clear answer to that one.

Edit: What happens the filter media sitting in oil for 4-6 months? I would think the paper would degrade.

[ December 30, 2002, 11:45 AM: Message edited by: JonS ]
"All oils can dissolve a certain amount of water into their chemistry and new, high-grade, high-purity, paraffinic base oil that has no additives or just an oxidation inhibitor will dissolve the least."

That's what my oil analysis book says. Now, whether dissolved water is bad for storage I can't say, and where you can buy such an oil I don't know. I've always thought that the advantage of using a mineral oil for storage is that it's cheap.
There are many facets to this question which prevent a simple answer. To begin with, synthetics as a class whether it would be PAOs or Polyesters tend to be more hydroscopic (i.e., water absorbing) than mineral oils. That is because their organic structure tends to make them be more polar which would create the ability for their absorbing greater levels of atmospheric moisture than petroleum oils. You now need to factor in the additive packages as some of these tend to enhance this absorption of water, and as we all know there are many different additive packages that are used. Tha absorption of moisture caused by the normal "breathing" of systems when place is a storage environment can do some considerable damage due to the generation of rust and system corrosion. Because of this, the Military that has lots of vehicles and equipment that are not always in active use requires an engine oil to be formulated with rust inhibitors to protect against potential corrosion problems that would occur if one were to use conventional oils that are formulated for SJ/SL/etc. service. There is also the problem that absorbed moisture can react with the individual additive ingredients and render them not as effective as they should. Again , we are talking about storage periods starting from 6 months and beyond. As a matter of record, many of the manufacturers of farm machinery (Deere, Massey Ferguson, etc.) have specifications for their engine oils that follow the exact same practice of the military.
"I have heard that dino clings better, then i have also heard that synthetic clings better. I have not heard a clear answer to that one."

The group V Esters have a polarity to metals so yes they stick to internal metals during storage but the Race dinos's like Valvoline and Kendall that have some tackifiers stick to metal like there is no tommorrow during storage. Group V's attach and the other types I spoke of clings.

There is a additive that Synergyn makes that clings or attaches,I cannot tell but it is sure good stuff
In a good motor with a good dino the miles can really be ran up with this additive and kills acids

[ December 30, 2002, 03:22 PM: Message edited by: dragboat ]
Once thing to consider if storing a car, is the use of dessicant and a car bag. If you are not familiar with the car bag, it is like a giant sleeping bag that you zip the car into with dessicant to absorb the moisture enclosed with the car when first stored. I have used this method for several years with great success, even the rotors do not rust.

This year, since I have work to do on the car, I plan to drive it once per month as the road conditions allow.
I asked a somewhat related question a few weeks back. My car is in storage until April. I had a supply of Synergyn 5w-30 sitting around just itching to be used, but I wasn't sure if it was better to install it now or in April when the car would be run daily ( I had some fresh Castrol GTX sitting in the crankcase which I installed before I put the car away in the fall). Terry Dyson convinced me to put the Synergyn in the car and get it working right away, indicating it had some good properties which would help. I don't know if that is just Synergyn or all synthetics, but I think you would be fine putting in the synthetic right away as well, and then run a full oil change interval upon daily use.

If a car (tractor, harvester, etc) is put away for the winter it should be with clean oil. Most engine or equipment manufacturers will not try to convince you to change again in the spring, as there has been little degradation of the oil just sitting there. Personally I doubt that it makes much difference whether it is synthetic or not, but I would use the same brand and type that will be used year around so as not to leave mixtures.
I like synthetics in engines that get a lot of miles, and dinos on engines that get changed on time intervals.
Yep, a lot of old wive's tales going around about certain oils being water absorbant.

I would use a blend or a synthetic oil and supplement the oil with 8 oz. of Schaeffer's #132 because of the added anti-oxidants and anti-corrosives contained therein.

[ January 01, 2003, 12:54 PM: Message edited by: MolaKule ]
Most of the "Rodder's" I know use Amsoil 15W-40 Heavy Duty Diesel and Marine Oil. They say this stuff is like glue on metal parts and has lots of anti-rust additives. On my boat motor (Volvo Penta 5.0 Gi), I can see a nice coating of oil on the valvetrain after a winter's layup using this stuff. No...I not a dealer. But, I always try to use what works! And, right now I'm trying the Schaeffers 10W-30 Series 7000 in my Volvo S70 T5.

[ January 02, 2003, 12:59 AM: Message edited by: darrenc ]
I store my Grand National every winter(in a unheated garage up north) with brand new Castrol GTX 10w-30 in the crankcase, and a full tank of fuel with some gas stabilizer. I've been doing this with the car since new some 15 years now and never had a problem starting, running, nothing. I also use three king-size cotton sheets to cover it for the dust, but that's it. I start it come spring, drive the tank low and refill before any hard driving and head to the next car show.

Originally posted by JonS:

Edit: What happens the filter media sitting in oil for 4-6 months? I would think the paper would degrade.

Well.. I am under the idea that the filter is not going under any hot-cold cycles.. so just sitting there cant be that hard on a filter..
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