Tech Q&A: Should I use a heavier engine oil in the summer and a lighter oil in the winter?

We usually recommend to adhere to manufacturer’s recommendations on oil viscosity.  With that said, I personally prefer to go to the heavy side of the recommended oil viscosity for a given climate range.  At the shop here in Dayton, Ohio we use Motul 5W-40 for all late model German cars (except BMW M series) for all four seasons.  5W-40 easily covers the viscosity needs for these cars in nearly any conceivable temperature we are likely to see in our part of the world.  For BMW M Series we use Lubro Moly 10W-60 year round because that is what BMW recommends.  The only oil related issue that I disagree with the manufacturers on is the extended change interval now used by all the German makes.  Porsche recommends 20,000 miles or once annually between changes, BMW and Mercedes are both using condition based intervals that result in between 15 and 18 thousand mile changes.  We recommend changing the oil in half the time the manufacturer recommends or at about 7500 miles.

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Tech Q&A: What should I do to my car before storing it for winter?

What should I do to my car before I store it for the winter?

This is a pretty common question at our shop when the winter months are approaching or when someone is considering the first time purchase of a car they don’t anticipate driving in the winter.  Here in Ohio, where the roads get the salt, you want to park that baby until spring.

In my opinion, the question is addressing about 3 months out of the year.  We are basically answering “What should I do when I need to park my car for about 90 days?”

I know what you are thinking; do I need fuel stabilizer?, can I leave the oil in the car?, should I put the car on jack stands?, should I have the tires dismounted and hermetically sealed?.  I always flashback to that scene from Back to the Future III when I think of this.  You know, when Marty and 1955 Doc blast the DeLorean out of the cave where it has been stored since 1855.  Cobwebs and dust all over the thing and the tires have completely rotted away… one of the best movies of all time if you ask me.

Since three or four months is a really short period of time as it relates to the atomic half-life of molecules lets just be practical in answering this question.

The main things you’ll need to be concerned about when putting your baby away for hibernation are as follows:

You really should make sure your battery is in good shape and it is not too old (more than 5 years) when you put the car away for the winter.  Make sure the charging system has been charging the battery properly during the previous warm months.   If that’s all good then you’ll want to  disconnect the battery’s negative cable while it is to be stored.  This will minimize the “parasitic” drain while the car is not in regular use.  Parasitic drain is the result of the various loads placed  on the battery’s negative cable from consumers such as computer memory, clocks, security system and so forth that even older vehicles have.  Many newer vehicles have the ability to go to “sleep” when not in use but there will still be draw on the battery from “keep alive memory”.   The accepted normal value for parasitic draw is less than 25 milliamps.  This is not much but it could drain a battery over the course of a few months especially if conditions are not ideal.  It is even possible for a battery to become drained when it is disconnected, simply from electrons flowing through the dust particles laying on top of the battery!  All of this is of course just an effort to try to ensure that when you do dynamite the cave entrance, the DeLorean will start.

Air in the tires:
The other thing to be concerned with is tire pressure.  The air pressure in most tires will drop over time, therefore if you want to be able to drive the DeLorean out of the cave once you get it started, you will need to have air in the tires, assuming they didn’t rot off.    It would be a good idea to be well aware of your tires’ leaking habits, if they have any, and get those repaired before storage time.  Make sure the tires are properly inflated just before the car goes into storage.  Even a little higher than manufacturer’s specs would be fine here. When you go to retrieve your auto several months later, for that wonderful first drive of the year, it will almost certainly have lower air pressure in the tires than it did when you parked it.  10 psi lower than when you left it 4 months ago would not be any surprise at all.  In fact, the surprise would be if it didn’t lose pressure during storage.   Assuming you will observe lower air pressure after storage, one of your first priorities should be to get straight to a source where you can properly inflate the tires.

Aside from taking the above precautionary measures, there isn’t much you should bother with for storing the car for the winter and if these fail you when you go to retrieve the vehicle you will virtually guarantee the success of your effort if you bring with you some means for  checking/inflating the tires, and jump starting the battery.

There are a few other questions that I thought the normal reader would be wondering as I was writing these words, such as,  “what about condensation in the oil, what about flat spots on my tires, what about using battery maintainers/chargers, should I have the oil changed before or after I store the car, etc..”  but I really believe I answered the question rather completely above and that the other questions are topics all on their own.

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PS – I realize that many cars in my  area have already been stored for the winter months, which we are deep in the throes of.  I will be following up however with “What should I do to my car when I first get it out of storage?”  I know you all are anxious for that!