Prepping your Porsche 356 for Winter Storage
by Paul Masanek

[Webmaster's note:  On October 17, 2020, Paul Masanek and Pat Yanahan conducted our club's first virtual tech session over Zoom.  Over 20 club members participated.  For those who missed it or did not take notes, Paul has prepared this written summary of the material the session covered.]


So what’s the big deal? Just park the car and it will be fine.  Well as we have all experienced, cars love to be driven.  Park it for a while, and strange things seem to happen.  It’s even worse over the winter (especially in an unheated garage).  The major enemy is moisture.  When you drive your car, you have warmed up the engine, trans, brakes, interior.  When it sits, temperature goes low, then high, and your car is now wet.  This happens because the car has mass, and when it is cold it takes time to warm up.  This means the cold car is drawing the moisture out of the warmer moist air.  Today, we will review all aspects of your car that with some loving care, can survive the long storage unscathed.

We will cover the engine, gas, interior, paint, seals, chrome, tires, and car cover and battery.


When the engine runs, the heat drives the moisture out, but also blow by occurs.  This blow by (combustion gas that goes past the piston rings and contaminates the oil) will cause the engine oil to develop some degree of corrosivity.  Remember the moisture that occurs?  Couple that with corrosivity and you now accelerate aging of the engine internals.  Solution—change your oil and filter before putting the car in winter storage.  The oil will be perfectly fine for the next season.

As long as we are under the hood—I have seen many restorations with oxidation on the newly plated bolts and other parts.  Take a can of WD-40 and spray nuts, bolts, carburetor arms, anything that is plated and shiny.  WD-40 leaves a film that forms a barrier to (yes) MOISTURE.  Do not use WD-40 to lubricate locks.  The film will gunk up the lock internals!


We are fortunate that our cars have a shut off valve for the gas.  Firstly, I recommend filling the tank before winter storage.  Add Sea Foam or STA-BIL to the gas.  Follow the instructions on the can.   (BTW, I like using Sea Foam or Lucas top end lub during the driving season.)  The more gas in the tank, the less area exposed to Moisture in the tank.  However, those of us with T5 or earlier (suitcase gas tanks) have a situation where the gas level in the tank is higher than the carbs.  I have seen situations where the needle valve in the carb doesn’t seal closed.  Gas will then fill the carburetor and pass into the engine.  This will fill one of the cylinders and hydraulically lock the engine.  So turning the shut off valve to off (the rod under the dash set to ZU) will solve this problem.

Gasoline will also evaporate over time.  This will leave varnish and residue in the carburetor.  Ok, so how to fix this?  When you park your car for the winter, turn off the gas (see above) and run the engine until it dies.  This will use up the gas in the carburetor, leaving the float bowl empty.  If you want to get really fancy, have the engine cover open, and as the engine starts to sputter spray fogging oil (available at any parts store) into the air cleaner.  Be quick to get both sides and use the fogging oil to stall the engine.

Please note—it is advised to use your shut off valve during the driving season.  This will keep the seals in the valve operating properly.  Occasionally, put the valve in Reserve (RES opposite to ZU) and drive for 20 minutes.  This will use up the gas in the bottom of the tank which is where water will also collect.   That way if you do need Reserve, the gas will be fresh.


All of us know that “old car smell”.  That smell is usually caused by the interior deteriorating, mold, or maybe some greasy Cheese Burgers.  Think about what you do to prepare for a car show.  Cleaning and detailing the interior not only improves the appearance, but also protects the interior for the winter storage.  Apply the cleaner, then the Vinyl or Leather protectant.  Pat Yanahan recommends Lexol Vinylex Protectant and Lexol Leather Conditioner.  The Vinylex is good for dressing anything vinyl or rubber.  It is also great for tires and has a UV protectant feature as well.

A recent 1989 911 project was a car whose original owner had never treated the leather interior.  The leather was hard and stiff.  After 3 weeks of almost daily Conditioner treatment the leather came back to a soft flexible condition.  During summer driving months it is a good to treat the leather once a month to allow it to soak in and retain its flexibility.  The leather in your Porsche is first grade quality.  Leather that looks cracked and scuffed can be saved with the proper care.

Paint Conditioning

Tree sap and acid rain play a major part in attacking our paint.  The best system is to absolutely clean the paint surface before storage.  A good washing with Dawn liquid soap (from the kitchen) will remove everything including your wax job.  We are starting to see older cars with acid rain etching because they were not cleaned before storage—and that is not repairable.  During the winter storage or in the Spring you can clay the surface which will remove any microscopic residual dirt and also brighten the paint surface.  A 356 or 911 takes about 30 minutes.  Then polish and wax.  Hint: stay with the same brand of polish and wax.  Most formulators of the better products are matching the chemistry of the polish and wax to maximize results.  Don’t  buy the stuff shown on TV at 2 in the morning.  Another hint is if you drop your microfiber cloth on the ground, don’t use it again until proper laundering or you will scratch the painted surface.


This topic includes window and door seals.  These seals can (and will) dry out and crack.  You should use a good rubber product year-round (sunlight is a significant deteriorating factor).  Placing a ball of paper towel under the windshield wiper arms to take pressure off the wiper rubber is a good idea.  Some even leave the doors ajar and windows cracked open to keep pressure off the rubber seals.  If you are storing in a typical garage, I prefer to keep everything closed for fear of mice.  I also recommend putting dryer sheets (used when drying clothes) in the car.  Put these under the seats, in the trunk, and in the engine compartment.  Seems to keep vermin out.  If you ever find shells from nuts (I have), you have had a visitor!!


It is very (VERY) annoying to find your chrome is pitting.  It is also very expensive to have this corrected.   Remember our discussion about moisture?  We all use chrome cleaner, XXXX steel wool, glass cleaner, etc., to make our chrome shine.  These clean the chrome (and oxidation), but can leave the chrome unprotected from moisture.   If we can add a barrier between the chrome and moisture, we can prevent pitting.  I like to use a simple paste wax.  During the driving season, you can apply sparingly and still have that great chrome shine.  For winter storage, apply liberally.  That first shine up in the spring will leave you impressed.  Don’t forget the bezels around your gauges, and your door frames.


If your tires are over 6 years old, plan to replace them in the Spring.  It is also a good idea to look at wear and also check your tire valves.  Apply Lexol Vinylex Protectant (mentioned above), or another protectant.  I recommend filling the tires to ~40#.  This will prevent flat spotting and insure you have enough pressure so your tires will not be flat.  It is very bad to have a flat tire for an extended period of time.  In the Spring, adjust your tire pressures.  Front pressure should be 3# lower than rear pressure, 29 in the back, and 26 in the front is a good mid-range.  If you are more aggressive driver, you may want to go 1-2 # higher.

Car Cover

A car cover for indoor storage must be breathable.  Do not use a plastic tarp, as it will trap that dreaded moisture.


You will either have a “Maintenance Free”, or AGM (such as an Optima) battery.  Either way, batteries in storage survive best if they have a full charge.  If you leave a battery charger on your battery, make sure it is classified as a Battery Tender, or Maintainer.  This means the charger is smart enough to not overcharge the battery.  Make sure you connect the charger Red Lead to Battery Positive.  Some chargers do not check if the connections are reversed.  Charging with connections reversed can ruin your battery!!  If you do not have a maintainer type charger, you can remove the battery and put in your basmeent.  You will want a fully charged battery, as it will prolong the life of the battery and should have enough juice for that first (painfully a lot of cranking) start in the spring.