Questions and Answers on Collector Car Storage

Should I start the engine every few weeks?

Some people think the engine should be run every few weeks to keep the oil coating on internal parts.  Others say it should be started and idled to keep the battery charged.  Neither of those notions is really valid, and both overlook the real harm multiple engine starts can cause.

When you start an engine in cold weather, you need a richer mixture. That’s why old cars have chokes.  Cold engines don’t run as well, which is why old cars have fast idle when they warm up.  When an engine runs rich during warm-up one of the things that happens is that unburned gasoline and combustion byproducts leak past the piston rings and into the oil sump.  I’ve seen oil levels rise on cars that sit in storage for this reason – they end up with a quart or more of polluted gas diluting the oil by winter’s end.

Clearly that is not desirable, and the best way to avoid it is by not starting the engine once the car is put away for winter.

OK, then what about the battery?

I suggest you install a battery tender to keep the electrics of your car alive.  If you have a pre-computer car there should not be many drains on the battery when it’s parked, and a slow charge every month or two should be fine.  Cars with computers – especially the ones from the 80s and 90s – tend to need a trickle charger connected all the time to stay healthy.

There’s always a risk the trickle charger will overcharge the battery over four or five months of storage.  To reduce the risk of that I suggest plugging the charger into a timer so it only runs a couple hours a day.  That’s enough to replenish any discharge but not enough to fry the battery.

Make sure your battery is fully charges before you put the car away for winter.

How about lubrication inside the engine?

Oil tends to flow downward.  If you leave an engine sitting for five years, most of the inside of the motor would be dry if you were able to look inside.  Does that matter?  Not really.  What matters is that the engine’s bearings and other moving parts be supplied with oil when the motor is first started.

Oil is trapped in the bearing journals, so there’s just as much oil in the bearings at the end of winter even if some oil has run off the crankcase walls.  But it’s not pressurized like when the engine is running.  It’s just there.  When you start an engine cold, it’s the film strength of the unpressurized oil that keeps metal from crashing into metal.  When that happens, you get wear.  Remember the ads where auto engineers say 90% of engine wear happening in the first ten seconds?  This is what they are talking about.

A modern high performance oil (like Mobil 1 5-30) has a film strength that’s over 100,000 pounds per square inch.  Cheap oil that’s been in a motor 7,000 miles may have a film strength that’s just 20,000 pounds per square inch.  There’s a big difference in protection between the two.

It takes anywhere from 5 to 30 seconds (depends on engine design, oil thickness, and temperature) for the oil pump to start delivering pressurized oil to the bearings so your engine is most vulnerable during that window.  Protect yourself with by filling your engine with fresh high quality oil before storage.

Protect yourself further by keeping your engine speed at idle, and don’t put it under load until it’s had time to warm up a bit.

What’s the talk about “putting a car up on blocks?”

One of the most annoying things that happens when a car sits for a year is called flat spotting.  That’s when the tires develop flat spots where there sat in contact with the floor.  Most times flat spots work themselves out in an hour’s driving next spring but sometimes they don’t. 

Putting the car on blocks – using blocks to lift the tires off the ground – prevents that and ensures your tires will be perfectly round when you start the car in the spring.  If you can't do that over inflating is the next best thing.

Should I store the car full of gas, or empty?

The answer depends on the length of storage.  Petroleum engineers say gas loses perhaps a point of octane rating every month it sits.  So the premium you put in your car this December will be sub-regular a year later.  It may not be good enough to even start the car in five years.

If your car is going to be stored a long time, or an open ended period of time, I suggest draining the fuel system.  Empty the tank and then run the car out of gas in the lines.  

If you are sure the car is only being stored for the season I suggest filling the tank because a full tank is less likely to get condensation inside.  Put Sta-Bil fuel stabilizer in the tank and be sure to fill with the best premium you can find.  If you are near an airport Avgas 100 is significantly better than pump gas for storage (running too) though it’s not legal for road use.  Also, Avgas 100 contains lead, so it's toxic for post-1975 cars with catalytic converters.  But it's great for vintage machines.

How do I keep mice out of my car?

There are a thousand suggestions for keeping mice out of stored cars.  I have yet to see one that works reliably.  

Gerald Acquiliano of the Rolls Royce Club swears by TANK odor eliminator - he says a container of this in the car, windows closed, will repel all pests.  I hope he's right!  He also suggests making sure windows are shut tight, stuffing a rag up the tail pipe (s) and putting a cover over the car.  All good suggestions.

There is one more plan I suggest:  Professional pest control backed up by insurance.

Many comprehensive coverages (comprehensive, collision, and liability are three parts of a typical policy) include damage from rodents.  Some collector policies exclude rodent damage – look at the fine print.

We fix quite a few cars every spring with holes in headliners, holes in seats, and eaten wiring.  Some of the claims run well into five figures, and many collectors are not aware that this kind of damage is often covered by insurance. 

I hope you find these suggestions useful, and I wish you luck and success, putting your cars back on the road for spring 2014!

Best wishes

John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, independent restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at www.robisonservice.com or in the real world at 413-785-1665