During winter storage, is it bad to start your 911 and let it idle for about 15 mins?

[sugarwood]

A) Run for 5 mins.
B) Run for 15-20 mins.
C) Not starting it for 4 months.

Can we rank them?
Let's assume actually driving the car is not an option.

Everyone agrees it's bad to just start it for 5 mins since it's not warmed up, and condensation is not burned off.
Well, what if you start it and let it idle for 15-20 mins so it does get warmed up?
What is that downside compared to never starting it all winter?

One argument against might be that it will overheat since it's not being cooled by air.
But, what if you watched the temp gauge and you shut it down once it went over normal operating range?

Another downside might be that the car runs cold for a longer duration.
If you were driving, it would warm up faster, so engine is running while cold for X minutes.
If only idling, it warms up slower, so engine is running while cold for X+Y minutes.

[whiz05403]

Most say option C. I have been doing that for years now with no issues. I keep a tender on he battery.

[Coastr]

Originally Posted by sugarwood

A) Run for 5 mins.
B) Run for 15-20 mins.
C) Not starting it for 4 months.

Can we rank them? Assume actually driving the car for 20 mins is not an option.

Everyone agrees it's bad to just start it for 5 mins since it's not warmed up, and condensation is not burned off.
Well, what if you start it and let it idle for 15-20 mins so it does get warmed up?
What is that downside compared to never starting it all winter?

One argument against might be that it will overheat since it's not being cooled by air.
But, what if you watched the temp gauge and you shut it down once it went over normal operating range?

Why would an idling car overheat in winter?

I would opt for a short drive if there was a fine day in the midst of winter with dry roads.

[porsche930dude]

I think starting it is best. wait for a warm day. Keeps oil on the seals and everywhere else and the fuel from getting old in all the lines and gives the battery some exercise. When they sit for too long oil drains away from the steel parts and that exposes them to moisture and rust. 4 months isnt that long but I dont like to wait more than a month and a half or so. Iv been stretching it longer these past few years and now im getting oil leaks.

[Bob Kontak]

Originally Posted by sugarwood

Well, what if you start it and let it idle for 15-20 mins so it does get warmed up?
What is that downside compared to never starting it all winter?

One argument against might be that it will overheat since it's not being cooled by air.

You cannot really warm your car to op temp if idling in winter. The thermo to the front will not open.

Your car will not overheat if idling. Many, many hundred of liters of air per minute is run over the cylinder and head fins as well as through the engine oil cooler.

The deal is you do not get your car to full op temp and it does not allow the cooties in the oil to burn off.

I remember reading years ago that you change your oil in the late fall. Run it for a few minutes then shut it down. Before start up in the spring, change the oil again. Overkill? Perhaps.

I have owned my 81 for 19 years and have had many long idling sessions in cold weather without an associated brisk run. If there is a downside, I have not seen it.

[wrxnofx]

The biggest downside that I've read by just letting it idle is that the oil pressure is low.

[rwest]

I'm with Bob, I try and run it about once a month in the winter, when outside temps are above twenty; I let it idle for about a half hour and that gets it to over 170. I do keep my garage at 40 degrees F, so the oil isn't too thick.

I've been doing this for over twenty years on this car with no issues, so I'm not about to stop now. If it was that bad, it should have failed a long time ago!

[PrimeMvr]

I'm in the let it sit camp. I don't think starting it hurts as long as you get it good and hot, but I don't think there is any benefit to it either. I also subscribe to the change-oil-before-hibernation theory. Not because I have any empirical proof either way, but it makes sense to get as much bad stuff out before storage. Real scientific I am Battery tender is a must.

[Noah930]

C.

A is the worst thing you could do.

B may circulate fluids, but not sure it's worth the effort. When I lived in the Northeast, fogging the cylinders was part of my routine when pickling my bikes for the winter.

[Jcslocum]

Most def C is the best option. New oil before sleep keeps the acids and other nasty stuff from doing damage over the winter and you can start fresh without having to do it in the spring.

The issue with the idling is blowby and the acids. All you do is make more. I'm not a cylinder fogger but many do. I am a sea foam guy for winter storage so the fuel system stays ok.

[tobluforu]

My car sits in an unheated garage in Chicago, unfortunately, all winter long. Last year I attached the battery cables and it fired right up, could not believe the battery held a charge. Granted it was weak as hell and I ended up charging it up anyways. No idea what is better or not, but most say that its best now to start a "newer" car and drive right off with out letting it sit and idle. No idea if this pertains to older cars or not. To each their own I guess.

[Ronnie's.930]

Originally Posted by wrxnofx

The biggest downside that I've read by just letting it idle is that the oil pressure is low.

Engines do not need much oil pressure when running at idle RPM . . .

And as Bob and several other people noted, the only "bad" thing about starting and idling the engine in winter conditions is that common oil contaminates, such as fuel and water/condensate (cooties = Akron Ohio speak!) will not get burned off regardless of what your oil temp gauge indicates.

Personally, I would not start and idle an engine as some sort of winter storage, maintenance routine, but I would also not be concerned if I needed to do so for other reasons (like when repairs or mods were made).

Also, the pre & post winter storage oil changes that Bob mentioned reading about = hogwash (harmless hogwash, BUTTofcourse, but hogwash none the less)!

Originally Posted by tobluforu

No idea what is better or not, but most say that its best now to start a "newer" car and drive right off with out letting it sit and idle. No idea if this pertains to older cars or not. To each their own I guess.

I learned from my auto mechanics teacher back in 1985 (and he was in his 60s at the time), and every subsequent mechanic that I have known since then, that it always has been, and always will be better to start and drive off right away since it is preferable to warm things up quickly rather than slowly (less condensate build up in the crankcase, exhaust system, etc, and excess fuel from cold start enrichment is also cleared out much more quickly that way).

[chris_seven]

The amount of heat generated and the rate of warm up are simply dependent on the Horsepower being produced by the engine.

At idle the power developed is very low and warms up rates miserably slow.

I have never let engines warm up by idling and totally agree with the ' start them up, drive them away as soon as possible but don't drive them hard or even worse let them labour school of thinking. They will warm up much more quickly and much more evenly.

[CCM911]

I have done selection "B" for the fifteen years I have owned my 911, and there have been no bad reactions. Actually, I let it idle until the temp is at proper operating temperature.

Never had a problem.

[bpu699]

I also start it every month or so, idle for 15 minutes or so, occasionally stepping on the gas a bit...

1) Keeps all the mechanical bits moving...
2) Recoats the internals with oil
3) Circulates the antifreeze (not on a 911 obviously )
4) Turns the gears in the trans/oils them
5) Burns off any condensation in the exhaust
6) Exercises the alternator
7) Exercizes the air conditioning
8) Moves the oil around, especially if the additives are starting to settle

Plus... I get to see that the car still runs .

If the temp goes up to normal, why wouldn't that burn off condensation? How does sthe car "know" its being driven, vs just sitting in the drive way?

[ant7]

Its usualy C for me!
A...

[tharbert]

D) I just wanna hear the darn thing run.

[diverdan]

The engine needs to get hot enough to get rid of the moisture in the crankcase, combustion chambers and the exhaust. I'm a believer in option C. However, I've been thinking that the best option might be rolling the engine over on the starter enough to circulate the oil. I always remove the batteries for safety.

[911SauCy]

C.

Your car can't tell time.

[david c.]

Be honest with yourself. Why are you debating this? I think if you eliminate the "I want to play with my car" psychological component, and do the research on the effect of start up stress (particularly when cold) along with the reality that you don't get the engine hot at idle, you'd conclude C is the only logical answer. But if it sits in your garage all winter, it must be a toy/pleasure car, so if you feel like going to play with it then by all means do whatever floats your boat. It's your car.