Cold Weather Advice

[71Beige280SL]

This is the first winter I have owned my 71 Pagoda. In preparation for the cold weather, I rented an auxiliary garage to shelter my baby. When it came time to put the car away for the season, I couldn't bring my self to do it! I enjoy walking out into the garage, tinkering with the car and doing small projects. My guess is none of you are surprised by my separation anxiety!  My 2010 E550 drew the short straw and spends time in the the auxiliary garage. Funny how things work!

Now for the question...A Mercedes mechanic told me that it is not good to let the car idle for very long...carbon build up...rough on the points, etc. (I am going the Pertronix route in the spring). This car will never see rain, snow or salt and as such, never drive it in bad weather. When the weather keeps the car in the garage, I like to start up the car at least once a week to keep everything lubed. With the voice of the mechanic in my head, I start the car, engage the hand break, slip the car into neutral and gently rev the engine. I vary the RPMs until the car comes up to temperature. First, is my mechanic correct? Will this once per week practice cause any issues?

Thanks!   

[mdsalemi]

Your mechanic is quite right .  if you start your car, you need to warm it up and run on the road.  If you can't do that , probably best to not start it at all.
My car generally sits (with fuel stabilized and tires pumped up) from sometime in November through mid-April.  On occasion, when I have visited my storage (garage at 2nd home) in the winter, and the roads are DRY (no salt is used in the lake area), I will take it for a run.  That run is a good 30 minute, everything warmed up run.

That being said, it is only happened about 3x in 10 winters of storage.  Other times, it is just left alone.  I don't put a battery maintainer on it since I don't like anything plugged in when I'm not there.  Months can go by when I'm not there.  If you store in your home garage, that's a different story.  My MB battery lasted from 2004-2010, and in 2010 was still holding about 80% charge when full.  That's fine because--the car isn't used in the winter!  

[Iconic]

I have heard it is not good to start the car unless you will drive it and get everything fully warmed up under load.
Now, that being said, I would like to hear what the experts say about all this.
If you run your engine as you describe, I realize the transmission and rear end are not doing any work, but isn't the engine fully warmed up if enough time goes by?
I've heard that idling allows acids to build up in the oil and I believe, as it cools, moisture condenses in the oil or in the engine. And, on some cars, idling doesn't get the oil hot enough to evaporate off the moisture (although these cars seem to get right up to temperature). But, if we are varying the RPMs, aren't we in fact sucking vapors out the valve cover, which is the intent of the vent at the top (I believe); To pull off these acids (and moisture) that come out as a byproduct of the engine running?

Having said all that. Maybe there is also no good reason to start the engine for a 3 to 5 month hibernation ....... except I like the idea of moving the fuel around.
If it is true that we should not run the engine unless we are driving it (to full operating temperature), then what do you think of this?
Simply once a month or so (once a week if you must), just turn on the fuel pump for 30 or 45 seconds to get the fuel circulating through the system and get fresh fuel in the pump, FIP, lines, etc???
What do you all think? How much of this is stuff that I erroneously learned as an eighteen year old and never re-learned as I go older?

[twistedtree]

Although I agree the best thing to do is start and take the car for a drive, that's not always possible.  Given that, I'd think that starting and running a little bit is better than letting the car sit for an extended time period.  3 months feels like the break point, i.e. I'd leave a car for 3 months without starting, but if it were longer than that I'd run it every few months.

[thelews]

Yes, you're building up a lot of moisture when you start it up and idle/rev up to water temperature.  It's really quite bad for the car, gas, condensation in the oil, condensation sitting in the entire exhaust system.  If you can't get the car out and really warm, that means the oil, so that you burn off moisture and are also effieciently burning fuel so you're not dirtying the oil, then don't start it at all.  That's at least a 1/2 hour hard ride in cool weather.

Once my cars are shut down for the winter, that's it.  The cars are run until they're good and hot, then the oil immediately changed so the car sits with fresh clean oil on all parts, then tucked away with a battery maintainer.  Start up in spring and go, no issues.  

What you're doing is worse than a good sit with fresh oil and a maintainer.  In fact, in my opinion, it's downright harmful.

Just my opinion and experience.

John

[Jonny B]

I would concur that the best thing to do is to take the car out for a drive if possible, get it fully warmed up, and that means the oil, as the others have stated. The products of combustion include water and acids, and not letting the oil get hot enough to drive those out, is a bad thing. Also if water is allowed to accumulate in the exhaust system, you are asking for corrosion there from the inside out.

Do all the storage things, put stabilizer in the fuel, pump up the tires, and say "Good night" until spring.

When I was in Ohio, that is what I did for 7 winters, with no issues in the spring.

[Richard Madison]

You saw my 69 Tunis Beige 280SL at PUB last year.

I don't use the car in Winter but I do take it for a drive every few weeks.

I leave the battery connected since it seems to draw very little.  I wait for a day above 40 degrees if possible (for my comfort, the car doesn't mind cold weather).  I avoid salty roads after a snow.

About every 6 or 8 weeks beginning in November, I take the car out. I make sure it fully warms up and I wind the RPM's on the high side (at least 4,000) to keep the juices flowing and the battery charged.

I get on a local highway and drive for a while in third gear (manual tranny) to make sure the higher revs burn out all the junk.

I've done this for many years and it seems to be a good routine for me as the car is always ready to fly in April.

This same high rev driving can also help in warmer weather when the car gets a bit sluggish or runs rough especially after some city stop and go driving...high compression engines need a good blow out from time to time.

Richard M, NYC

[71Beige280SL]

Thanks for the advice. My take away...let it sit (with fresh oil) unless you can get it out on the road for a good 30 minutes+ at high RPMs.

[thelews]

Thanks for the advice. My take away...let it sit (with fresh oil) unless you can get it out on the road for a good 30 minutes+ at high RPMs.

Don't forget Stabil in the gas.  Let it mix and run it through the engine for at least five minutes.

John

[menesesjesse]

I agree with john. Take the car out for at least 30 minutes of driving or just store it. Im a believer of exercising the car but an idle for 15-30 minutes is not enough. I did this last year and the left over condesation mixed with the oil and it looks milky if you do that on several occassions. Best to take it out and drive it throughly so everything burns off and nothing accumulates within the fuel and oil systems.