Warming up the car before driving
 

Was flipping through the the manual before I erased a CEL code with my new Actron reader and I noticed under 'starting the car' that it was not recomended to warm up the car before putting it in gear. Instead it said you should just start it up put it in gear and keep the revs under 4500K for five minutes.

Does anyone who actualy does this find this strange? I thought the engine temp should be allowed to come up so as to avoid engine wear?

Huh? Are you telling me you let the car warm up to operating temp before driving it? That would take at least 20 min. I just do what the manual says and keep the revs low until it reaches the proper temp.

Yeah - you allow engine temps to come up by driving the car, albeit gently until it reaches normal operating temps! Think about what your are trying to achieve by letting the car idle without driving it - you want to get it to operating temp asap; but by trying it that way, you are ensuring that the motor spends much longer running BELOW normal operating temp - exactly what you want to avoid, since that is what can cause wear.

To warm it up quickly and properly, start the car and drive away promptly. Don't rev hard or use heavy throttle until the needle's where it should be. :cheers:

no not 20 minutes, more like however long it takes me buckle up adjust mirrors, plug in the V1, maybe wipe the inside of my plastic rear window. The iddle usually comes down from slightly above 1000 RPM to idling just below 1000 in a matter of 3-5 minutes depending on how cold the weather is. Some days up here in NY/NJ this winter when it was 12-15 degrees farenheit I definitely waited at least five minutes before putting my Boxster in gear.
Turning on the ignition when its 20 degrees below freezing and imediately dropping the car into first gear sounds crazzzzy to me.
But if that's what Porsche recommends I'll do as they say.

A couple of minutes warm up in cold weather is a prudent move. However, the car will warm up faster if you drive slowly.

I say, take that minute or two when it is as cold as you say it has been.

Also, until the car is up to op temp, drive easily.

I try to give it atleast 5 mins or so to warm up in my driveway if it's the first time being driven all day. I can't see it causing any harm. Alot of car people do this... especially in colder weather.

I really think the most important thing concerning warming up is to be very gentle on the engine until it is fully warmed up. You will extend the life of the engine by following this rule. The oil cannot sufficiently protect the engine until it is warm and dispersed evenly on all the moving parts. I learned this the hard way when I hot-rodded my old 528i when it was cold. Broken lifters aren't fun. My dad's M5 has nifty little lights on the tach that gradually disappear to let you know the safest maximim engine speed as it is warming up.

Adam is so right. In addition, in those Northeast Winters, you might try using Mobil 1 0-30MPH. Should help you get a bit of extra MPG also.

why doesn't Porsche just say "let warm up for a few minutes in extreme cold"?
Instead they say drive the car right away, no exceptions mentioned.
I'm thinking there must be some rationale for this.
Perhaps Porsche believes that an engine sitting at idle is worse than cold moving parts.

I'd say your fine either way..just use your best judgement.

Not that I know anything about thermodynamics, but I suspect the Porsche recommendations (and they are not alone in these recommendations) have to do with the aluminum alloy block and heads, the viscosity of synthetic oils at low temperature, and maybe even the way the fuel mixture is maintained by the ECU.

Since aluminum transfers heat much better than a great lump of cast iron, I suspect the engine block and heads come up to operating temperature very quickly. Modern synthetic oils also maintain their pourability a very low temperatures, so there is less need to actually heat the oil a whole lot before putting the engine under load.

Computer controlled fuel mixtures and ignition settings also reduce the old problems of excessively rich or lean mixtures dependant on temperature, so engines just run better when cold than they used to.

I agree with that fully, new engine materials and design changes conventional wisdom.
Now what's to be said about Porsche warning against an engine sitting at idle for a few mintues?
Is there some danger that this practice done on a daily basis could lead to problems down the line?
I'm going to check with my service manager and see if he's heard anything on this topic.

Yes, because as I said, by letting it sit for a few minutes, you are prolonging the period in which your Porsche engine operates BELOW it's normal operating temperature. Starting it up, quickly followed by gentle driving is the quickest way to get your motor safely, up to operating temps, which is what you're aiming for.

Every owner's manual I've ever had previously - (all were VWs and Audis), have recommended this method, for fuel economy as well as engine longevity. Had nothing to do with materials either, they were all iron-block motors and ran on mineral oil from the factory.

Perfectlap, do not forget you are reading a manual written by a large company in Germany who is working very hard to be politically correct and ecologically sensitive.

Germans are sticklers on clean air nowadays (didn't use to be like this, but the damage caused to the black forest by automobile fumes changed everything) and I would not be surprised they put this in the manual just to cut down on the amount of exhaust fumes in the air.

Read any greenie's list of things to do to save our planet and you'll see right up on the top of the list:

"Do not warm your car before driving it. This causes unneeded pollution."

That's my read on this... we could toss around mechanical and performance and long wear comments all day long, but in my opinion, it's all about keeping the conservationists happy.

(Note: Conserving natural resources and protecting our environment is important to me! I'm just stating why I think that line is in the manual.)

^That is true. I don't think I've read any car manual that recommends letting your car warm up first. It definately isn't harmful to your engine though, the slower your engine warms up the better. The danger isnt in having it operate at low temperatures but having the temperature rise at a high rate because all of your seals, etc. haven't had time to adjust.

^ I have to disagree with you PorscheKid. You want the engine to warm up as quickly as possible like john said. I think your logic is flawed no offense.

when the car is started for the first time on a day it is good to let it idle for mebbe 5 minutes. In doing this it allows to heat up and lubricate the parts properly. Then drive off taking it easy until the temperature comes up. When driving straight form a cold engine, taking it easy will reduce damage but warming it up a little bit own't hurt. The most damage to an engine is during start up - and that is because the oil does not sufficiently lubricate right away. Hence the invention of oils such as Castrol Magnetic which claims to "stick" to parts to avoid this initial wear.

Warming up too fast = hot fluids in a cold engine with cold seals which is not good. It's the same principle as keeping the rpm's low when starting out. The cooling system in a car is sufficient to warm it up when you start out. Only disadvantage to warming up is that a cold engine burns more fuel (wasteful and worse for the environment.) Even when warming up you want to take it easy when starting out because your tranmission fluids also need to warm up while driving. I'm not saying to let the car sit for 10+ minutes but 2 minutes or so (especially when cold out) is good for your car. Older cars benefit more but the principle remains the same.

Where does that "hot fluid in a cold engine" come from? You don't mean the oil or "coolant" do you? :rolleyes: :D

The worst time for the engine is the microseconds while you're cranking it but it hasn't started yet - because oil pressure is low and the rings are scraping what little oil is left on the cylinder walls off. Everything after that is a breeze in comparison, so long as the oil pump is working OK. I pause just long enough for the top to lower or the attractive chimes to stop and then I'm off...

In the extreme cold, I see widom in allowing the engine oil to circulate a bit. By that I mean, a minute or two seems prudent. Driving easily until full engine temps is also prudent.

Lastly, in very cold weather, a clean quality synthetic is a must. Personally, if I lived again in NE, I would use 0W-30 syn in winer. Then again, if I lived there again, I would start drinking heavily again!

:D