warming up your car

If the lubricant has to take a couple of minutes to get all around the engine, your engine would seize in short order. Once oil pressure is up, which is about 5 seconds after starting, you are good to go.

With older carbureted vehicles it was not uncommon for the cold-start systems like the cold air heater, the choke, and such, to get wedged, rusted, or non-functional, so the engine generally was running on a very suboptimal fuel mix for the first 15 minutes or so, and on cars that had screwed up cold start systems, it was easy to stall them during warmup.

With efi systems, the computer takes care of the cold start mixture and actually driving it makes it warm up even faster than just idling.

Ted

Drive off as soon as the engine runs smoothly, but go gently with the gas pedal until it reaches normal operating temperature. The corrosive by-products of combustion and water vapor are what do the most damage so the quicker it warms up the better. Avoid prolonged idling like the plague while it's still cold -- normal engine speed will also throw a lot more oil at the cylinder bores.

Same deal, except it will probably run smoothly sooner. You'll also reduce exhaust emissions by having it warm up quicker.

The length of time you need depends on:

1.) Outside temperature. 2.) Length of time the vehcile has been sitting. 3.) The larger the enigne, the more time to needed. 4.) Type of engine and drive lubricants. Synthetics take less time. 5.) Diesels take more time than gasoline engines. For more information, Google search for "warm up time for engine" and for synthetic product options.

snip

I wonder why that would be. Does synthetic oil have a significantly different specific heat, or does it have to run at a higher temp?

No. In fact is bad for your car.

Minutes? Oil gets circulated in seconds, not minutes.

Makes no difference.

----------------- Alex

I was always under the belief that warmup was primarily to warm manifold up to get better drivability (with carbed cars) and to allow expansion of clearances to more normal values, to cut down on fuel into crankcase and to keep from beating bearings with excessive clearances. That took a bit longer than circulating oil.

Now, my understanding is that driving gently (keeping rpms and bmep down) is better, and keeps from pounding bearings, till temps come up.

You may or may not be aware that large diesel semi-tractors can have a "Pre-Oiler" that when swiched on prior to start-up, will circulate the engine oil in order to have the "pounding bearings" and pistons lubricated before the engine is started. This gadget is useful during extreme cold, i.e. minus 20s & 30's but during the summer not crucial but handy to have.

The quote: "I wonder why that would be. Does synthetic oil have a significantly different specific heat, or does it have to run at a higher temp? " has not had a reply. When you compare engine oils in catagories, i.e

1.) Pour Point, Cold Temp. Start-up 2.) Volatility, for fuel consoumption and emissions These show that superior synthetics out-perform conventional engine oils.

Get in, start the car, then drive like you had an egg under your foot until it warms up.

"NickySantoro" wrote

You mean you don't hop into your 80's Chevy Suburban with the bad muffler, start it up, let it idle normally for about 3 seconds, then rev it up to 4000 or so and hold it there for the next 5 minutes, at 5:00 o'fricking clock in the morning? That's what the guy across the lane from where I used to live did. Lucky for him, I moved before my permit to carry a concealed rocket launcher was approved.

On Mon, 03 Apr 2006 09:20:38 GMT, "MasterBlaster"

We had a Laotian lady up the street from us years ago that started her 4-4-2 that way about 5 every morning and held it there for at least a couple of minutes. After a couple of years, I heard a loud noise when she did this. I looked out the window and saw a huge cloud of smoke and steam and the engine wasn't running. After that, I could sleep a few minutes later.

Lugnut

I am not sure that these factors, taken as you have presented them, prove the superiority of synthetics.

I b elieve a thorough warmup is less important than it used to be. In the old days, engine clearances and materials were less conducive to long engine life than they are now.

Carburetors often tended to run very rich during cold choke conditions, and the engines would stumble and protest until well warmed. (Sometimes afterward too.) They could be dangerously unresponsive under today's driving conditions.

Oil was often diluted by raw gasoline, which really didn't help anything either.

With modern engines, fuel injection makes the engine run smoother under a wider range of conditions--- and when you have developed oil pressure (usually within a few seconds after you start up), you are good to go.

In cold weather, your heater will take a while to warm you up, but your car will get along just fine.

That's what I do.

---------------- Alex

I'd basically agree, except that its not so much the bearings that you're protecting. Running a cold engine gently is most important for the cylinder bores, because piston-to-wall clearance is the single engine parameter that changes *most* from a stone-cold engine to normal operating temperature. Bearing clearances don't change nearly as much.

I've done some reading that suggests that ZDDP antiwear additives have a certain activation temperature. Getting the oil up to temps faster should speed up the process. Of course there's probably a point where you're doing more harm by stressing the lubrication by (let's say) revving the engine before the oil has reached its ideal temps.

I don't know about a "standard" or if there is one, but I turn the key on, let the pump

feed the injectors, start the engine and wait for all the test lamps to go out, then

drive off at a slow rate of speed and continue on slowly until it is necessary to speed up.

I prefer not to let the engine - just idle - for the hell of it.

There probably isn't much likely damage - unless one is tempted to start and gun / rev the engine unnecessarily, I think.

mho vfe