The Healthy Long Winter Warm-Up

[Shannow]

Originally Posted By: SavagePatch
What are we considering long? A minute or two or until the idle rpm drops?

Does an engine warm faster with the heater set to cold and fan to off or with the heater set to hot and the fan on?

@Shannow: Are you saying that warming the engine unnecessary? Just curious...

...Thanks in advance!


The things that Merk wants to achieve are the reasons that the OEMs put in the fast cold isle in the first place.

The bearings turning at a couple thousand RPM pump create nearly 4 times as much frictional power as at 1,000 RPM (when talking bearings, think also the large surface area of the piston skirts as bearing surfaces).

See this diagramme

That particular engine/oil combo, from cold, 2,000 RPM was about 4KW of frictional heating of the oil (think in terms of putting 4KW of bar heaters under the sump)...at 1,000RPM, would probably only be 1KW. That 4KW of load also means that the Exhaust temperatures will light off the catalysts a lot sooner.

Seriously, we start the car, then belt up, then drive. In (my -5 to -11C) winters, holding the trans in "2" until I get out of town has a notable affect on the temp guarge.

So I firmly believe that getting the OP up, the engine stable in gear, and driving off are the best for all.

I'm not advocating what friend(s) used to do, a burnout from cold in the morning with 20W50, just light throttle, 2-2,500 RPM, and get the heat in there.

 

[Jetronic]

th thing is, I hit traffic with kids going to school as soon as I turn the corner. I want my windows defrosted and dry before I get there. If I don't idlethe car for a few minutes, this doesn't happen and I'm not going to see unless I put my head outside.

kids on bicycles aren't all that good with keeping to their side and with running lights...

 

[Shannow]

Originally Posted By: Jetronic
th thing is, I hit traffic with kids going to school as soon as I turn the corner. I want my windows defrosted and dry before I get there. If I don't idlethe car for a few minutes, this doesn't happen and I'm not going to see unless I put my head outside.

kids on bicycles aren't all that good with keeping to their side and with running lights...


That's all good reasoning, and I won't suggest that you change.

I park outside, and definitely run the engine while I scrape off the ice...the Nissan has a "heat" button which increases idle to 17-1,800RPM while I'm doing it.

 

[Garak]

Well, given how brutal your winters are, Merk, use an automatic starter, activating it right before you start putting on your snowsuit. By the time you get yourself all bundled up for your horrific Arctic conditions, your engine should be at operating temperatures.

 

[Jetronic]

Originally Posted By: Shannow
Originally Posted By: Jetronic
th thing is, I hit traffic with kids going to school as soon as I turn the corner. I want my windows defrosted and dry before I get there. If I don't idlethe car for a few minutes, this doesn't happen and I'm not going to see unless I put my head outside.

kids on bicycles aren't all that good with keeping to their side and with running lights...


That's all good reasoning, and I won't suggest that you change.

I park outside, and definitely run the engine while I scrape off the ice...the Nissan has a "heat" button which increases idle to 17-1,800RPM while I'm doing it.


I usually get another cup of coffee while the window defrosts. the engine is by that time still cold enough not to register any heat on the coolant temp gauge. in fact, as long as the cabin isn't on temperature and the interior heater lets off, the coolant temp doesn't get above 50°C. Not with my driving style and conditions anyway.

 

[demarpaint]

I'd replace the thermostat, and use an OEM replacement only.

 

[Jetronic]

the thermostat is fine. I've had this car since new, and it always did this. Also no dummy coolant temp gauge...

I can let it idle for an hour (from cold) and it would consume barely more than 1 quart of fuel. that's why it takes time. once hot, around half a quart per hour

this is not a big petrol engine...

 

[bbhero]

Yeah -1°C is absolutely brutal

Compared to -40°C that's like a Hawaiian vacation.

 

[Cobranut]

Your thermostat is bad. If the thermostat is closed below 195 degrees, the radiator will dissipate NO heat from the engine.

 

[Jetronic]

who are you referring to?

I agree the thermostat may be bad in Merkava's car.

Mine only sheds heat through the cabin heater.

 

[Shannow]

Originally Posted By: Jetronic
who are you referring to?

I agree the thermostat may be bad in Merkava's car.

Mine only sheds heat through the cabin heater.


Looked like to Merk from my perspective.

My playing with an inlet hose thermostat proved that even a 0C winter here, the heater and block were enough to shed all the heat my 253 ci V-8 could make at 100km/hr.

 

[fdcg27]

As others have noted, the engine will rapidly warm under load.
Load can be best applied by driving the car.
The one and only reason I warm cars up at idle in really cold conditions is personal comfort and convenience.
When ambient temperatures are below 10F or so, I'll often go out and start the cars and allow them to idle for around ten minutes. This allows enough heater output to melt the frost off of the windows as well as to warm the interior somewhat.
Other than that, no real reason not to just drive off gently from a cold start.

 

[sprite1741]

Healthy long warm up, is not correct. Something like 95% of engine wear occurs before the engine reaches operating temperature. The idea is to shorten that time. Driving it warms up the engine faster. That equals less wear and tear on the engine. Idle for 15 to 30 seconds max. Scrape the windows and drive easy for the first few miles. It saves gas and your engine. One of the first things I learned in mechanics school. So many old myths still remain. If you want to idle to warm your interior up that's your business but it is not doing the engine any good.

 

[Jetronic]

Originally Posted By: sprite1741
Healthy long warm up, is not correct. Something like 95% of engine wear occurs before the engine reaches operating temperature. The idea is to shorten that time. Driving it warms up the engine faster. That equals less wear and tear on the engine. Idle for 15 to 30 seconds max. Scrape the windows and drive easy for the first few miles. It saves gas and your engine. One of the first things I learned in mechanics school. So many old myths still remain. If you want to idle to warm your interior up that's your business but it is not doing the engine any good.


You can also reduce wear during warmup. Why is there extra wear during warm up, and what exactly is wearing faster? If you don't know that, how can you take proper action against it?

I know one thing, it's not likely the bearings experiencing wear during warm up (contrary to startup).

Or is 95% of the wear during warm up including start up?

 

[TFB1]

Originally Posted By: Merkava_4
Originally Posted By: Shannow
Is the thermostat working ?


It works fine. It's always been a cool running engine. That aluminum radiator really throws off the heat.

BUT if it's "throwing off heat" before T-stat opens the stat is bad..

Originally Posted By: Merkava_4
The computer won't take the engine off of high idle until the water temp gets up to 198 F. That tells me the computer thinks the engine's full operating temperature is 198 F.


I call B-S, no engine should be at more than normal idle after a minute or two, no matter what the temp...

I often let mine idle in winter but not for your bogus reasons, I like to be warm...

 

[demarpaint]

Unless I'm mistaken as far back as I can remember my vehicles came off high idle long before the coolant got to 198*F.

 

[SwampSurvivor]

Depends!

Before I replaced the thermostat, I would get in and drive. Even with it's annoying "I HAVE TO RUN AT 2500 RPM" high idle programming. With the bad thermostat, it didn't matter if the car ran all day ... it was never going to come up to temperature sitting.

Now, I may let it run for 3 or 4 minutes before I take off. Usually just enough for it to idle normal and not race up to 2500RPM every time I push in the clutch.

My parents go overboard. My mom idles the Escape for 30 minutes and her drive in to work is only 18 miles.

 

[mjk]

Originally Posted By: demarpaint
Unless I'm mistaken as far back as I can remember my vehicles came off high idle long before the coolant got to 198*F.


Mine typically come off of high idle at less than 1/2 way to full operating temp.

 

[Jetronic]

mine within seconds after starting, but high idle is only 100 rpm over regular idle

 

[Quattro Pete]

Originally Posted By: Merkava_4
Originally Posted By: OVERKILL
LOL at 47F being "winter"

That's at 9:00 O'Clock at night. It got as low as 31 F in the morning last week.

LMAO! Thanks for the laughs.