Engine warm up poll.

[Tallpine]

What you're forgetting is the transmission and the axle gears. The engine generates heat quickly due to the combustion -- the gears only warm up due to friction. It's important to drive not just slowly but also gently for the first several miles in cold weather to allow the gear lube (which is a lot more viscous than motor oil) to start moving around.

Driving a pickup or RWD around a small town in sub-zero weather you almost never have to touch the brake pedal 

Let off the gas, and the cold oil in the gearboxes stops you right now!

[K Frame]

When my Father died was the last time I was driving when it was REALLY cold. A couple of days it dropped down close to zero.

I was driving the old Subaru, and it was nearly impossible to move the shifter or push in the clutch everything was so freaking cold.

[Balog]

If it's cold I generally warm it up while scraping the windows. If it's not cold I generally don't.

[Tallpine]

A couple of days it dropped down close to zero.

Yeah, but what about when it gets cold 

 

[brimic]

When my Father died was the last time I was driving when it was REALLY cold. A couple of days it dropped down close to zero.

Lolz, 'REALLY cold' starts at -40, and I'm very happy that I no longer live in an area that experiences those temperatures.  
As my Dad used to say- things break really easily at those temperatures and its too damn cold out to fix them when they do break.

-----------------------------------------
Start it up and go. Don't 'drive it like you stole it' until the temp guage gets above 100.

[Tallpine]

I don't suppose anybody on APS but me has ever used a mix of sawdust and diesel in a coffee can under a truck or tractor or sawmill engine to warm it up enough to even get it to start?

 

[K Frame]

"I don't suppose anybody on APS but me has ever used a mix of sawdust and diesel in a coffee can under a truck or tractor or sawmill engine to warm it up enough to even get it to start?"

Think again.

[Jocassee]

I flog mine like a stolen horse as soon as it starts.

[drewtam]

"Drive it like you stole it" is misleading, nobody is going abuse something that they need to sell quick.

"Drive it like you rented it", now that is abuse.

[Jocassee]

"Drive it like you stole it" is misleading, nobody is going abuse something that they need to sell quick.

"Drive it like you rented it", now that is abuse.

I think the connection is that if you steal a car you'll need to be hauling ass to get away from the Popo. At least that's what I do when I steal cars

[Balog]

"Drive it like you stole it" is misleading, nobody is going abuse something that they need to sell quick.

"Drive it like you rented it", now that is abuse.

Drive it like it's a free loaner from a mechanic's shop while they replace your water pump. On an entirely unrelated note, Smart cars with the flappy paddle gearbox are a lot of fun when you never shift before redline... 

[Tallpine]

"I don't suppose anybody on APS but me has ever used a mix of sawdust and diesel in a coffee can under a truck or tractor or sawmill engine to warm it up enough to even get it to start?"

Think again.

Somehow I never thought of you as the sawmill slave type 

[K Frame]

Worked my way up from the galley.

Friends had a kerosene tractor that was a beast to start if the temperature was under 45.

[Tallpine]

Worked my way up from the galley.

Friends had a kerosene tractor that was a beast to start if the temperature was under 45.

That's amazing 

You had friends 

 

[K Frame]

Yeah, that tractor and I were tight.

The others were just surplus organs in case the tractor crushed me.

[Perd Hapley]

So how cold does it have to be outside, before one ought to give a car a few minutes to warm up? I tend to do it if the temp is below 50.

If things are below that temperature, and you get to your destination, how long can the car sit before it will need to be warmed up again (to go someplace else)?

[Tallpine]

So how cold does it have to be outside, before one ought to give a car a few minutes to warm up? I tend to do it if the temp is below 50.

If things are below that temperature, and you get to your destination, how long can the car sit before it will need to be warmed up again (to go someplace else)?

A modern car with FI and aluminum block, I wouldn't worry about it until the temp gets below 20 F, unless you live two blocks from the freeway and are going to be immediately up to 70mph.

Parked, I'd guess it would be fine up to a half day or so depending on how cold it is.  If it's -40 then yeah it's going to cool off pretty fast.

With my old old pickup, I've found that it can actually warm up while it sits.  So sometimes I will start it and stay there with it and idle it a couple minutes, and then shut it off and go back into the house for a while.  Maybe ten minutes or so later, I go back out there and re-start it and by that time the combustion heat has spread through the whole engine and most importantly into the intake manifold and carb.

Back in the old days, I would have to warm up my old truck (gas) even on a summer morning in the mountains before heading out with about 25K # gross. 


One thing that I've discovered is that with FI vehicles, they start real good down to about -20 F but below that the computer seems to get all confused and can't figure it out.  An unheated carb engine with a choke will usually start down to -40 F or below (at least my Chevy/GMC pickups/trucks always would, assuming the battery would handle it).

[AmbulanceDriver]

One thing that's interesting about my truck is that there's an intake air heater that kicks on if the air temp is below (I think) 50 F...  And stays on until the engine warms up sufficiently *or* you're driving in excess of 20MPH.   

HOLY CRAP...  Just looked up the specs on the heaterS (yep, 2 of them)...  EACH heater draws 95 amps at 12V....    Dang...  Combined for just shy of 2300W...  No wonder my voltmeter drops when that thing cycles even when the engine is running...   190 amp draw is.... Impressive.

[drewtam]

One thing that's interesting about my truck is that there's an intake air heater that kicks on if the air temp is below (I think) 50 F...  And stays on until the engine warms up sufficiently *or* you're driving in excess of 20MPH.   

HOLY CRAP...  Just looked up the specs on the heaterS (yep, 2 of them)...  EACH heater draws 95 amps at 12V....    Dang...  Combined for just shy of 2300W...  No wonder my voltmeter drops when that thing cycles even when the engine is running...   190 amp draw is.... Impressive.

Sounds like an intake air heater for a diesel. If diesel, then it is not so much for warming up the engine as it is to improve cold start and prevent white smoke. It is one of the major alternatives to glow plug or ether aid.

[Nick1911]

One thing that's interesting about my truck is that there's an intake air heater that kicks on if the air temp is below (I think) 50 F...  And stays on until the engine warms up sufficiently *or* you're driving in excess of 20MPH.   

HOLY CRAP...  Just looked up the specs on the heaterS (yep, 2 of them)...  EACH heater draws 95 amps at 12V....    Dang...  Combined for just shy of 2300W...  No wonder my voltmeter drops when that thing cycles even when the engine is running...   190 amp draw is.... Impressive.

Very impressive.  Assuming a big engine, say 7 liters of displacement [every 2 rpm], idling at 750 rpm, that works out to a temp rise of 78F for incoming air.

[zahc]

One thing that's interesting about my truck is that there's an intake air heater that kicks on if the air temp is below (I think) 50 F..

I assume this is a diesel. Typically for a gas engine, you want intake temperatures to be as cold as possible.

[Tallpine]

I assume this is a diesel. Typically for a gas engine, you want intake temperatures to be as cold as possible.

Yeah, that's why they started putting those ducts from the air cleaner to the grill.

[AmbulanceDriver]

Very impressive.  Assuming a big engine, say 7 liters of displacement [every 2 rpm], idling at 750 rpm, that works out to a temp rise of 78F for incoming air.

It's a 5.9 liter engine...   So while I don't have the equations, I know that this increases the temp rise....  :)

What's really amazing is the fact that at a 17.0:1 compression ratio, The air temp at TDC is *HOT*...   Making some basic assumptions - moderate boost on the turbo giving me 2 atmospheres pressure at intake...  And assuming a *really* good intercooler that knocks intake temp back to 100 F...  At TDC, the air temperature goes up to almost 1300 F....


Man I love diesels... :D

[230RN]

Subaru Outback 4-cyl boxer engine. 

Warm weather or cold, I start it and fiddle with things for about 30 seconds.  Then I slowly drive it out the long driveway, usually stopping by the dumpster (about 200 ft) for about 30 sec to dump the trash.  In the meantime, since it's idling fast in the warmup stage, I regulate a low speed by going in and out of Drive.

By the time I get to the street (another 400 ft), the idle's gone down and I take it easy pulling out and getting to about 30.  Will not pull out until the road is perfectly clear, so I don't have to punch it.

A long time ago I read somewhere that most engine wear was at startup, and I always intended to bugger up the ignition switch on my '72 240Z so that  it would crank without ignition for a few seconds to get the oil pressure up a little before lighting the fires. 

Never got around to it though.   I broke the car before it broke me.  Engine at 280Kmiles  was in fine shape, compression a tad low on #1 cylinder... bearing in mind that one normally gets slightly lower compression readings overall at this altitude. 

Terry

[geronimotwo]

i voted for the "drive normally".   of course, when i was instructing a helpfull youth on how to drive my vehicle he termed the summation of my instruction was to drive "annoyingly babyishly", to which i replied, "exactly!".