Hot or Cold

[MiketheEngineer]

I am about 1.5 miles from the main drag when I leave my house on these cold winter mornings. Will my truck F150 heat up faster if I drive 30 mph (the speed limit) or 60 mph. (Illegal) But at 60 I will get there twice as fast.

Just wondering which scenario will get my heater working faster??

 

[dgallup]

Faster at 60 for sure.

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[IRstuff]

60, but you'll not need it for as long, either

TTFN
faq731-376

 

[patprimmer]

At 60mph you will still spend less time feeling cold, unless the destination is cold.

Regards
Pat
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[SomptingGuy]

If it's a rental, drive with the brakes on.

- Steve

 

[SomptingGuy]

Doesn't it also depend on whether it's a throttled engine or not? If driving at 30 it's forcing the engine to run inefficiently, the heat may well be pouring into the cooling system rather than the axles.

Trying to get my diesel to heat the interior takes ages at idle.

- Steve

 

[MintJulep]

On cold mornings I'm really happy to have heated seats.

 

[SomptingGuy]

Walk out to car AM with coat, gloves and scarf.
Open car (if possible).
Start car.
Scrape.
...
...
Listen to radio.
Wipers (bu88er, still not defrosted).
scrape.
Start driving.
After 10 mins, take off hat.
After 10 more, gloves.
Stuck in traffic, unbutton coat.
...
Arrive at work with car in perfect running condition.
Switch off and start again.




- Steve

 

[patprimmer]

Walked out to the car a few days ago. Looked for smoke on the horizon, checked for reports of road closures due to bush fire, cranked A/C up full then would not stop unless in the shade, left windows down a bit and sun roof opened a bit when parked.

And it was only 47 deg. Oh but that was Deg C

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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for site rules

 

[dgallup]

SomptingGuy - My 5 years experience dyno testing diesel truck engines says the higher the engine speed the faster it warms up. You will also be putting more load on the engine at the higher road speed so that will also speed things along.

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[SomptingGuy]

Exactly, unthrottled engines are just too effiecient, you need to create some serious load to get the fuel to flow (and 1/3 of it to heat the interior).

- Steve

 

[Tmoose]

I avoid the highway and drive gently for a couple of miles to let the engine warm up its juices.
Most of my 1975-1996 Volvos show some temp on the gage and have started to blow warm-ish air at the mile marker even when sitting outside all night < 32 F.

 

[NormPeterson]

Agreed (↑↑↑). I wouldn't ever take a car straight from cold start to 60 mph regardless of season or legality.

Mike - my sympathies if your engine is the aluminum-block 4.6L V8.

I'd start my car, set the seat heater and defrosters on (fan speed high) and go back in the house to do the last few things - brush teeth, put weather-appropriate jacket on, grab lunch and other stuff, kiss wife goodbye.

Usually by then the windshield would have become mostly clear and the wipers could take care of the rest. But it would still take over a mile at 25 - 40-ish mph for the coolant temperature needle just to struggle off the cold peg.


Norm

 

[crerus75]

I noticed the slow-to-warm problem on my 4 cylinder Ranger. Cabin heat took forever, and the needle on the temp gauge rode a little lower in the winter than in the summer. A coworker with a Ranger noticed the same thing. Turns out we had both used aftermarket thermostats (NAPA house brand) when we flushed our cooling systems. I put a Motorcraft thermostat in and the problem corrected itself. They both had the same temperature rating, but either NAPA had a bad run of thermostats or there was some difference in the design. Not an issue unless you've changed thermostats, I know, but I thought I'd mention it because it drove me nuts for an entire winter.

 

[RossABQ]

A block heater turned on an hour before departure is the absolute best solution. The tank type that "percolates" will get an engine up to 100 degrees in about 15 minutes. 1500 watts x 15 minutes @ 10 Cents/kWh = 4 cents electricity.

 

[dgallup]

Used to do cold start testing in Finland with a German auto manufacture. The test procedure was to let the vehicle sit out overnight then get in the car, start it and immediately floor it to at least 60 mph. I don't recommend doing this on your own vehicle but never experienced any problems.

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[MiketheEngineer]

Actually tried it both ways and seems not to make much difference. Going faster heats it up quicker BUT it takes half the time to get to the main drag.

Maybe I will just stay legal......

 

[Compositepro]

A bad thermostat (leaking or stuck open) would dramatically affect warm-up time. Check the temperature of the upper radiator hose or top of the radiator as the engine warms-up at idle. If the radiator is getting warm before the engine comes-up to temp., the thermostat is leaking.

Remote car starters are popular for pre-warming cars in cold climates.

 

[dgallup]

You only asked for time based result, not distance based.

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[140Airpower]

dgallup, in Finland? sitting out overnight? immediately flooring it? no problems? no problems, ...yet?
This reminds me of a neighbor whose warmup procedure was to start it up cold and rev it to about 5,000rpm repeatedly for about 5 minutes. Good engine, for a while.