by Bull6791, January 6, 2015
I always wanted to know what is better
In cold weather: fully warm up car before you drive each time.
Or
Warm up car a little bit. Then drive and when you drive let your driving warm car up the rest of the way.
I just do not know what is better for car in cold weather.
Also is it a waste to let car fully warm up in cold because it waste to much gas.
Thanks
Depending on how cold it is outside and if you use a block heater, let it idle for about a minute, then drive off moderately. It'll warm up much more quickly if you don't just let it idle. Don't turn heater fan up from low until it is warmed up. Cover your front grille in front or behind it for use in sub-freezing temps.
Dom
I thought in cold weather the car should be fully warmed up before you drive the car.
Where I live it does not get that cold where I need a block heater.
It never needs to be fully warmed up before driving off... If it's actually cold enough outside, it will never reach normal operating temperature by just sitting there idling... Idling and running cold is bad for your engine. You want to moderately drive off and gradually increase your speed and rpm's to warm it up efficiently and as well as possible.
So I have actually been hurting my car all these years by fully warming it up on cold days before driving off.
LOL, it aint so bad. It's just wasting gas and carbonizing your combustion chamber and engine oil... It's much better than racing the crap out of it when it's still cold.
It's important for the engine oil to reach at least 212F at least once per day that it is driven ideally, to evaporate moisture and gases from the oil, to prevent sludge and reduce acids formation.
A lot of this depends on the car itself - some cars like to be idled first, some don't care.
Extensive idling does tend to put an excessive amount of load on the camshaft lobes - so there is a higher chance that they will wear more than an identical engine that didn't get idled as much.
But as dom mentioned - not something to loose sleep over. Engine will warm up WAY faster, once you are underway. If the ambient temps are very cold - the car may not be able to generate enough heat to warm up at only idle speeds.
Myself - don't really see much colder temps than single digits in VA. When I lived in OH, can drop down to subzero temps. But even with conventional motor oil at the time - just start the car, let the idle stabilize, then drive off normally - keeping RPMs moderate until the engine fully warms up.
Worse things you can do is idle for extended periods (20-30 minutes +) or race the engine from cold soak. In that case, the oil viscosity could be thick enough that it could burst the spin on filter canister from the excessive pressure (can't bypass enough flow to protect itself).
Warming up the car is more for the occupant's needs than the engine's need.
Fish
After starting car how do you know when idle stabilizes.
Also it turns out to be the opposite of what I have thought all along. I thought in cold weather if car was not fully warmed up and drove off all the time it would lead to muffler and exhaust problems down the road.
Thank.
You'll see it, hear it and feel it. Idle will race initially, as the ECM is programmed to fast idle to help get the fluids moving, warm up the engine - then you'll see / feel / hear the RPMs start to slowly drop. Will not necessarily drop down to steady state idle on a warm engine, but will be significantly be lower than when it first started.
Good example was this morning - ambient air temps were in the teens. Started my car - fast idle to about 1500 RPMs, then the revs dropped to about 1000 RPMs after about 30-45 seconds. That point, I shifted it into gear and slowly accelerated, refraining from WOT until I see the temperature gauge start to move from the bottom position. By the time I get to the highway, I've traveled about 3 miles in about 6 minutes and the car is pretty close to being fully warmed up.
If I had just idled the car - it wouldn't have reached that temperature even with 15-20 minutes of idling.
As for "if the car is not fully warmed up, leading to muffler/exhaust problems" - I've never heard of that. If anything, the opposite would happen - at idle speeds, the car cannot push out condensation as quickly as it could, leading to moisture building up and sitting in the exhaust system.
Fish
So really on a cold day all you want to do is start car. Wait maybe 2-3 minutes max. Then pull away. Drive slow and steady until car is fully warmed up.
Driving the car will warm it up the rest of the way.
Long idling to warm up car is bad for engine.
Thank.
All depends on how cold and the situation of the car/environment.
Even two or three minutes is not necessary - even in subzero weather. Only time I've idled that long was when I was scraping ice off the car- as I had the car running with the defrost cranked up to help loosen the ice. If it is snowing - I just bush off the car, car NOT running - as it causes the snow to melt and stick the to car. If it is a mix of ice and snow - depends on how thick each layer is.
There really is no single RIGHT answer. The best you can do is minimize the amount of idling that the car is doing. Primarily, it is just a fuel wasting problem. Sure, there is the potential engine wear aspect, but modern engines have much better manufacturing tolerances and metallurgy - even with increased wear on the cam lobes - these engine will last a lot longer than what people want to hold onto them.
