Warm-Up Discussion

[voon]

Edit by admin: This discussion was moved from within another...

Do you really use those apps? I can't think of any situation where I'd really need any of that kind of functionality. I personally have no reason to remote start my car (since this is a) forbidden here due to crappy exhaust gases in a cold engine and b) because low cold revs hurt the engine and won't heat it up fast enough). The only use I could see is GPC lcoating your stolen car (but for that it would need a SIMcarded GPS unit onboard).

 

[Clearly Canadian]

crappy exhaust gases in a cold engine and b) because low cold revs hurt the engine and won't heat it up fast enough)

Please explain?

 

[voon]

A Low revving engine at 600 rpm or so in standing position isn't heating up the engine block and oil fast enough to compensate the microdamage done by a badly oiled piston. Hence accumulating minidamage over time. Second, the cold engine at those RPM isn't combusting the fuel properly, resulting in a worse output at the exhaust. The latter is the reason that running the engine like this is forbidden by law around here. It also can damage the catalysators. ALso, in the cold phase of the engine, condense fuel mixture is putting on a film along the walls, which ends up in the oil, further thinning out the oil. Doing this extensively is risking an early piston jam.

Partially explained in pages like Warming Up Your Car in the Cold Just Harms the Engine and others.

This might not apply much in a climate, that's never cold.

 

[Bamm1]

A Low revving engine at 600 rpm or so in standing position isn't heating up the engine block and oil fast enough to compensate the microdamage done by a badly oiled piston. Hence accumulating minidamage over time. Second, the cold engine at those RPM isn't combusting the fuel properly, resulting in a worse output at the exhaust. The latter is the reason that running the engine like this is forbidden by law around here. It also can damage the catalysators. ALso, in the cold phase of the engine, condense fuel mixture is putting on a film along the walls, which ends up in the oil, further thinning out the oil. Doing this extensively is risking an early piston jam.

Partially explained in pages like Warming Up Your Car in the Cold Just Harms the Engine and others.

This might not apply much in a climate, that's never cold.

Most cars have an idle much higher than 600 rpm when the temp is in the "cold" range. So the speed at which the engine approaches operating temp can vary.

Also:
https://jalopnik.com/exactly-why-you-need-to-warm-up-your-car-when-its-cold-1821737173

 

[voon]

Preheat (also stated by that ralley school guy) is only a good idea, if you immediatly have to put your car under huge load ... i.e. if you're on a highway after 50 meters off your house or diretly steep up a moutnain pass or something similar. In all other occasions, where as a commuter you can slowly accelerate and just gently drive for the first kilometer, should be safer for your engine. Idle revving is warming the engine very very slowly, keeping the pistons under a worse average time of badly oiled etc than immediatly, but gently drive off, warming up the engine much quicker and bringing everything into operating ideals much faster, reducing the average damage done compared to idling it for a few minutes.

Those two lines cross somewhere .. can't exactly say where, so your mileage may vary, but I never idle it in the cold (but I also don't have to do huge loads on my car when driving to work).

 

[Bamm1]

Preheat (also stated by that ralley school guy) is only a good idea, if you immediatly have to put your car under huge load ... i.e. if you're on a highway after 50 meters off your house or diretly steep up a moutnain pass or something similar. In all other occasions, where as a commuter you can slowly accelerate and just gently drive for the first kilometer, should be safer for your engine. Idle revving is warming the engine very very slowly, keeping the pistons under a worse average time of badly oiled etc than immediatly, but gently drive off, warming up the engine much quicker and bringing everything into operating ideals much faster, reducing the average damage done compared to idling it for a few minutes.

Those two lines cross somewhere .. can't exactly say where, so your mileage may vary, but I never idle it in the cold (but I also don't have to do huge loads on my car when driving to work).

My concern is someone with a 5 month old is going to read your post and think idling after a cold start is going to cause their engine to seize. So they are going jam their "can't even drink cold liquids" infant in their -17 C car and drive off.

Idling at 1000 rpm for 6 min. and then driving to their destination at 2000 rpm is not going to be much different in terms of engine wear than just driving at 2000 rpm.

Keep in mind that some trips may be so short you never get to proper operating temp. So remote starting while you get ready to leave is actually beneficial.

I suspect most of the "you will break your car" talk around idling when cold is a scare tactic to combat climate change vs. actually causing engine failure.

 

[xot1]

In before the thread split.

 

[mldavis2]

I agree with @voon here and should add that there is much more to warm up than just engine oil. Transmission oil, wheel bearings, differential fluid, transfer case (if AWD), etc. Gentle driving is much better than long idling because the engine warms up faster under light loads and everything else with it. JMHO.

 

[voon]

@Bamm1
Maybe, who knows Also, idling in cold will not instantly break your engine. I suspect it will just shorten its life by introducing early microdamage, that slowly leads to a critical failure years later. People, that buy a new car and sell it 3 years later will probably never see a serious issue while letting idle at cold mornings.

Also not trying to tell anyone what to do ... if soemthing works for them, sure. I just prefer the gentle drive method, since I believe that background.

 

[Bamm1]

@Bamm1
Maybe, who knows Also, idling in cold will not instantly break your engine. I suspect it will just shorten its life by introducing early microdamage, that slowly leads to a critical failure years later. People, that buy a new car and sell it 3 years later will probably never see a serious issue while letting idle at cold mornings.

Also not trying to tell anyone what to do ... if soemthing works for them, sure. I just prefer the gentle drive method, since I believe that background.

But how many years later? I am not sure I have ever heard of a failure directly attributed to cold idling. The only people I know who seized an engine did so after extensive modifications. In the US the average person keeps a new car for 6 years. If it happens well after that I am not sure I should be concerned. Also, if I buy a used car who the heck knows if the previous owner idled the h*ll out of it But those are not failing left and right either.

There was a time when some might say I was obsessed with engine oil testing. I submitted engine oil, diff oil, you name the lubricate and I probably tried to test it. The vehicle in question experienced long periods of extended cold idling due to reasons no one cares to hear. At no point did any of the reports show anything beyond normal wear and tear. No excessive fuel dilution, etc. It just showed the oil I had chosen worked very well. Same goes for the diff, trans, etc. Even if the damage is not visible to the naked eye said "damage" to the piston, rings, etc. will cause metal to slough off into the oil. I believe one of the reasons I did not see anything is that modern synthetic oils can still flow at much lower temperatures compared to the old conventional oils. Most of the damage would occur right at startup but then be mitigated once the oil started flowing shortly thereafter.

I do believe excessive cold idling should be avoided. Wastes gas, etc. But using the remote start to get a jump on the coolant reaching normal operating temp is perfectly fine (however long your duration of ownership is). Then you just transition to a low load drive to get the oil up to the normal operating temp. If I can have use my phone or Alexa to start the process for me, all the better.

 

[voon]

How many years .. Good question, hard to anwer, as with any tiny, creeping microdamage situations .. that's why it would be close to impossible to prove anything comparing what we did, with all those different cars, environments etc. I guess the only conclusive thing would be a laboratory test. It actually really wonder about that.