Why You Should Never Warm Up Your Car

[MobilOne]

So what is our take on the pontification that started this thread. NEVER warm up? Or SOMETIMES warm up if the occasion warrants it?

[niky]

Originally Posted by me and my metro

Some modern "clean" Diesels inject fuel on the exhaust stroke to heat the cat to burn the soot in the exhaust filter. This regen process works fine if you happen to be driving on the highway. I work for an electric utility and this system has caused a lot of problems when the regen process gets interrupted. Our trucks often run at low speeds and run a power take off to power the boom. The regen process only runs while driving. Unburned fuel ends up in the crankcase diluting the oil. That and all the high pressure fuel system is under the valve covers, if something leaks it stays inside. The oil capacity is 15 quarts and we have to monitor oil level for over level. We have drained as much as 25 quarts of diluted oil from these trucks.

I'd heard Cummins (or Caterpillar?) injects the extra fuel post-cylinder, straight into the exhaust. I still don't understand why other makers don't do this. Doesn't even have to be one of those fancy high-pressure piezo injectors... could be done with a regular old-tech injector.

[nemo]

Originally Posted by MobilOne

So what is our take on the pontification that started this thread. NEVER warm up? Or SOMETIMES warm up if the occasion warrants it?

It not a question of warming up or not. The question is if warming up by idling the engine is efficient and does it reduce or prolong the longevity of the engine.

[Frank Lee]

Canadian government is one hella lot more proactive about advising against idling than any entity I've found in the U.S.. Once when researching idling online I found several Canadian sites that advised against it and backed it up with research findings.

The Owner's Manuals I've looked in recommend to drive straight away.

I do that the vast majority of the time. I believe in the faster warm-up while driving gently theory. I'll putz down the street at barely above idle speed, then still go slow in top gear until the temp gauge moves (which happens pretty quickly- FAR quicker than the time most people around here idle via remote start).

If it's -30F I'll let it idle while I'm scraping the windows, and that's about the only idling time my engines ever see.

[LittleBlackDuck]

Originally Posted by Frank Lee

The Owner's Manuals I've looked in recommend to drive straight away.

I do that the vast majority of the time. I believe in the faster warm-up while driving gently theory. I'll putz down the street at barely above idle speed, then still go slow in top gear until the temp gauge moves (which happens pretty quickly- FAR quicker than the time most people around here idle via remote start).

If it's -30F I'll let it idle while I'm scraping the windows, and that's about the only idling time my engines ever see.

Agree totally. The only reason to idle for warmup is if the vehicle is iced / frosted up and it is unsafe to drive it. If it is really freezing a brief idle (1-2 mins max) helps to get a bit of chill off before loading the engine up.

Simon

[Erasmo]

I've always wondered why electric block heaters aren't more popular in the States, in the Northern part of Europe the are really common.

[oil pan 4]

Originally Posted by Erasmo

I've always wondered why electric block heaters aren't more popular in the States, in the Northern part of Europe the are really common.

Ignorance and laziness.

[gumby79]

Originally Posted by Erasmo

I've always wondered why electric block heaters aren't more popular in the States, in the Northern part of Europe the are really common.

In the northern parts of the USA plug-in heating is common. Some stores have plugs in the parking lots so people don't idle wile in the store shopping . Were plugs are scarce like ranches some just don't turn it off till spring ,for if they do they have to tarp the truck start a fire under the oil pan and hope it starts.
Northern US is like northern EU . Southwest US is like the Middle East temperature wise. I've had my temp gage read 117°f before starting cold in summer in Vegas . Was in Las Vegas last week @102°f now home grass is frosty by 7:30pm. And first dusting of snow@5500'. Also most people under 35 have never experienced a cold-blooded carburetor were fuel wash down was a major problem. So for most idling till it is drivable is unnessasary.

[Mewtwo]

With a carburetor, it was essential to let the car idle for minutes before driving it in order to make sure the engine would run properly. But with modern cars, it's not the engine itself that needs to be warmed up when it's cold outside. Experts are torn on this issue.

[Erasmo]

All my cars still have carbs but the effect is most noticeable on my XJ600 which suffers from carb icing when you go on the motorway before warming up.