Was I WRONG about COLD Idling?

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In today’s episode, we’re heading back to the chalkboard for a deep dive experiment testing cold idle starts vs. cold driving to heat up engine oil. To get the most accurate results, we logged each date, time, and temperature during testing for a detailed analysis!

But we didn’t stop there! We brought in special guest Lake Speed Jr. to test our oil samples and break down the science behind engine wear. Which method is actually worse for your engine? The results may surprise you!

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#ColdStartTest #EngineWear #OilAnalysis #MechanicScience #ShopExperiments

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@themotoroilgeek

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[themotoroilgeek]

Thanks for letting me help out! This is also why hybrids have higher fuel dilution and moisture in the oil issues, especially in cold weather. For those wondering about driving after idling and boiling off the fuel dilution, the oil temperature must exceed 200F to boil off 50% of the Gasoline. Diesel has a much higher distillation temperature, so even driving the truck for 10 minutes would not get the oil hot enough to boil off the diesel.

[tylerfb]

The Society of Automotive Engineers figured out how engines wear many decades ago. The piston rings and the cylinders are the key wear area, because that's why you end up replacing engines. Piston ring/cylinder wear happens most when the engine coolant is below 160 degrees F. It is pretty much negligible above that. The other contributor is engine LOAD not RPM. High LOAD and low TEMP lead to high cylinder/piston ring wear. The remedy: get heat into the engine as quickly as possible before you load it.

THAT's why the recommended procedure is to start and idle for maybe a minute to get oil throughout and pressures up, then drive gently (light loading) until the coolant temp is normal. That is the best compromise between heat and use. If you cannot drive gently, you should idle longer and high idle. But what you should really do is get a block heater. That will allow you to drive under high load immediately.

[alanpillow]

Wow! Thank you for the info. I am driving my Dad's 2003 F-350 Power Stroke V8 which I inherited after he passed away, and I know nothing about it. Your videos are a value to me. Thank you all!
He had the "bullet proof" service dont to it.

[errbodyknowsdarules]

Allow me to summarize ~25 mins. Start your cold vehicle, drive it with a soft foot until it comes up to temp.

[seedycanuck]

I drove the Ice Road from Yellowknife to Ekati mine for 8 years. Start truck, leave Whitehorse, YT drive to Hay River NT. Load Super B with diesel, drive to Yellowknife, then up the Ice to the mine. Truck was only ever shut down when it was time to change oil - every 250 hours. Running 5W30 full Syn. When parked, Cat engines were left at high idle - about 900 RPM. This lasted for 8 or 9 weeks until Ice started to melt and we returned to Whitehorse, Newer trucks with all the sensors, EGR, DEF etc were broke down all the time. My truck had 2 pieces of electronics - the VHF radio and the stereo.

[kevinyancey]

What you're missing is idling cold, then drive it. People don't start their vehicles and let them idle for 10 minutes, then shut them down. Oil temps will climb to around 215 or so degrees under normal driving, higher if you're towing or driving it hard. That gives the oil the heat it needs to flash off light oil vapors and boil out moisture. The problem with starting up cold and driving it has more to do with windshields fogging or icing up from your body heat and breath. I've started vehicles in -40 and they were unable to move until they got heat into them. Trans fluid don't much like extreme cold, just like engine oil. Funny story, one winter morning, I couldn't get my two gas cars started, but my diesel started without assistance! It created a huge cloud until it got warm, and it was one cylinder at a time coming online as I cranked it over.

[wingman]

I remember the old VW beetle manual. It said “let the car warm up as long as it takes to roll a cigarette”

[DrKnowsMore]

The other problem with this analysis is that most of us don't idle our car for 10 minutes and then shut it off and let it sit. We usually idle for 5 minutes or 10 minutes and then drive. I'd like to see what kind of impact that has.

[JVinAK]

I live in Alaska and drive a diesel. Even with heaters the engine still gets really cold. Im less concerned about fuel in the oil and more concerned about breaking stuff with the temperatures we experience up here. Powersteering and brakes just simply don't work immediately after starting at -40F. The powersteering fluid and brake fluid at that temperature is thicker than molasses!
If it's colder than -50F I don't drive to avoid breaking stuff/blowing hoses.
If it's colder than 0F I let it warm up until the high idle shuts off.
If it's above 0F I let it warm up for a few minutes.
If it's the temperatures shown in the video, I do exactly what's in the video.

[bushwriter]

Another consideration here is to change your oil as soon as things warm up. In the winter we are going to find our vehicles iced over and needing to thaw out before you can move, which makes idling necessary. Don't wait for the mileage. Just change it when things warm up.

[cj]

My 04 dodge has 800, 000 miles on it and so far have never touched the engine. I change oil every 10, 000 miles and also only use Mobil delvac 1300. I have only 2 or 3 times ever had to add a quart of oil between oil changes. This truck pulls campers for a living. 2 to 3 times a week it idles cold for 10-20 minutes. When I’m pulling a trailer this truck never shuts off until I’m home. My point is, if cold idling was so detrimental to the engine I should be rebuilding mine every year. I understand people think these gentlemen are the elites to listen too but I would challenge their real world knowledge of people who work these diesels everyday and not just own them for picking up groceries. I spent 30 years working for a commercial farming business. I ran a lot of different equipment. We idled everything when it was cold. I can honestly say in those 30 years we never had any engine failures or any engines with excessive oil consumption. I’m sure their tests are accurate and I’m not debating that there is more fuel dilution idling cold, I’m sure there is but is it enough to worry about? In my case apparently not but if your sole purpose of owning a diesel pickup is just to drive to work and back and not for doing work then I would probably agree you should plug your trucks in when below 50 and start and go but as for the person that actually works the truck everyday all day I don’t think it matters.

[dennisgardiner]

Fuel dilution and moisture accumulation is a problem in cold weather. In cold climates, I found the engines ran better if the oil got fully up to temperature. This both evaporates moisture from the oil, and with gasoline engine evaporating fuel vapors, drawn through the PCV system. When I studied in Tulsa during winters my school was less than 10 minutes away. The engine coolant barely got warm in that time. The oil 100% never got to 180° for over a month. So bad that the oil cap started showing milkshake moisture.
After driving to 2 hours (round trip) the weekend, I noticed two things. 1) The engine began to run better. 2) The moisture indication on the oil cap was gone.
Engines need to get up to temperature to run properly in the long run.

[Ozgrade]

It's Saturday afternoon, on a hot summers day here in Australia. The lawns are done, chores are all done. The afternoon is all mine. I couldn't think of a better way to spend it than watching two highly knowledgeable guys talking about oil temperature.

[matthewmcdaniel]

Great video! I am a firm believer in starting My car, plug phone in, put seatbelt on, then going once my idle rpms drop at least once. Then gently drive like normal, you'll save a ton of gas too, and I get 44 combined lifetime over 22k miles. Car runs like a top, no gas smell when I change the oil, and I live in Michigan. 2024 Honda Civic 2.0 NA engine. 5k oil changes

[digger]

You've got some other things to consider. At -0° temperatures, transmissions, power steering and hydraulics can be so cold, they won't steer or shift or operate until the oil has been circulated through the radiator cooler/ (warmer in that case). I've had to run some diesel powered equipment for over an 1 hr before things could start to operate. Hydraulic equipment like excavators and especially Cranes, hate below zero temps . If you rev it up, or tried to operate them, you could blow filter gaskets or cavitate the pumps and create a real mess that might put you down for 1/2 a day at best or for weeks at the worst. Idling for hours may not be good for the engine, but the rest of what it's hooked to, makes it necessary. Oh and let's not forget, a lot of diesels have air brake systems. You have to idle till you have full air pressure, and when it's cold, it can take waaay looonger than your 5-10 minutes.

[myvideosrockthehouse]

In europe they had a webasto option on many diesels. It's a small and efficient diesel heater that warms up the coolant. Once the coolant is warm, the electrical coolant pump activated with the heater fan.

When you get in and start, the motor is warm and so is the interior. The diesel webasto is superior as it can yield more heat then electric heaters which are limited in current.

Once we start valuing long term usability in our environmental equations, the polluting webasti option will make a lot of sense.

[russsalvage]

Worked on fleet of log trucks 50 years ago.
Cummins engineers gave same advice then.
Start the engine, let it idle a minute so the gears in engine snd transmission had a good film and roll out easy.

[Neukom]

So plugging in your block heater / coolant heater is the best possible thing you can do for your engine....because you don't don't have to idle it and all the parts like piston rings etc are warm plus better fuel atomization, also not only that it's going to get to full temp much more quickly and lubrication will be better at start and getting oil up to temp quicker. Bonus with my TDI and my coolant heater, when I start the engine, and turn my heat on, it's nice and toasty from the moment I start it. If you care about your diesel, plug it in plug it in lol like the commercial haha

[shakezula]

I live in northern Minnesota where low temps are well below zero for much of the winter, and I can tell you that there's a big difference between 28 degrees and 28 degrees below zero. I agree that it's just fine to start driving immediately when the temps are just below freezing, but when you get well below zero it's quite apparent that the car does NOT like being asked to move. Maybe you'll get more fuel in the oil, but based on how the vehicle drives I can say that it appreciates being given 10 minutes to warm a little before actually moving.

I'd be curious to see the results of this experiment when temps are 40-50 degrees colder (both fuel content and wear metals).

[TreatsOnTheStreets]

We idle our diesel for at least 10 minutes every morning in winter. I also do oil analysis on every oil change. I have never had excessive fuel in the oil. Usually it is less than the average. As long as you're driving it to the point that the oil heats up it isn't going to be a problem. Change your oil frequently either way and you'll be fine. As for the DPF, can't speak to that. Isn't that what regen is for?