Cold weather idling does increase fuel in oil!

[Drew99GT]

Granted, this is a diesel I think, but should apply to gas engines as well, particularly GDI.

Summary. They tested 3 cold starts and idled for 15 minutes, tested the oil, then started and drove 3 times for 15 minutes. Results? 50% more fuel from idling. Lake Speeds reasoning is ring gap. The faster you get the ring gap to spec at operating temp, the less fuel dilution you’ll get.

I still let it idle a couple minutes when it’s very cold though!

 

[DemoFly]

can't stand this bozo

 

[fantastic]

It's been long established that cold weather increases fuel use & consequently poses the risk of more fuel in oil as a result. Good to show the regular YT'er I suppose?

 

[Drew99GT]

Good ol Dave! I know, but the test was interesting!

Read the reviews for Dave’s Auto Center. Not good!

 

[Drew99GT]

It's been long established that cold weather increases fuel use & consequently poses the risk of more fuel in oil as a result. Good to show the regular YT'er I suppose?

For sure, but this test proves that idling to try and get heat in the engine and “warm it up” in cold weather is probably gonna increase engine wear as fuel dilution increases. Best practice is start, let it stabilize a few seconds, then light throttle and low load/rpms until engine temps get up. Then, SEND IT!

There’s a lady in my neighborhood that starts her Subaru and floors it up the street. Sounds like bbs in a tin can!

 

[rijndael]

Read the reviews for Dave’s Auto Center. Not good!

I read a number of the low rated reviews. This covers a lot of the ones I read:

• Upset because they wanted an estimate over the phone.
• They don't like the rates.
• They don't like paying for a diag.

 

[Drew99GT]

I read a number of the low rated reviews. This covers a lot of the ones I read:

• Upset because they wanted an estimate over the phone.
• They don't like the rates.
• They don't like paying for a diag.

That and selling a rebuild in an engine when a crate motor would be thousands less!

 

[FoxProTwisty]

Best practice is start, let it stabilize a few seconds, then light throttle and low load/rpms until engine temps get up. Then, SEND IT!

Turn block heater on before, then ^^^

 

[twX]

They tested 3 cold starts and idled for 15 minutes, tested the oil, then started and drove 3 times for 15 minutes. Results? 50% more fuel from idling.

This isn't really a good comparison. They should have compared a 15 minute trip with no idling, to a 15 minute trip with some idle time beforehand.

In the second case, the engine would have spent more time at higher temperatures, which would help boil the fuel away more quickly. It could be that fuel dilution would have actually been lower.

 

[Drew99GT]

This isn't really a good comparison. They should have compared a 15 minute trip with no idling, to a 15 minute trip with some idle time beforehand.

In the second case, the engine would have spent more time at higher temperatures, which would help boil the fuel away more quickly. It could be that fuel dilution would have actually been lower.

Lake Speed has indicated oil has to be at least 200 degrees for an extended period of time to boil off fuel, so I don’t think that any extended idling helps cause it just doesn’t put heat in an engine. Particularly the oil. On the test in the video, they got higher temps after 5 minutes of driving compared to 15 of idling.

Honestly, all this is just conjecture and entertaining. If you’re changing oil reasonably often and not hammering a cold engine, you’d never notice a difference in engine life most likely.

 

[Lubener]

I wish the ignorant younger folk on my street would realize this about idling. It seems when temps are below 40 degrees , just about everyone has to warm up their car for 10-15 minutes every morning.

 

[Hohn]

For sure, but this test proves that idling to try and get heat in the engine and “warm it up” in cold weather is probably gonna increase engine wear as fuel dilution increases. Best practice is start, let it stabilize a few seconds, then light throttle and low load/rpms until engine temps get up. Then, SEND IT!

There’s a lady in my neighborhood that starts her Subaru and floors it up the street. Sounds like bbs in a tin can!

Well, they it’s much worse with a diesel engine that with a gas engine.

A diesel engine has very low exhaust temperature at low load and takes forever to warm up.

Also, diesel engines need some intake velocity to properly swirl the fuel mix and get a quicker burn. At low load and low speed, intake air has low velocity, so the injected fuel burns slowly and incompletely.

A gasoline engine, by contrast, is idling against a closed throttle while consuming a much more volatile fuel. This means the fuel at idle vaporizes more readily. GDI still has some of the same “wait for air mixing” problems of diesel, but to a lesser degree. And PFI engines are essentially premixed with less wet-out.


So yes, every engine hates cold idling and nobody should do it. But diesels hate it MUCH more than gasoline engines do.

 

[Carlostrece]

I'm aware that excessive idling a cold engine puts more fuel into oil. Probably more soot too.

However, what about idling an engine when engine is at full op temp?

For example, in a drive up window line for fastfood, I let my engine idle with trans in Park while waiting. Then I pull into a parking spot and put it in Park and let it idle while I eat.

I do that so my battery gets charge more and discharged less on short trips. Also so I can enjoy some heat in winter.

How does idling 5-10 min in Neutral or Park when engine at (or near) full op temp affect oil and engine?

 

[rijndael]

How does idling 5-10 min in Neutral or Park with engine at (or near) full op temp affect oil and engine?

And, what if you have a car with cylinder deactivation running on 1/2 or 1/3rd of the regular cylinder vs a V8 without deactivation.

 

[fantastic]

For sure, but this test proves that idling to try and get heat in the engine and “warm it up” in cold weather is probably gonna increase engine wear as fuel dilution increases. Best practice is start, let it stabilize a few seconds, then light throttle and low load/rpms until engine temps get up. Then, SEND IT!

There’s a lady in my neighborhood that starts her Subaru and floors it up the street. Sounds like bbs in a tin can!

LOL Yeah, My F-350 Diesel will automatically idle up after around two minutes of idle time. I'd say no more than that before taking off but that may all depend on the ambient temperature on how long you can idle for. Sounds like the warmer it is the longer one could idle.

 

[Drew99GT]

I'm aware that excessive idling a cold engine puts more fuel into oil. Probably more soot too.

However, what about idling an engine when engine is at full op temp?

For example, in a drive up window line for fastfood, I let my engine idle with trans in Park while waiting. Then I pull into a parking spot and put it in Park and let it idle while I eat.

I do that so my battery gets charge more and discharged less on short trips. Also so I can enjoy some heat in winter.

How does idling 5-10 min in Neutral or Park when engine at (or near) full op temp affect oil and engine?

Since the engine is warm and the rings are closed up, I wound think idling an up to operating temp engine wouldn’t dilute fuel at all.

 

[Owen Lucas]

can't stand this bozo

Why? His videos are pretty good an informative. I'm no master tech but a lot of the stuff he says makes sense mechanically speaking. It appears that even dealers send their motors to him because no one really rebuilds motors anymore.

 

[rijndael]

I read a number of the low rated reviews. This covers a lot of the ones I read:

• Upset because they wanted an estimate over the phone.
• They don't like the rates.
• They don't like paying for a diag.

Ford Boss Me, on YouTube, just posted a video on his nickname "Dirtbag Dave".

 

[FCD]

I'm from Finland, i got my license there, my teacher always told me unless it's extremely cold, start the engine, let it run for a minute or so, clear snow and ice if needed , then take off and drive gently until the engine begins to warm up , keep the revs low, change gears gently.

Putting a light load on the engine and drivetrain makes it warm up much faster than idling, no question.

Sure nowadays most people have block heaters that you can even order pre fitted to a new car, most people park outside you have your spot and there is a post where you plug it in and that's it.

 

[FCD]

I'm aware that excessive idling a cold engine puts more fuel into oil. Probably more soot too.

However, what about idling an engine when engine is at full op temp?

For example, in a drive up window line for fastfood, I let my engine idle with trans in Park while waiting. Then I pull into a parking spot and put it in Park and let it idle while I eat.

I do that so my battery gets charge more and discharged less on short trips. Also so I can enjoy some heat in winter.

How does idling 5-10 min in Neutral or Park when engine at (or near) full op temp affect oil and engine?

5-10min hot is nothing.