Draining oil hot or cold questions?

[ZZman]

1. Do you normally drain your oil hot, warm or cold? 2. If oil thins when cold and thickens when hot, why does hot oil drain quicker? * I drain my oil hot.

 

[Bottom_Feeder]

3. I drain it warm.

 

[knerml]

You should drain oil right after turning off a warmed up engine, because: 1. Contaminates are still in suspension, and have not had time to settle into the pan or separate out 2. Less initial start-up wear, after the change Cold oil may drain faster because it is all in the pan. Warm oil needs to drain down off the top of the engine and galleries.

 

[JohnnyJohnson]

Originally Posted By: Bottom_Feeder

3. I drain it warm.

 

[gathermewool]

Originally Posted By: ZZman

If oil thins when cold and thickens when hot, why does hot oil drain quicker?

Oil thickens when cold, just like the vast majority of other liquids. It drains better when hot, because it's thinner. Having driven the vehicle recently also mixes the oil, so if anything had settled out, it will likely be picked up and carried out the drain hole with the rest of the oil.

 

[Quattro Pete]

Originally Posted By: ZZman

1. Do you normally drain your oil hot, warm or cold?

I extract it when warm/hot.

Quote:

2. If oil thins when cold and thickens when hot, why does hot oil drain quicker?

Oil does not thin when cold. Oil thickens when cold.

 

[53' Stude]

Yep, I extract my oil when it’s warm after a nice drive. Oil extractor is way to go

 

[Ethan1]

Originally Posted By: ZZman

2. If oil thins when cold and thickens when hot, why does hot oil drain quicker?

Lol is that a trick question?

 

[eljefino]

Originally Posted By: ZZman

2. If oil thins when cold and thickens when hot, why does hot oil drain quicker?

A multigrade oil fights its normal tendency to thin when hot, but isn't completely successful, and still thins out.

 

[BAJA_05]

When hot with oil/particulates in suspension.

 

[3800Series]

What ever it is at the time. If I've been driving it recently it will be warm/hot if not cold. I'm not going to go out of my way to drain a slightly warmer oil. Vehicle hasn't imploded yet.

 

[Chris142]

Depends on the circumstances. If I get to work early I will drain it hot. If the truck is due and I dont have time I will do it cold in the parking lot before I go home.

 

[Alex_V]

Preferably within 10 minutes of shut-down. I'll drain one cold rather than luke-warm. The longer it can drain the better.

 

[Linctex]

Originally Posted By: knerml

You should drain oil right after turning off a warmed up engine, because: 1. Contaminates are still in suspension, and have not had time to settle into the pan or separate out

This actually takes a long time to happen. I drain mine after a highway trip, and about 30-40 minutes cool down. I don't wait for it to stop dripping - plug in, new oil in, and running again before it ever cools down completely.

 

[4WD]

Position ramps, start motor, drive on ramps, turn off. Gather wrenches, funnel, oil, shop towels, hand cleaner … Position oil filter/oil for photo and snap odometer pic too … Now at scientifically proven drain temp ~ go for it …

 

[eyeofthetiger]

I drain my oil cold. It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.

 

[4WD]

Originally Posted By: eyeofthetiger

I drain my oil cold. It has nothing to do with suspending contaminants or reducing startup wear. I just prefer working on cold engines.

And nothing wrong with putting HSE first … this is likely a subject that brings folks to micrometer a brick …

 

[Leo99]

Usually a cold engine. Usually on a Sunday morning and the car's been sitting all night. I'm not going to drive it around to warm up the engine. If the engine is already warm, I'll change the oil while it's warm and won't wait for it to cool down. I don't think it makes any difference what temperature the oil is when it's changed.

 

[Mr Nice]

Originally Posted By: Leo99

Usually a cold engine. Usually on a Sunday morning and the car's been sitting all night. I'm not going to drive it around to warm up the engine. If the engine is already warm, I'll change the oil while it's warm and won't wait for it to cool down. I don't think it makes any difference what temperature the oil is when it's changed.

I agree. I try to do it when warm, if not draining it cold won't hurt.

 

[Nick1994]

Oil thickens when cold and thins when hot, not the other way around. Think of it like bacon grease in a pan. If you leave it overnight, it turns solid (thick). If you put that skillet back on a hot burner it would turn liquid again (thin).