Changing your oil when it's hot - good/bad/who cares?

[OS4A]

Fumoto valve...hot/cold insignificant. Easy to open and stay out of the way as it were.

 

[Astro14]

Every few months, someone joins, and asks the same question.

And the same points are made.

Over, and over, and over, and over…

I really wish that the first thing new members would learn is how to use search. It works really well.

R

Thread 'changing oil in cold engine'

Oct 9, 2025

I've always heard that an engine should be warm before the oil is changed. This seems counter intuitive. During the cooling process the oil has been able to completely drain into the pan. So why warm it up and let the oil settle again? BTW I use 5w20 despite what the manual reflects (0w20). I live in a warm climate.

• RetiredSux
• Replies: 117
• Forum: Mechanical/Maintenance Forum

• 

 

[Mainia]

Warm 70% / Hot 29% / Cold 1%.

 

[JeffKeryk]

The MityVac likes hot oil extractions. The plug drain (aka me) likes not-too-hot or even cold. Sometimes something else is hot down there tool.

Bottom line? Just change it.

 

[OM617YOTA]

The benefit of changing the oil at all utterly eclipses any difference between a hot vs. cold change.

Change the oil however is convenient. Hot vs. cold isn't something I'm willing to care about.

 

[oil pan 4]

Hotter oil drains faster. Faster is better.

 

[gfh77665]

I am more concerned getting burned on the hot concrete of my driveway than with the oil. I have to lay a carpet down to avoid getting scorched. I just use a small rag to remove the drain plug and filter. It catches the dribble too.

 

[nealberke]

I like my oil drains like I like my relationships… cold and short.

And draining.

 

[JunkdrawerDog]

I will warm the engine slightly to speed things up but never hot. Who wants the discomfort or possibility of a nasty burn.

 

[jadmt]

been changing my own oil since the 70's always hot and never had an issue burning myself..

 

[Tricknologist]

Every few months, someone joins, and asks the same question.

And the same points are made.

Over, and over, and over, and over…

I really wish that the first thing new members would learn is how to use search. It works really well.

R

Thread 'changing oil in cold engine'

Oct 9, 2025

I've always heard that an engine should be warm before the oil is changed. This seems counter intuitive. During the cooling process the oil has been able to completely drain into the pan. So why warm it up and let the oil settle again? BTW I use 5w20 despite what the manual reflects (0w20). I live in a warm climate.

• RetiredSux
• Replies: 117
• Forum: Mechanical/Maintenance Forum

• 

To be fair, Xenforo search is notoriously crap

 

[iCurious]

Ideally hot for obvious reasons. But there are times I do it cold.

 

[chazthespaz]

I vote for changing the oil warm; if engine is hot I let it cool down a bit, or if cold I start it up and get the tempreature up off the cold stop.

 

[kschachn]

To be fair, Xenforo search is notoriously crap

That's not the best way to search for these very common questions.

 

[Hootbro]

90% of any decision for me to change it hot or cold boiled down to how the drain plug removal was and if the stream could drain into a container with minimal interference of getting on me and/or the vehicle. Same with considering the oil filter removal. Oil drain valves solve most of that problem .

 

[Sam_Julier]

I drain the oil when it’s hot. 160 degrees+

The ValvoMax drain on the S60, MityVac suction for the 300D, magnetic flexible bolt socket for the 240s and thick rubber gloves makes the job easy.

I always let the oil drain until the engine compartment and oil filter is cool. I’ll cut the grass or run errands while the filter cools and the oil drains.

No sense in rushing. I’m not on the clock.

 

[Braapdaddy]

On a 2.7 GM with the silly plastic 3/8 square its best to drain when cold to avoid the absolute mess it makes when hot

The guy designing the drain plug location never has to drain one or they would simply move it to the rear of vehicle a few inches and reduce the diameter of the hole

 

[Jeep_Riot]

I'm not arguing but I am trying to figure out your rationale here. I drove my car yesterday and the oil was at operating temperature. Overnight the oil and the suspended impurities have drained as much as they are going to into the pan.

In the morning, I can start the engine, pump all those impurities that were conveniently sitting in the pan up into the engine and hope they all drain back down again into the pan before I'm done or I can just drain the cold oil with all the impurities in the oil pan.

I understand oil that is warm/hot flows better but are there really any issues with oil flow when the oil sits overnight? I guess in my mind you've already concentrated all the impurities to where you need them to remove them so why mix them all up again?

Pour in a quart of oil when the pan is empty for good measure.

Oh laud, did I just say that?

 

[4wd]

On a 2.7 GM with the silly plastic 3/8 square its best to drain when cold to avoid the absolute mess it makes when hot

The guy designing the drain plug location never has to drain one or they would simply move it to the rear of vehicle a few inches and reduce the diameter of the hole

Seems odd - on the 5.3L the plug location is perfect - no pans for it or filter - and even my Fumoto is well protected …

 

[4wd]

Pour in a quart of oil when the pan is empty for good measure.

Oh laud, did I just say that?

Well, these I have posted before are after what he described - sat over night - and since I was not changing the filter - did not start it to go on ramps … (can reach Fumoto) …
The clean/cold oil went from poured to drained in seconds - barely picked up anything (middle sample) sweeping the oil pan …