Oil Change - Hot or Cold

Messages
104
Location
MO USA
Hello Everyone,

The "Short Changer Post" got me thinking about this subject. Do you change your oil when it is hot or cold?

I have always changed mine when the oil is hot and hopefully with all of the contaminants suspended in the oil that I am draining out of the engine. But, I have seen plenty of DIYers change it cold. Some cite the reasoning of getting burned, or just the convenience factor.

Inquiring minds want to know.
 
Messages
40,637
Location
Great Lakes
I change mine while it is still warm enough to flow easily through the extraction tube, but not too hot so that it doesn't soften the tube and cause it to collapse. That means I usually wait about 20-30 minutes or so after shutting off the engine.
 
Messages
666
Location
CA
Did mine yesterday. Cold. So MUCH BETTER. Didn’t burn my hands on hot oil or the filter and didn’t sear my arms while try to grease my driveline zerks while maneuvering around the exhaust. With the engine cool I can stick my head and hands all over to inspect things.

It didn’t take any longer than normal (a two beer operation).
 
Messages
35,631
Location
NY
Warm enough to safely handle. All I care about it getting the oil warm and the contaminants into suspension. I give the oil plenty of time to drain, so no worries there.
 
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Messages
5,183
Location
Ohio
Hello Everyone,

The "Short Changer Post" got me thinking about this subject. Do you change your oil when it is hot or cold?

I have always changed mine when the oil is hot and hopefully with all of the contaminants suspended in the oil that I am draining out of the engine. But, I have seen plenty of DIYers change it cold. Some cite the reasoning of getting burned, or just the convenience factor.

Inquiring minds want to know.
Been answered already 100+ times.

 
Messages
1,848
Location
Northeast Nebraska
I have to ask where do the contaminants go when the oil is cold? As the engine cools and the oil drains back to the pan do the contaminants get left behind. Just trying to wrap my head around this because I don't change my oil any longer so when I take it to the quick lube the oil is warm but when I leave it with my mech it's usually the night before so I know he's not letting it warm up so if this is an issue I might consider going back to the quick lube.
 
Messages
118
Location
UT
On my Lexus GX with 0W-20 I will be doing it cold next time. When I did it hot, it came out like a torrent that would put Niagara falls to shame. I am surprised I didn't get burnt to death under the car.
 
Messages
5,379
Location
down in the park
I have to ask where do the contaminants go when the oil is cold? As the engine cools and the oil drains back to the pan do the contaminants get left behind. Just trying to wrap my head around this because I don't change my oil any longer so when I take it to the quick lube the oil is warm but when I leave it with my mech it's usually the night before so I know he's not letting it warm up so if this is an issue I might consider going back to the quick lube.
the varnish you see in engine teardowns is the result of stuff that gets suspended when hot and deposited when cold.
 
Messages
4,287
Location
Central Wisconsin
usually do a change when oil is fairly hot. 10 minutes or so after shut down.
I have done them cold on rare occasions.
That old saw about "keeping contaminants in suspension" may be just that, an OLD SAW.
If changed on reasonable schedules, the additives in modern oils should keep those
contaminants in suspension in any case.

My 2¢
 
Messages
546
I do it when the oil is quite warm. I get good drainage and I don't come into contact with anything uncomfortably hot.
 
Messages
227
Location
eastern WA
Here's a related question. Does it really matter whether the oil is warm, assuming you let it drain long enough? Which of the following is preferable:

(1) change your oil on a 100 degree day after a week of sitting, without circulating the oil through the engine.
(2) change your oil on a zero degree day after a week of sitting, only starting the engine long enough to circulate the oil through the engine but not long enough to significantly warm the oil or engine.

Isn't the answer (2)? I thought the point was to pull the contaminants up from the bottom of the pan into suspension. (2) seems to achieve this goal, you just have to wait a little longer for the oil to completely drain. Does it really matter whether the oil actually warms up, assuming you let it drain long enough?
 
Messages
241
Location
North Carolina, USA
Depends. Normally once the engine has cooled down. However if the vehicle was sitting overnight in the dead of summer here in NC and the outside temp was above 80 degrees f, I'd NOT do a short drive to warm up the oil, however, during the winter when the outside temps are below say 50, I'd change it after being driven after a short cool down.
 
Messages
470
Location
Hedgesville, WV
I dont know if you call it warm or cold but whatever temp it gets to by my starting, backing out of the garage, setting up my ramps and pulling back in and up. Maybe 3 min run time. With 0 and 5w oil on a normal day it seemed like enough. You wont catch me changing my oil when its 20F out so I dont feel the need to get the engine hot.
 
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