Oil changes - when is best? Hot or cold engine?

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Tue 1 Jan 2008 14:31
Oil changes - when is best? Hot or cold engine? - Doc
I have always, as per book, changed my engine oil hot.
Is there any benefit in changing hot rather than cold, apart from when hot the oil flows quicker?

Edited by Dynamic Dave on 01/01/2008 at 16:18

Reply | Report as offensive | Link
Tue 1 Jan 2008 17:09
Oil changes - when is best? Hot or cold engine? - Ruperts Trooper
If you're not in a hurry, change it cold but allow plenty of time for the "thick" oil to drain out of the sump - all the impurities will be in the sump if it's stood overnight so I've never seen the point of warming oil up, moving the impurities into the oil galleries.
Reply | Report as offensive | Link
Tue 1 Jan 2008 17:35
Oil changes - when is best? Hot or cold engine? - yorkiebar
warm, but not hot, is probably best time to chage imo.

Oil will flow better than cold and will contain any impurities with it better. Still best to have a cup of tea while its draining to alow all the old crud out. The last dregs to come out are the most important ones to get out of course!

Reply | Report as offensive | Link
Tue 1 Jan 2008 19:47
Oil changes - when is best? Hot or cold engine? - storme
ive just done mine cold..but i left it to drain ALL night.
then in the morning, i replaced everything and re-filled the oil and off i went :)
.
Reply | Report as offensive | Link
Tue 1 Jan 2008 20:00
Oil changes - when is best? Hot or cold engine? - Number_Cruncher
Hot or cold?

Not something to lose much sleep over in my opinion. You always have the oil galleries full of oil that can't be changed, on many cars, an oil cooler too.

Fretting about getting the last drop of oil out is akin to an equivalent reduction in the oil change interval of a few hundred miles - since we in the backroom change our oil every second Wednesday anyway, it's not much of an issue.

Number_Cruncher
Reply | Report as offensive | Link
Wed 2 Jan 2008 13:27
Oil changes - when is best? Hot or cold engine? - OldSock
In addition, it's easy to under-estimate how hot 'hot' oil can feel on bare skin.....!
Reply | Report as offensive | Link
Wed 2 Jan 2008 13:37
Oil changes - when is best? Hot or cold engine? - Ruperts Trooper
80 degree oil burns/scalds skin !!
Reply | Report as offensive | Link
Wed 2 Jan 2008 13:41
Oil changes - when is best? Hot or cold engine? - Screwloose

Which is why techs wear rubber gloves.
Reply | Report as offensive | Link
Wed 2 Jan 2008 13:54
Oil changes - when is best? Hot or cold engine? - drivewell
and techs also (should) know that used oil is carcinogenic. Sure, if you wash it off quickly your risk is negligible, but better to have no unnecessary contact at all.
Reply | Report as offensive | Link
Wed 2 Jan 2008 14:05
Oil changes - when is best? Hot or cold engine? - OldSock
Which is why techs wear rubber gloves.


Some sensitivity of touch is lost through rubber, making the handling of delicate items trickier than it need be......
Reply | Report as offensive | Link
Wed 2 Jan 2008 15:11
Oil changes - when is best? Hot or cold engine? - drivewell
"Some sensitivity of touch is lost through rubber making the handling of delicate items trickier than it need be...... "

I have a friend who is an eye surgeon - he wears gloves (all be it fine latex), and he doesn't seem to worry about the sensitivity (although granted, much of their work now involves micromanipulators).

I use pvc gloves when working on my car or my wife's (mainly because professionally, folks would not want to see me with ingrained dirt on my fingers). I have never had a situation where lack of sensitivity of touch was a problem while working on a car.
Reply | Report as offensive | Link