Change oil Hot or Cold?

Bryanccfshr · Dec 30, 2006

I just did a hot honey vs- room temp honey drain experiment... Each cup recived a equal size hole. Each recieved 1 tbsp of honey. The results are obvious.
I don't feel like explaining motor oil or PAO gearbox lubricant in the office so this will have to do for now.
First the room rtemp High viscosity fluid

Now the higher temp lower viscosity fluid

Not even close...the hot honey was on the right after 5 minutes.

Notice how the higher viscosity cooler fluid sticks to the side of the cup and has more surface tension resisting pour and flow towards the exit hole.

tenderloin · Dec 30, 2006

Honey? That's close to a 20 or 30 oil......

The drain on your vehicle is that small?

You are a smart guy...you can do better than that

BTW Do you heat the bottles of new oil before you attempt to pour them into your engine?

After you pour 'cold" oil into your engine, how much oil is still left in the bottle? How long before the bottle is virtually empty?

Case closed

dekylereese · Dec 30, 2006

anyone want to write mythbusters about this?

LAGA · Dec 30, 2006

I change mine when it`s neither hot or cold, but when it`s warm

Bryanccfshr · Dec 30, 2006

I tried it with some food grade PAO I had sitting around(later last night) but it did not photograph as well. Yes the holes were purposely small because the volume was small. If I can get some dye I will try the PAO again.

Flat_H · Dec 30, 2006

I change my oil hot and it's no problem because I have the fumoto valve.

My oil changes takes about 45 minutes from start to finish.

cos · Dec 30, 2006

Hot or cold, whichever is convenient.

427Z06 · Dec 31, 2006

Quote:

BTW Do you heat the bottles of new oil before you attempt to pour them into your engine?

After you pour 'cold" oil into your engine, how much oil is still left in the bottle? How long before the bottle is virtually empty?

The oil you're pouring from your bottle doesn't have to travel through bearing clearances and pin-hole sized oil passages on the way to the oil pan.

WishIhadatruck · Dec 31, 2006

I always drain it warm. I park it on the ramps when I get home or after letting the car warm up and then drain it as soon as it cools off enough it won't burn me. I don't really worry about it too much. I mostly notice my drain pan pours out cleaner and faster when the oil is warm. If it is cold it goes through the funnel and into the jug slower which is probably my biggest concern. I doubt that the engine cares at all. Does it care if you get out 98% of the old oil or 99%? Over in the transmission oil section 1/2 the people are perfectly ok getting out 4qts out of 10 and just doing it more often but over here when it is the engine oil everyone cares to get out the most but can't agree on how. I say it isn't worth the worry. Alternate between cold and hot drains over the life of a car and see if you can tell the difference between the UOA's on each and every one. Good luck.

ARB1977 · Dec 31, 2006

Your going to get many different opionions on this topic either way you talk to folks who have over 150K and ill bet some will say hot some will say cold either way as long you change your oil it doesnt matter weither its hot or cold.

427Z06 · Dec 31, 2006

Quote:

I always drain it warm.

Just like Goldie Locks! Not too hot...not too cold.

tenderloin · Dec 31, 2006

'The oil you're pouring from your bottle doesn't have to travel through bearing clearances and pin-hole sized oil passages on the way to the oil pan'.

That is my point! It doesn't have to run through the engine cold since it was hot and has since drained into the pan.

A "cold" drain is draining the oil that has been in the pan..once hot, now cold. That is why I mentioned how easily and thoroughly "cold" oil pours from a bottle. It comes out just as easily from a relatively large opening in the pan...More old oil is drained as are more particulates.

Might be a minor deal, but on BITOG many minor deals are discussed too the cows come home.

427Z06 A happy and a prosperous New Year to you and yours.

427Z06 · Dec 31, 2006

Quote:

'The oil you're pouring from your bottle doesn't have to travel through bearing clearances and pin-hole sized oil passages on the way to the oil pan'.

That is my point! It doesn't have to run through the engine cold since it was hot and has since drained into the pan.

And the circle is completed...or, Déjà Vu...if you like.

Just don't start your cold engine before you drain it.

Quote:

427Z06 A happy and a prosperous New Year to you and yours.

And a happy and a prosperous New Year to you and yours.

4esorselrahc · Dec 31, 2006

It's recommended to drain the oil while it's hot. It will flow out more freely.

JHZR2 · Dec 31, 2006

change it hot... some would say change it hot and change it often... and if youre not doing UOA, thats likely the best suggestion.

JMH

UncleS2 · Dec 31, 2006

I always drain oil hot. No exceptions, not even the lawn mower.

deven · Dec 31, 2006

Ok, I will compromise. I change not hot nor cold, lukewarm/cold.

Quickbeam · Dec 31, 2006

Bryanccfshr Universal Seconds

tmus2122 · Dec 31, 2006

Quote:

I always drain oil hot. No exceptions, not even the lawn mower.

Hotter the better, even if I get burned.

tenderloin · Dec 31, 2006

This is sooo hilarious. On a cold drain you are only draining the oil from the pan. It does easily drain out. The hot oil on shut off ends in the pan. It is so simple, yet years of "changing it hot" have clouded your minds. Stop and think for a second. One is only draining the oil (more oil than a short hot oil drain) from the pan. Cold oil flows freely..and with enough current to sweep away particulates that are no longer suspended (if any) in the oil.

More dirty oil in the pan to be drained...less in the engine.

Change oil Hot or Cold?

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