warm engine before changing oil? why.

Discussion in 'Lawn Mowing' started by grass disaster, Jun 28, 2005.

  1. grass disaster

    grass disaster LawnSite Silver Member
    Posts: 2,583

    i was in a little discussion with a guy at work about this subject. i said it's best to warm up your engine before you change oil.

    he disagreed. he said that he leaves it sit over night then drains it in the morning.

    what do you know about this. i'm lookin for something solid to show him i'm right.
  2. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    Warm the engine up, the warm oil drains more dirt and contaminates
  3. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    Warm oil flows like water and cold oil flows like pancake syrup. Do you want to drain the oil in 5 minutes or 5 hours? Now add this to what 6'7 330 said above and that is the answer. And thank about this when was the last time you took your car to the quick lube on the corner and they told you, you would have to leave it over night to get an oil change, it is called a 15 minute oil change not a 15 hour oil change.
  4. sheshovel

    sheshovel LawnSite Fanatic
    Posts: 5,112

    It's basic physics that warm surfaces release matter better and faster than cold ones.Think of a frying pan,does the oil flow off of it better when warm or when the pan is cold?If you cook eggs in oil and after want to clean the pan,is it better to clean it while still warm or wait tell it's cold?This is why we use warm or hot water to clean ourselves with ..
    Things that are warm clean things better and remove surface soil alot better than cold.
  5. Precision

    Precision LawnSite Silver Member
    Posts: 2,995

    As others have said warm oil flows much faster and more completely.

    But also think about a paint can. You mix it prior to painting so that all the pigments are in suspension. Same thing with changing oil. The dirt and metal are heavier than the oil so they settle out when allowed to rest. Changing the oil after the engine has been running makes it so the pollutants are still in suspension and more likely to leave the engine.
  6. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    I had not though of that one.
  7. Smithers

    Smithers LawnSite Silver Member
    Posts: 2,265

    i agree with what you guys are saying...but look at it the other way...

    since his friend was running the engine before he shut it off, everything has been drained to the bottom already. so all he has to do is let it flow out. i agree, it would take longer to drain, but if you just ran it 10 min ago, the dirt and metal shavings would be all over the rods and valves. and you would just be draining oil....not as many contaminants.

    dont you think it makes sense?
  8. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    Well I just figured out who your "friend" is. He is the guy you see when you look in the mirror. I have said my thoughts on the matter and if you bring you mower into my shop for an oil change the engine will be warmed up first. This thread is getting silly, I am going to find a new one to post to.
  9. Smithers

    Smithers LawnSite Silver Member
    Posts: 2,265

    i was reffering to the friend that he was talking about in his original post.
  10. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    OH!, my bad. I got the two posters mixed up. I got you and grassmasterLLC
    mixed up there, sorry about that. That message was meant for grassmasterLLC and his original post. Sorry, :blush:

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