Tianmo Hypersonic November 29, 2010 Share November 29, 2010 I have been thinking about this logic. Everywhere I check, I see ppl saying to warm up the car b4 oil change, because warm oil flow faster. But...........................just wondering, wouldn't the oil still flow when it is cold? Will the oil flow out lesser if it is cold? will the oil flow out the same amount when hot or cold? What happen if we change oil without warm up? Lately I overfill my EO (itchy backside), and the only way to take out some oil was to change the oil filter, because my oil filter is located high up. I went to my WS and ask them to change a oil filter, and all the mech there was like blur , one took out the dipstick and told me that just nice because my EO level show more than half. But than there are oil in the engine, as in oil all over in the engine. When cold, it show more than max on the dipstick. which means when we start engine and warm up, there are like about maybe 500ml of oil up everywhere in the engine, this oil will take some time to flow back down, if we change the oil when cold, would we be taking out more used oil? is my thought logical or am I crazy? ↡ Advertisement Link to post Share on other sites More sharing options...
Tripthipal Neutral Newbie November 29, 2010 Share November 29, 2010 I think u have a point.. I really feel like testing it out on my car now Link to post Share on other sites More sharing options...
GemLeo 1st Gear November 29, 2010 Share November 29, 2010 hi bro.. not sure what you mean exactly.. but i guess starting the engine.. to circulate the residue in the oil which has accumulate at one area when engine was stopped?? then it's more like getting more dirty stuff out from the engine. Link to post Share on other sites More sharing options...
Trex101 3rd Gear November 29, 2010 Share November 29, 2010 (edited) I have been thinking about this logic. Everywhere I check, I see ppl saying to warm up the car b4 oil change, because warm oil flow faster. But...........................just wondering, wouldn't the oil still flow when it is cold? Will the oil flow out lesser if it is cold? will the oil flow out the same amount when hot or cold? What happen if we change oil without warm up? Lately I overfill my EO (itchy backside), and the only way to take out some oil was to change the oil filter, because my oil filter is located high up. I went to my WS and ask them to change a oil filter, and all the mech there was like blur , one took out the dipstick and told me that just nice because my EO level show more than half. But than there are oil in the engine, as in oil all over in the engine. When cold, it show more than max on the dipstick. which means when we start engine and warm up, there are like about maybe 500ml of oil up everywhere in the engine, this oil will take some time to flow back down, if we change the oil when cold, would we be taking out more used oil? is my thought logical or am I crazy? Actually it's the time factor, warm oil drain dry faster then cold oil. The logic is that the mechanic will take less time servicing your car when warm compare to another car which is cold. For me, when i DIY change my car oil, i usually let it drain for 30min or more while i clean the engine bay and other stuffs 1st before topping it up. If you DIY like me and have plenty of time, i think you can drain more oil if you let it drip for 30min - 1hr. Edited November 29, 2010 by Trex101 Link to post Share on other sites More sharing options...
Tigershark1976 Turbocharged November 29, 2010 Share November 29, 2010 i usually drain out the oil when the engine is cool.... dont want myself to get burn... Link to post Share on other sites More sharing options...
ER-3682 Twincharged November 29, 2010 Share November 29, 2010 Inside the engine,there are many small grooves & holes,very difficult to drain 100% of the old oil....i would says,about 200-300ml[depends on the size of the engine],is still inside the engine. Link to post Share on other sites More sharing options...
Crazecow Neutral Newbie November 30, 2010 Share November 30, 2010 Yes, warm oil drains alot faster compared to cold oil. Thats why people recommend you to drain oil while its warm. But becareful cause the oil is really hot. When the oil is cold, you are right that you will be draining out more oil than when its hot. Cause when you leave the car overnight, the oil will flow back to oil pan, hence you will get more oil. Actually, there is a way to make the oil drain slightly faster at the expense of new oil. When you are still waiting for the last few drops of oil to drip, just pour in some new oil. This way you don't have to wait till the oil pan is dry to get rid of the old oil. The new oil will clear out most of the old oil. Link to post Share on other sites More sharing options...
Nightsky 1st Gear November 30, 2010 Share November 30, 2010 Liquid viscosity depends on temperature - at higher temperatures, oil tends to be less viscous, ie more fluid, therefore it is easier for oil to flow at slightly higher temperatures. Link to post Share on other sites More sharing options...
Ben5266 Supercharged November 30, 2010 Share November 30, 2010 Maybe is because of the capillary effect. If the oil is less thick, capillary effect is less, hence it will drain faster and drain more. Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 I think u have a point.. I really feel like testing it out on my car now test and feedback ok? Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 Actually it's the time factor, warm oil drain dry faster then cold oil. The logic is that the mechanic will take less time servicing your car when warm compare to another car which is cold. For me, when i DIY change my car oil, i usually let it drain for 30min or more while i clean the engine bay and other stuffs 1st before topping it up. If you DIY like me and have plenty of time, i think you can drain more oil if you let it drip for 30min - 1hr. I also guess is the time factor. I am going to DIY, but using the pump to suck from the dipstick. Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 bro, how much your amsoil going to increase after today huh? payday on the 3 leh. Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 i usually drain out the oil when the engine is cool.... dont want myself to get burn... more oil drained compare to warm? or the same? Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 Inside the engine,there are many small grooves & holes,very difficult to drain 100% of the old oil....i would says,about 200-300ml[depends on the size of the engine],is still inside the engine. I understand. just trying to get out as much as possible. Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 Yes, warm oil drains alot faster compared to cold oil. Thats why people recommend you to drain oil while its warm. But becareful cause the oil is really hot. When the oil is cold, you are right that you will be draining out more oil than when its hot. Cause when you leave the car overnight, the oil will flow back to oil pan, hence you will get more oil. Actually, there is a way to make the oil drain slightly faster at the expense of new oil. When you are still waiting for the last few drops of oil to drip, just pour in some new oil. This way you don't have to wait till the oil pan is dry to get rid of the old oil. The new oil will clear out most of the old oil. I actually saw 1 mech did this, brough 5L CL to the workshop, he poured in 1L towards the end as the oil was draining, stopped, and later fill up with the balance. Link to post Share on other sites More sharing options...
Tianmo Hypersonic November 30, 2010 Author Share November 30, 2010 Maybe is because of the capillary effect. If the oil is less thick, capillary effect is less, hence it will drain faster and drain more. But I was just wondering, how thin can the oil get after 20min of warm up? Link to post Share on other sites More sharing options...
Hjgfdkjhretoilkjlkjlkj Neutral Newbie November 30, 2010 Share November 30, 2010 Yes, warm oil will flow faster as its thinner. Remember the viscosicity of oil is not measured at 100C Link to post Share on other sites More sharing options...
Tigershark1976 Turbocharged November 30, 2010 Share November 30, 2010 more oil drained compare to warm? or the same? same (from visual judgement). I drain the oil for the whole night so i dont think it makes any different... ↡ Advertisement Link to post Share on other sites More sharing options...
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