comancheman Posted June 1, 2009 Share Posted June 1, 2009 can anyone explain why you are supposed to warm up your car before you change oil? it never made any sense to me. i understand the oil flows better but i usually park facing up an incline overnight so as much old oil as possible is in the back of the pan and not in the head and cylinders. i know that neither will make any significant difference but I'm anal about my oil changes and it seems warming up the oil is what every manual i have ever read says. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted June 1, 2009 Share Posted June 1, 2009 Warming up the engine and oil allows all the floating particulate matter in the engine to be held in suspension and thus be removed from the engine when the oil is removed. It has nothing to do with its flow properties. When your oil sits, the particulate settles to the bottom of wherever the oil is...head, oil pan...etc. Warming it up and allowing it to flow gets that matter moving and makes it easier to remove. Hope this helps. If you are anal about your oil changes you would want to do this! Link to comment Share on other sites More sharing options...
brdhntr Posted June 2, 2009 Share Posted June 2, 2009 :agree: good explanation. i change the oil when it's warm vs cold. if you run a cleaner through when you are doing an oil change, it works much better when you add it to warm oil and let it run 10 minutes or so before you pull the plug. just remember to let it cool a bit or use gloves. warm oil is good, hot oil is bad when you pull the plug. Link to comment Share on other sites More sharing options...
comancheman Posted June 2, 2009 Author Share Posted June 2, 2009 i see what your saying but i still disagree. yes when the oil is warm it holds the particulate matter in suspension that would normally settle on the head or in any other recess but even still there is going to be the same amount of oil that settles in the head when the car is shut off after "warming" as there was when you shut it off the day before so the same amount of particulate matter remains in the engine. Link to comment Share on other sites More sharing options...
aemsee Posted June 2, 2009 Share Posted June 2, 2009 Let's see...you asked for an explanation regarding changing your oil when it is warm vs. cold. Das gave you a very concise explanation that jibes with everything you have read. Yet you insist that he his wrong (as well as everyone else). You are obviously not looking for information, just validation. :shake: Link to comment Share on other sites More sharing options...
comancheman Posted June 2, 2009 Author Share Posted June 2, 2009 I'm not trying to be argumentative at all, I'm just trying to make it make sense in my thick head. ive always wondered about this and yes he gave me an explanation but it still doesnt seem logical to me. its really not a huge deal. i was just wondering. Link to comment Share on other sites More sharing options...
aemsee Posted June 2, 2009 Share Posted June 2, 2009 Don't just think pieces of metal and stuff as far as debris goes. There are also contaminates that will jell cold but melt and mix in with the oil when it is warm. How much does it really matter? Who knows. More important that you just change it on a regular basis. Do you fill your filter before you install it since you let the motor drain down for an extended period of time? Link to comment Share on other sites More sharing options...
comancheman Posted June 2, 2009 Author Share Posted June 2, 2009 i always prefill although difficult and messy (who knows how much actually stays in the filter) with the inverted filter and use a mobil 1 filter. i don't get any taps on initial start up so it must do something. Link to comment Share on other sites More sharing options...
DirtyComanche Posted June 2, 2009 Share Posted June 2, 2009 I often pull the plug cold. I don't really care. I imagine there will be a little sediment on the bottom of the pan, but I have trouble believing there would be a lot that wouldn't have been caught by the filter that could actually be suspended by running it. Maybe I should waste half a quart and flush a little clean oil through it when I do that, just because. Whatever, my oil change interval is way more often than recommended anyways. And pre-filling is stupid on these things. I'm dead set on running a remote mount oil filter on my XJ (when I get that far). Link to comment Share on other sites More sharing options...
HOrnbrod Posted June 2, 2009 Share Posted June 2, 2009 Yeah, I think pre-filling the oil filter is completely unnessary on Jeep 4.0 engines. It takes about two seconds after startup after an oil and filter change to reach full oil pressure. What's not stupid IMHO is using a magnetic oil drain plug. The non-metallic sediment doesn't worry me, the filter will get it, but the heavier metallic sediment often doesn't get trapped in the filter and just moves around in the oil pan basin. Every time I change oil in whatever vehicle I have (magnatic plugs in all), there is always a bit of metal shavings on the plug. Can't hurt. :cheers: Link to comment Share on other sites More sharing options...
aemsee Posted June 2, 2009 Share Posted June 2, 2009 And pre-filling is stupid on these things. Hey! Who you calling stupid! :D . I've been prefilling oil filters for 30 years Link to comment Share on other sites More sharing options...
DirtyComanche Posted June 2, 2009 Share Posted June 2, 2009 And pre-filling is stupid on these things. Hey! Who you calling stupid! :D . I've been prefilling oil filters for 30 years I mean the process, not the intention... Fill filter, flip filter over to install, spill all the oil out of the filter and onto the engine and floor, swear. With a remote setup with the filter oriented correctly, I could fill it and stick it on there without spilling it. I'd actually bother then. As it is I just grumble, put some oil on the gasket, and spin the new filter on. Link to comment Share on other sites More sharing options...
Geonovast Posted June 2, 2009 Share Posted June 2, 2009 I'm dead set on running a remote mount oil filter on my XJ (when I get that far). Those things should be factory on everything. My mom had an 85 Cavalier. In order to get at the oil filter, you had to remove the right front tire, and the unbolt a plate inside the wheel well. :doh: Link to comment Share on other sites More sharing options...
brdhntr Posted June 2, 2009 Share Posted June 2, 2009 i still say to change it when it's warm. it's also been pointed out that it does more than suspend some of the impurities. warming the engine does melt and loosen the sludge and such. yes some oil will remain in some parts of the motor, but there will still be some if the motor is cold. oil does stay in some of the areas you mentioned, even when cold. you should always find a small amount in the head, otherwise, don't start your engine. it's not possible to get all the oil out unless the entire motor is torn down. even pulling the oil pan won't get every drop of oil. if you look at the reasoning of flow, it still only makes sense to warm the engine. warm oil does flow better than cold oil. so if you warm the engine, the oil will flow out of the nooks and crannies better than if it were cold. i don't really think the flow rate is an issue, but if that's one of your questions, your better off with warm oil. if you want to get more of the oil out of your engine when changing it, you should use an addative. something that will loosen the sludge and crud up and get the oil out of more places. to do that, i've heard of the gunk 5 minute flush, using diesel fuel, running tranny fluid, and others. i run a quart of diesel fuel in the engine about every 3rd oil change. i dump it in and run the engine for 10 minutes or so. it's always worked for me. i've pulled the pan on several of my trucks to see how much of a difference it makes. the pan is definetly cleaner. either way, hot or cold, i think your only looking at minimal differences. if you want opinions though, warm is better. Link to comment Share on other sites More sharing options...
project88mj Posted June 2, 2009 Share Posted June 2, 2009 something i do is when the motor is still warm and all the oil is out and plug is off the truck. take buy an extra quart of oil and pour it in and let it run through the motor as it comes out the bottom you will find that at first the oul is still black the gradually it will clear up as the fresh oil mixes with old. once the oil you pour in comes out looking the same you can be sure MOST all the old oil is out. i don't think there is a way to get very drop of the old oil out of there but you can come really close doing this. :smart: as for getting the gunk out of there about 500-800 miles before you plan to change your oil pour 1/2 a can of seafoam in to your crank case. that stuff really works wonders... of at least it has for me :dunno: Link to comment Share on other sites More sharing options...
WahooSteeler Posted June 2, 2009 Share Posted June 2, 2009 I'm not trying to be argumentative at all, I'm just trying to make it make sense in my thick head. ive always wondered about this and yes he gave me an explanation but it still doesnt seem logical to me.its really not a huge deal. i was just wondering. So when you drain bacon grease, do you do it soon after your done and take it off the stove, or do you wait until it cools down enought that it won't run out on it's own and you have to scrape the pan? Warm = thin and runny, Cold = thick and slow. Isn't that logical enough? :dunno: Link to comment Share on other sites More sharing options...
FxRacing282 Posted June 3, 2009 Share Posted June 3, 2009 warm is good. the gunk flush seemed to work good for my old SBC. although i do NOT find it necessary to run it every third oil change but thats just me. do as you wish. it does work though. warm oil plugs come out of the pan easier... thats half the reason for me anyway. and warm cold thing. you know you drain it and when its dripping you pull the filter slide the new one and put the plug fill up. you got like 95% or more out of the engine. thats what the factory says so chances are its good enough. and don't use fram filters. the sure grip idea is awesome and i wosh every company did it, but quality control is terrible. Link to comment Share on other sites More sharing options...
comancheman Posted June 3, 2009 Author Share Posted June 3, 2009 for the record bacon grease is a little different than motor oil. I truly believe that neither method is going to make a significant difference in the longevity of our beast engines. i was just seeing what other people did and thought others should do. Link to comment Share on other sites More sharing options...
pantera1973 Posted June 3, 2009 Share Posted June 3, 2009 Direct from the Automotive Experts at Mobil Oil Corporation: Question: Any Problem Changing the Oil When the Engine is Cold? I have read that the engine needs to warm up before you do an oil change to make the oil flow better. I never did this. I just let the engine cool off overnight to let the oil settle at the oil pan, then do the oil change in the morning. Logic here is that the old oil is collected at the pan and when you drain, you get most of it, plus it is a cold engine, easier to work with. I also put some oil in the new filter so it will not be a dry start. What is your opinion on this method? Thank You. -- Alex Garcia, Franklin Lakes, NJ Answer: "We think it is best to change the oil when it has been warmed up. The reasoning being that the oil flows better, and sludge and other deposits are more likely to be removed from the oil pan." Link: http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Changing_Oil_Cold_Engine.aspx From Castrol: "Cold oil will not drain properly, so before starting work, drive your car around to raise the oil temperature to bring it to normal operating temperature." Link: http://www.castrol.com/castrol/genericarticle.do?categoryId=8264013&contentId=6003180 :smart: Link to comment Share on other sites More sharing options...
aemsee Posted June 3, 2009 Share Posted June 3, 2009 Hmmm...boy that sounds familiar :idea: Link to comment Share on other sites More sharing options...
WahooSteeler Posted June 3, 2009 Share Posted June 3, 2009 for the record bacon grease is a little different than motor oil. I truly believe that neither method is going to make a significant difference in the longevity of our beast engines. i was just seeing what other people did and thought others should do. Thanks for setting the record straight. I guess I should stop using bacon grease in my engines since it's different than motor oil. I did not know that. :dunce: Link to comment Share on other sites More sharing options...
comancheman Posted June 3, 2009 Author Share Posted June 3, 2009 by all means if bacon grease is working for you i wouldnt stop. it may clog your arteries over time though. i prefer castrol HM 10w-30. I see my opinion does not agree with the opinions of the experts at castrol and mobil. maybe next time ill give warm oil a try. Link to comment Share on other sites More sharing options...
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