JSM Posted June 19, 2008 Share Posted June 19, 2008 My dad is a Mechanical engineer in his late 60's. He always told me to change the oil when it is cold so all the used oil can settle in the pan and it is much easier to work on. I'm curious if doing this cold could cause more wear to the motor, being that once drained and cold, oil presure is needed to be built up before parts begin to be lubricated. Where as warm, everything has a nice coating from recently being run. Thoughts? Or even if there is more wear, the difference is not significant. Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted June 19, 2008 Share Posted June 19, 2008 I always like to change my oils warm after settling for few minutes. The way I see it is that oil is less viscous when warm making it easier to move or flow down to the oil pan. I don't think it really makes a difference on how you do it. The only exception is if an engine has been sitting for a long time and isn't primed before running. Quote Link to comment Share on other sites More sharing options...
alexdeprat Posted June 19, 2008 Share Posted June 19, 2008 Remember the 5min flush can (is actually diesel fuel) that some auto parts have on their shelves, well I use it every time I change the oil on my engines, of course according to the steps to use it you have to warm up the engine for 5min:shock:, I be honest, that stuff works like a champ! It truly cleans the engine:mrgreen:. Alex Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted June 20, 2008 Share Posted June 20, 2008 What ever is convieniant. For me that usually means a warm engine, because I will usually decide to change it on my way home, or as I bought the oil, and change it as soon after getting the car up on jackstands or up on a hoist. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted June 22, 2008 Share Posted June 22, 2008 Diesel fuel? I use B12 Chemtool and add that---cleans like the insides of your engine like Cholera cleans your intestines. Anyway, it works well and I usually warm up the engine. I was going to be 'funny' and say that prefer to drain the oil when the engine is darn hot, so I can burn my fingers and hands, look like an idiot as I scream from the under the car (don't ask), but I thought that would be foolish.... I usually drain the oil when the engine is cold, but I never think about this thingie... Davy Quote Link to comment Share on other sites More sharing options...
Careless Posted June 22, 2008 Share Posted June 22, 2008 how do you use the B12 Chemtool? I generally like to drain oil warm, so it flows out of the pan a lot smoother Quote Link to comment Share on other sites More sharing options...
Jeremy82zx Posted June 22, 2008 Share Posted June 22, 2008 My dad (back in the day) used to put in about a gallon of diesel(after he drained all of the oil but left in the oil filter just so there was some oil). And idle it for 5 minutes, then drain. Quote Link to comment Share on other sites More sharing options...
alexdeprat Posted June 22, 2008 Share Posted June 22, 2008 My dad (back in the day) used to put in about a gallon of diesel(after he drained all of the oil but left in the oil filter just so there was some oil). And idle it for 5 minutes, then drain. You know, I being adding 1qt of diesel fuel to the crankcase before an oil change for several years now to all my vehicles, now I will be very skeptical to just add diesel (a gallon) and run the engine for a few minutes after a drain. My respect to your dad, he is brave man to say the least . Respectfully, Alex Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted June 22, 2008 Share Posted June 22, 2008 Why dont you add a quart of AUTOMATIC transmission fluid about a day or two before you change the oil.. or let it run for a while then drain the oil?! ATF cleans the engine.. acts as a detergent. Quote Link to comment Share on other sites More sharing options...
alexdeprat Posted June 22, 2008 Share Posted June 22, 2008 Why dont you add a quart of AUTOMATIC transmission fluid about a day or two before you change the oil.. or let it run for a while then drain the oil?! ATF cleans the engine.. acts as a detergent. Funny that you mention ATF fluid, I actually use it to turn the crankshaft on old engines that I have in the shop, I usually dumped some into the spark plug holes for a day or two and it works as a cleaner/fluid. The thing about the ATF fluid is that it works better after a few hrs of operation, I rather change the oil and be done with it. Good call. Quote Link to comment Share on other sites More sharing options...
Bart Hoedemaker Posted June 22, 2008 Share Posted June 22, 2008 Well JSM, your dad is right, cold everything has collected in the pan, if warm 1/10 is still in the engine, as a fillm, or at least more than cold. Offcourse you can never get all the old oil out of the engine. But you can use an engine cleaner fuid if you want. Quote Link to comment Share on other sites More sharing options...
Poindexter Posted June 22, 2008 Share Posted June 22, 2008 Will cold oil drain completely from a Z engine though? I've just spent so much time doing research on oils and gear lubes, since I'm positive that they are a major factor on engine life, but I haven't found any definitive answers on this subject- so it appears that I have more reading to do. It almost seems that this might be measurable, at least on engines that burn very little oil. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted June 22, 2008 Share Posted June 22, 2008 Ive found that adding a qt of MARVEL MYSTERY OIL to the crank case KEEPS the crud in suspension and disolves a great deal of sludge, and I drain oil when its hot simply because it flows faster and tends to drag out more crud when it drains. the main thing is to do oil changes regularly (between 3500-7000 miles) and change the filters about every 3500 miles I also avoid cheap filters and add several magnets that pick up a significant amount of metalic dust over time, preventing its getting embedded in the bearings http://www.digitalcorvettes.com/forums/showthread.php?t=92038&highlight=magnets http://www.digitalcorvettes.com/forums/showthread.php?t=80384&highlight=magnets BTW Id suggest not useing pariffin rich oils, quaker state is one example, that tends to have high parriffin content, these tend to leave a significant film that builds up over time into sludge if not changed frequently , keep in mind MARVEL MYSTERY OIL has high concentrations of solvents and friction reducers that tend to keep crud in suspension Quote Link to comment Share on other sites More sharing options...
Savage42 Posted June 22, 2008 Share Posted June 22, 2008 Why dont you add a quart of AUTOMATIC transmission fluid about a day or two before you change the oil.. or let it run for a while then drain the oil?! ATF cleans the engine.. acts as a detergent. Yep, I've added a quart of ATF before changes for quite some time. Typically, at 5k miles between oil changes, the car is about a quart low, anyway. I run it for a couple hundred miles and seems to work very well and is pretty inexpensive. Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted July 22, 2008 Share Posted July 22, 2008 I think this is all just personal preference to be honest. I usually wake up in the morning, go get breakfast, come back, eat, jack the car up with the drain bolt pointing down and change the oil. This way, the oil is warmed to flow easier, but the car is not so hot that curse words fly when I burn myself on the engine parts. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 23, 2008 Share Posted July 23, 2008 how do you use the B12 Chemtool? Simply add the B12 Chemtool to the oil and run it before draining. Cleans up very nicely. Oil runs out rather quickly too Davy Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 29, 2008 Share Posted July 29, 2008 My dad is a Mechanical engineer in his late 60's. He always told me to change the oil when it is cold so all the used oil can settle in the pan and it is much easier to work on. I'm curious if doing this cold could cause more wear to the motor, being that once drained and cold, oil presure is needed to be built up before parts begin to be lubricated. Where as warm, everything has a nice coating from recently being run. Thoughts? Or even if there is more wear, the difference is not significant. That seems a very strange answer from an engineer. Hot oil is thinner and will drain out better. No one says you have a time limit on how long you keep the oil plug drained. I always drain hot and let it sit for a short while while I inspect the engine, check other fluids, scheme about the next thing to do to the car, etc. I also think that people don't pay enough attention to the angle the car is sitting at compared to the bottom of the oilpain, etc. Some cars can easily leave a substantial puddle in the pan just because it doesn't drain all the way. I never let a car run to 7 or 10k miles. That's ridiculous. Sure, some newer engines can supposedly go 10k or 15k between changes, but that'll just get you past the warranty with minimal cost/hassle of oil changes. What other motivation would you expect a car manufacturer to have? A friend of mine is a Beemer tech. They supposedly go 10 or 15k between changes and the computer tells you when to change oil. However, the cars that come in like clockwork every 10 or 15 look like black chocolate. I change at 3k or 4k at max. Quote Link to comment Share on other sites More sharing options...
Wedge Posted July 29, 2008 Share Posted July 29, 2008 I usealy go get the oil and filter go back home leave the car to cool for 15 min more or less and jack the car drain then the filter then i fill the filter with oil till its almost full ( oil filter relocated vertically ) then plug it then fill . I will try to find something like B12 chemtool and try it on my next oil change . Quote Link to comment Share on other sites More sharing options...
jamunm90 Posted August 5, 2008 Share Posted August 5, 2008 Also, prime the oil filter by placing about a quarter quart of oil in it and slosh it around, and the oil pressure will come up much faster. Easy on the turbo cars that have the oil cooler and the vertical filter mount, but harder on the usual side mounts, as if you use too much it will pour out and make a mess. Just enough to saturate the filter media. I do mine hot after it has sat for an hour. Don't worry about that last little bit. Also, if you're using a good full synthetic, you can go about 3K additional miles than the organic dinosaurs squeezing oil. If you're running a turbo, synthetic is all you should be using IMHO... Quote Link to comment Share on other sites More sharing options...
blue72 Posted August 22, 2008 Share Posted August 22, 2008 I personally enjoy having hot motor oil run down my arm and into my shirt when removing the drain plug. I think its just a matter of convenience to change the oil when its warm. Usually I at least have to move the car into position before the procedure anyway, or have just come back from the auto parts store where I bought the oil and filter. Seems like the same deal as changing transmission fluid. You can't get all of the old stuff out by just draining and filling what with the torque converter and valve body and all. You accept that some motor oil will be left in the block when changing, and it probably helps lubricate on startup either way you do it. Quote Link to comment Share on other sites More sharing options...
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