wholdguy 73 #1 Posted November 23, 2019 Here is a question that does come up often. When it's time to change the oil, some say to change hot oil and others say to only change cold oil. Which is best and why? Is there a different answer if you have a Kohler, Tecumseh or Onan? G. Share this post Link to post Share on other sites
pfrederi 18,682 #2 Posted November 23, 2019 (edited) Hot oil. The crud is in suspension not laying on the bottom where it will stay while you drain. i have never heard of draining cold oil as being the best choice Edited November 23, 2019 by pfrederi 9 1 Share this post Link to post Share on other sites
953 nut 60,057 #3 Posted November 23, 2019 I too have always run the engine a little prior to draining the oil, same deal, get the crud in suspension rather than leaving it sitting in the oil pan. 4 1 Share this post Link to post Share on other sites
rjg854 12,205 #4 Posted November 23, 2019 Warm/hot oil will also flow more easily for draining purposes. 7 Share this post Link to post Share on other sites
lynnmor 7,823 #5 Posted November 23, 2019 I have the drain pan and tools ready so I can drain immediately after turning off the engine. I do this with any and all of my engines. I then let it drain for a fair amount of time and do not consider the ten minute oil change places for cars as reputable. 2 Share this post Link to post Share on other sites
SylvanLakeWH 28,432 #6 Posted November 23, 2019 Always hot... more of the gunk is suspended and gets flushed out... 1 Share this post Link to post Share on other sites
ebinmaine 72,706 #7 Posted November 23, 2019 Another for hot. Never heard of a cold oil change actually. To be honest I hadn't considered the fact that the dirt would be better suspended but I see the point. The rate of flow of warm oil I knew of. Share this post Link to post Share on other sites
oliver2-44 10,733 #8 Posted November 23, 2019 Always warm or hot for me Share this post Link to post Share on other sites
857 horse 2,588 #9 Posted November 23, 2019 Listening to our crowd talk,,,,sounds normal to us,,,,,servicing our machines...charging the batteries and even giving them a good rinsing off and even a soapy bath....But today its different....neighbors dont even know the next door neighbors first name,,,the last thing in their mind is an oil change on the yard equipment,,,if,,,, they keep the oil full, can be a wunder,,,,,much less a filter change,,,society is changing....they know more about their cell battery life than they do for the one under their truck or cars hoods,,,that they depend on to keep them mobil,,,, even my 2 mid 30,s children are perfectly content sittting quietly,,,,,consumed with their social media,,,,,,, I wunder,,,,will they be content one day going to their social media for thanks giving and other big holidsays,,,,,, as you were gentlmen.... stay safe,,,,,,, 2 1 1 Share this post Link to post Share on other sites
tom2p 2,394 #10 Posted November 23, 2019 10 hours ago, ebinmaine said: Another for hot. Never heard of a cold oil change actually. To be honest I hadn't considered the fact that the dirt would be better suspended but I see the point. The rate of flow of warm oil I knew of. meet the contrarian lol 1 Share this post Link to post Share on other sites
peter lena 9,279 #11 Posted November 23, 2019 hot oil has a very thorough flushing / draining effect , i also use this standard on the trans axel drain and flush . i am amazed to see what " oil is left in an engine " that people think is ok . start of color change is telling you its cleaning out the crud and deposits. i use rotella 30 wt spring and summer into fall, then 5-30 over winter , for easiest starting and protection. pete Share this post Link to post Share on other sites
ebinmaine 72,706 #12 Posted November 23, 2019 4 minutes ago, tom2p said: meet the contrarian lol Is there a particular reason or is it just an old habit? Share this post Link to post Share on other sites
WildmanC120 613 #13 Posted November 23, 2019 I'm currently working on a magnum 18. The dipstick was like caramel shake. I drained that honey mess and have been running it with rotella 30w and some marvel mystery oil. Run it for 5-10 minutes and let it get warm and get all the grid suspended in the oil then drain it. So yeah...another vote for warm/hot oil. Share this post Link to post Share on other sites
tom2p 2,394 #14 Posted November 23, 2019 better to change oil when hot (warm) - but I often change when cold I don't like working on a hot engine and it can be a pain to install a filter on an Onan twin ... ya gotta get up close and personal with the filter install ... especially when you are orienting the filter on its path to it's home (and often a small amount of oil will drip out) and when I do change oil when cold - I often pour some oil into the engine while the drain plug is off to flush any contaminants laying in the bottom (until oil is clear if not already) still prob not as good as oil change when warm - but I still prob get 98% benefit yes - I'm the odd ball changing oil when cold - but zero burns so far lol and remember - a zillion race engines get oil changes when cold - because they often don't have ability to start them Share this post Link to post Share on other sites
tom2p 2,394 #15 Posted November 23, 2019 (edited) 26 minutes ago, ebinmaine said: Is there a particular reason or is it just an old habit? just an old bad habit lol after cutting grass for 3 hours or whatever - often too pooped or run out of time (and/or daylight) and I don't like to start an engine for a short period - just to change oil or whatever I want that old oil out of there - don't want to run it one more time with that old oil ! lol Edited November 23, 2019 by tom2p Share this post Link to post Share on other sites
tom2p 2,394 #16 Posted November 23, 2019 (edited) not only do I often change oil when cold - I set my mower deck with front slightly up ! ( rear discharge deck ) sheesh I might be placed on double secret probation ! the grass clippings are better spread / dispersed when front of the deck is raised slightly (on rear discharge deck) - observed this over a long period of time when (at the time) I cut almost primarily with a RD deck maybe because the deck is raised and mower blades are cutting less grass ? whatever ... ? ... yard looks better ... less or little to no clumping I don't do this with side discharge decks - but I'm tempted Edited November 23, 2019 by tom2p Share this post Link to post Share on other sites
stevasaurus 23,281 #17 Posted November 23, 2019 I'm not sure, but I think Howard just solved all of the world's problems in one post. I always knew the world's problems were about OIL, but I did not know that changing it would fix everything. Thanks Howard!!! 2 1 Share this post Link to post Share on other sites
Stormin 9,985 #18 Posted November 23, 2019 Hot for me when changing. Share this post Link to post Share on other sites
squonk 43,842 #19 Posted November 23, 2019 I change it hot. If I have time, after draining I replace the plug and add a cup of Seafoam and let it sit another 10 min then drain that out to remove more crud. Then if I remember to put the plug back in I add 30W Rotella . If I remembered to put the plug in it doesn't end up on the floor! 3 Share this post Link to post Share on other sites
pfrederi 18,682 #20 Posted November 23, 2019 I tried that on one of my big tractors once about a gallon of Rotella 15w-40 on the floor 3 Share this post Link to post Share on other sites
lynnmor 7,823 #21 Posted November 23, 2019 1 hour ago, tom2p said: not only do I often change oil when cold - I set my mower deck with front slightly up ! ( rear discharge deck ) sheesh I might be placed on double secret probation ! the grass clippings are better spread / dispersed when front of the deck is raised slightly (on rear discharge deck) - observed this over a long period of time when (at the time) I cut almost primarily with a RD deck maybe because the deck is raised and mower blades are cutting less grass ? whatever ... ? ... yard looks better ... less or little to no clumping I don't do this with side discharge decks - but I'm tempted Actually it says in the manual to set the 42" deck level to 1/8" up in front, contrary to popular belief. manual Share this post Link to post Share on other sites
adsm08 3,259 #22 Posted November 23, 2019 6 hours ago, 857 horse said: Listening to our crowd talk,,,,sounds normal to us,,,,,servicing our machines...charging the batteries and even giving them a good rinsing off and even a soapy bath....But today its different....neighbors dont even know the next door neighbors first name,,,the last thing in their mind is an oil change on the yard equipment,,,if,,,, they keep the oil full, can be a wunder,,,,,much less a filter change,,, I never change the filter on either of my tractors. Share this post Link to post Share on other sites
wholdguy 73 #23 Posted November 26, 2019 Okay, so back on the topic of Oil Change here. I agree with most everyone who wrote something that to change oil while hot is best. That's what I always try to do on all my small engines and on my vehicles too. I think it was one of my boys who was trying to decide about cool oil or hot oil and I told him that the hot oil change is best. Thanks to all. G. Share this post Link to post Share on other sites
tom2p 2,394 #24 Posted November 26, 2019 On 11/23/2019 at 12:34 PM, lynnmor said: Actually it says in the manual to set the 42" deck level to 1/8" up in front, contrary to popular belief. manual so no double secret probation for me ! Share this post Link to post Share on other sites
tom2p 2,394 #25 Posted November 26, 2019 On 11/23/2019 at 4:05 PM, adsm08 said: I never change the filter on either of my tractors. ok ... I got nuthin Share this post Link to post Share on other sites