So recently my Samurai has been having coolant-to-oil leak problems again (I'm gonna replace the head or block or both this time, this is getting tiresome) and yesterday I noticed the oil is pretty fouled up, and I happen to have 4 quarts of cheapo oil and a filter in the back, so I stopped by this little car wash & oil change place at lunch to ask about a quick oil change, because dealing with waste oil is a PITA.
The guy tells me that the oil will be too hot right now to do the change 
And to come back in the morning when it will be cooler
I was like "Yeah, sure..."
I'll be the first to admit I would wait till things cooled almost all the way to pull the filter off my MR2 and depending on how late in the evening I was changing the oil, that might mean overnight. But that was because I had a nasty habit of introducing my arm to the exhaust.
I could have done it when the car was cool after swapping out the radiator, but I waited until the next day, after it had been driven a little and warmed up before I changed the oil in my dad's LS400. Should I seek help?
DuctTape&Bondo wrote:
I could have done it when the car was cool after swapping out the radiator, but I waited until the next day, after it had been driven a little and warmed up before I changed the oil in my dad's LS400. Should I seek help?
No you're doing it right. Ideally the engine should be shut off from full operating temperature just before someone starts unscrewing the drain bolt and filter while another guy unscrews the fill cap. That gets the greatest amount of old oil and gasified crankcase pollutants out.
When I managed an oil change place some folks would come in with a stone cold engine. I'd give them the opportunity to get the engine nice and hot after explaining that it'll get more oil out of the engine quicker. Basically a better oil change.
You've not lived until you change the oil on a V6, 4X4 'yota truck that just cruised in from Grand Rapids (we were on Grand River, right where M5 ended).
I tend to drive to get my engine nice and hot, pull up on the ramps and let the oil drain... depending on where the filter is i MIGHT crack it to let it drain (if I can get to it without burning myself)... then i'll come back 30 min or so later when it's drained and cooled down a little so I can actually touch anything...
i'm overly temp sensitive so working on hot cars REALLY sux
where I used to work.. I would go in 10 minutes early (after a half hour highway drive in) and and drop a catch pain under the car and drain the oil before starting work.. I would leave it open like that till lunch.. then put the plug in, change the filter, and fill...
GameboyRMH wrote:
No you're doing it right. Ideally the engine should be shut off from full operating temperature just before someone starts unscrewing the drain bolt and filter while another guy unscrews the fill cap. That gets the greatest amount of old oil and gasified crankcase pollutants out.
On the other hand, skin grafts can be expensive.
We let cars sit a minimum of 15 minutes before draining the oil. Worst are the people who are told that there will be a half-hour to hour wait before we can get their car in, so instead of doign the sane thing and going somewhere else, or going to a restaurant or something, they sit idling in the parking lot.
Yeah, I've seen some nasty burns from hot oil. Also the catalysts can be really hot just after a drive. I also learned first hand that those Nomex heat gloves and sleeves are wunnerful right up to the moment they get hot fluid on them, then you can't get the damn thing off fast enough.
kevlar burn sleeves:
I "borrowed" a pair from the valvolube joint I worked at ...about a day before I left. I dare anyone to change the oil filter in the last gen cougar without one.
Knurled wrote:
We let cars sit a minimum of 15 minutes before draining the oil.
why? that 15 min wont be enough to let the oil cool down noticeably. ANd it only takes about 2 minutes for nearly all the oil in a hot crankcase to drain to the pan.
My bike is impossible to change the oil when hot.. unless you like 3rd degree burns
2" from the 4 exhaust pipes.
I really do let the car sit for less than a minute...on the Toyota I remove the engine shields while the car's running (just watch out for those belts) then I shut down and undo to the drain plug using a spanner and keep myself as far away from it as possible when doing it, then after the oil's drained I undo the filter ('cuz it's hard to get to) and wear thick work gloves so I don't burn the E36 M3 out of myself on the exhaust.
On the Samurai it's easy, I just shut down, drop a drain pan where it will be under the drain plug and filter, undo the drain plug using the same careful spanner action then just walk up to the open hood and remove the filter.
In reply to GameboyRMH:
I was aiming for funny. Knew about the oil, didn't know about the gasified contaminants. Ya learn something all the time on this board.
I drain the pan hot/warmed up, but on cars like my IS300, I wait for the oil filter as it's in a crappy place.
Grtechguy wrote:
My bike is impossible to change the oil when hot.. unless you like 3rd degree burns
2" from the 4 exhaust pipes.
I still have a scar on my wrist from one like that. I thought the pipes were cool enough but they were not. Now I wait a little longer before changing the oil.
