"Oil Scalding" - another myth or fact?

Is it true that during oil change it is better for the fresh oil to be poured into cool engine instead of hot? I know that pouring relatively cold oil into hot engine during oil change may cause some degree of thermal shock to top engine components, but is it the same shock for the oil? I read it on Usenet newsgroups so I won't be surprised if it's total BS. Thanx
 
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666
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Triad, NC
I vote for TOTAL AND UTTER BULLPOOPIE!!! Reading this kind of myth gives me diarreah. [Mad]
quote:
Originally posted by TheNauseator: Is it true that during oil change it is better for the fresh oil to be poured into cool engine instead of hot? I know that pouring relatively cold oil into hot engine during oil change may cause some degree of thermal shock to top engine components, but is it the same shock for the oil? I read it on Usenet newsgroups so I won't be surprised if it's total BS. Thanx
 
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13,132
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By Detroit
I am thinking that by the time you drain out the old oil and R&R the filter the engine will have cooled enough that this should not be an issue. However, I don't think it would be a problem even pouring makeup oil into a hot running engine. Don't oil temps get much higher than that where the oil is scraping off the cylinder walls and it doesn't scald? The makeup oil would be well warmed up before it got that far anyway. I'd be more concerned about damaging the oil additives if the engine overheats. I think I once "cooked" some of the plastic viscosity index improvers in my motorhome's oil by letting it idle for over an hour on a hot summer day and the water temp gauge was way over to the right. That oil was pretty bad when I drained it.
 
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301
Location
SE Michigan
OMG! Never thought of that..Now I need to cool my engine and warm the oil??. I guess if the engine were red hot while pouring the oil in..It could cook the oil....Maybe we should all warm our beer to 98.6f to prevent thermal shock also.....yep,,, thats what I want to do........ Somtime people's theroies are just a little to much..... [ December 20, 2003, 01:07 AM: Message edited by: 94MaxGXE ]
 
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Louisville, KY
While I agree this is likely not a problem I admit to once heating up a quart of oil to approx 200F. this was to add to an engine on cold start to provide some lubrication on a -40F minnesota mid winter morning. ( I knew the car was a quart down as I had checked night ebfore).. I dont know how much it accomplished, but it made me feel better and I imagined that my total oil would be clearly warmer now better avble to circulate as well as warming top engine components slightly. Fred... [Smile]
 
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Bolivia
The parts where you pour the oil are not nearly as hot as turbos and cilinders, and you don't normally pour at high rates (wouldn't go down the tubes fast anyway) so by the time the oil gets down to the pan it will have have taken a little of the temperature, but not much. No way to damage either the oil or the engine. This isn't like adding cold water to the block.
 
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8,711
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Nothern USA
Definitely no problem in engines that have a separate tube leading directly to the crankcase. I really doubt there would be much trouble where the oil goes in aa hole it the valve cover. If you are worried, drive with some moderation as you come home before changing the oil. Your neighbors may even appreciate it. Oil does not have the heat capacity or transfer of water. Adding cold water to an overheated engine can cause problems. Oil to a warm, but not over heated engine, surely not.
 
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1,533
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Ephraim
quote:
Originally posted by Ray H: Add this topic as another entry in a long list of worries that keeps me awake into the wee hours of the morning... [Roll Eyes]
You TOO... The engine is not like a Glass POT that has been setting on a RED-HOT stove for about an hour with nothing in it, then placed into the cold wet sick... Now, maybe, if the AC line is snipped after a long hot ride, and the freon shoots all over the block, Hummmm sounds like an experiment!
 

TheNauseator

Thread starter
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54
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San Francisco Bay Area
This goes to show everyone what kind of BS can be found on Usenet. BTW, while doing a search on Pennzoil I found about 300 opinions that "using Pennzoil is like adding liquid sludge to your engine." [Roll Eyes] The ignorance of some people...... This scalded oil idea is quite creative, don't you think? [Razz]
 
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1,533
Location
Ephraim
quote:
Originally posted by TheNauseator: ---- I found about 300 opinions that "using Pennzoil is like adding liquid sludge to your engine." ----
It is, it's true, and so is any other oil like it for that matter... ALL oil is, IS sludge that's been treated and treated and treated (refined) to make it stay un-sludged, until it gets too contaminated and returns to it's natural state. They create motor oil from sludge, and the oil has an persona of an oil attempting to revert back to it's former state... IMO -SYNs are similar but just don't turn back as fast for many reasons. [ December 21, 2003, 05:32 PM: Message edited by: Robbie Alexander ]
 
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Spring HIll
TheNauseator, Interesting topic, I wouldn't have thunk it in a month of Sundays. I can see where people know absolutely nothing about car maintenance would think this were true. But we here at BITOG know better! [Big Grin] Would the converse of this be true? Should I toss my jug of Chevron in the microwave for a few minutes to get it good and hot to add to the engine? (Man, it would be a mess if that bottle exploded in there.) This would open up a new can of worms: microwave time charts of how long to leave oil in there prior to adding to the crankcase. Would DELO's take longer to warm up compared to 5w oils? Synthetic warming charts?
 
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4,478
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Southern California
quote:
Originally posted by ToyotaNSaturn: ...Should I toss my jug of Chevron in the microwave for a few minutes to get it good and hot...
Careful what you suggest - someone might actually try it. My better half tried "hard-boiling" a raw, uncracked egg in the microwave oven. [email protected] egg went off like a freakin' grenade. Blew the door clear across the kitchen and we were cleaning spattered egg off everything in there - floor, cabinets, ceiling, window, refrigerator, stove, counter tops, etc. - for hours. Luckily no one was present in the kitchen when this happened. Heard reports later that about that time people in Canada cocked their heads, looked up, and queried, "What was THAT?" When I delivered what was left of the microwave oven to the recycling can at the curb, my nosey neighbor with the thick Chinese accent wandered over, looked, and said, "Oh, you wife try hard-boil egg in microwave, too, yes?" Proof that the concept of misery loving company transcends cultural boundaries, I guess.
 
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425
Talk about over-thinking a task!
quote:
Should I toss my jug of Chevron in the microwave for a few minutes to get it good and hot to add to the engine?
Microwave energy will not heat oil. In an oven, the emitter (a cavity magnaetron) is tuned to a frequency which will resonate water molecules, it will have little or no effect on the hydrocarbon chains.
 
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666
Location
Triad, NC
I had a dream last night.......someone was torturing my prized stash of GC in the basement on red hot cylinder heads, scalding its pristine esters until they were no more ..... I woke up with a scream and had to go downstairs to check out everything was alright with my jugs of GC ..... luckily it was just a dream .... [Big Grin]
 
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43,676
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'Stralia
quote:
Originally posted by TSoA: Talk about over-thinking a task!
quote:
Should I toss my jug of Chevron in the microwave for a few minutes to get it good and hot to add to the engine?
Microwave energy will not heat oil. In an oven, the emitter (a cavity magnaetron) is tuned to a frequency which will resonate water molecules, it will have little or no effect on the hydrocarbon chains.

um, are you sure about that ? check your tupperware containers, and look for the pitting. It's where the oil sits on the surface of the watery food, gets super hot and melts the plastic. microwaves are good for melting lanolin for gun lube, heating diff oil etc etc
 
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43,676
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'Stralia
Of course, the pitting could be that I only cook with a good group V based oil, and the solvent action attacks my "microwaveware". Yeah, that could be it. [Coffee]
 
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8,711
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Nothern USA
How about the chilling effect of compressed air going in warm tires? Could lead to warping. [ December 22, 2003, 09:45 AM: Message edited by: labman ]
 
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656
Location
Massachusetts
Somebody definately did not think about that rumor carefully enough before starting it. Oh it sounda all well and good, but if the engine is so hot that the oil scalds and could possibly crack the head due to thermal shock, than the old oil would have to be of similar temp as the engine. Ever drain oil out right after a good long car ride? Yep, hurts doesn't it. If the oil is cool enough to drain, than the engine is certainly cool enough for new oil to be poured in.
 
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