That’s been the answer every time the question gets asked.
Oil Change - Hot or Cold and Oil Level Check - Hot or Cold?
- Thread starter BlueOval83
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1, We all have our opinions, I worked in a fleet operation the oil was changed in Semis, Forklifts, sweeper machines airport ground equipment etc. hot, medium or cold it didn't make a difference.
2. That idea is so foolish. You should never let the oil get that bad to worry about the oil left in the engine. You are diluting what ever amount of used oil with new oil.
3. The engine should be off for a while for all the oil to drain into the sump for example the 2.7 Ford Eco boost needs to be off for 15+ minutes for the oil to drain to the sump for a accurate oil level reading.
2. That idea is so foolish. You should never let the oil get that bad to worry about the oil left in the engine. You are diluting what ever amount of used oil with new oil.
3. The engine should be off for a while for all the oil to drain into the sump for example the 2.7 Ford Eco boost needs to be off for 15+ minutes for the oil to drain to the sump for a accurate oil level reading.
Like when people ask, Whats the best oil to use?. Seems everybody has their favorite brand and weight, and they all seem to work, so it;s appears there can be no wrong or bad brand as long as you have some oil in your vehicle. Clean or dirty also doesn't seem to make a difference. Change it at 2500,3000, 5000, ofr 10,000 miles and the motors still run.,,
2. That was the idea I got from this forum from several other long time members post in the past. Just was curious about it since I’ve seen long threads about it before.
wow! lots of interesting responses considering the amount empirical data information posted on this forum . And it is how I found this forum and joined in the first place.
You see I use to get Federal Government Mandated DATA required submission from any distributor ,refinery or other that sold motor oil in the USA that gave complete technical as well chemical information about the oil and also it performance rating . But for some reason they stopped making it readily available a few years ago? So I have to come to forums like this that has better REAL information about moto oils.
I have gotten likely hundred's of oil analysis performed from Black Stone Oil Labs and can tell you it does matter what type of oil you use for your driving habits and environment you operate your vehicle in and also the best oil and filter service intervals. The minimum should always at least be what the manufacture have listed but sooner is always better.
Oh and really the remaining old oil left in the engine after an oil and filter service is still 100% old oil NOT DILUTED. LOL
You see I use to get Federal Government Mandated DATA required submission from any distributor ,refinery or other that sold motor oil in the USA that gave complete technical as well chemical information about the oil and also it performance rating . But for some reason they stopped making it readily available a few years ago? So I have to come to forums like this that has better REAL information about moto oils.
I have gotten likely hundred's of oil analysis performed from Black Stone Oil Labs and can tell you it does matter what type of oil you use for your driving habits and environment you operate your vehicle in and also the best oil and filter service intervals. The minimum should always at least be what the manufacture have listed but sooner is always better.
Oh and really the remaining old oil left in the engine after an oil and filter service is still 100% old oil NOT DILUTED. LOL
#1 - I prefer cold. The oil is in the pan and cold engines are easier to work on. And depending on fittment, less oil filter mess... If I am using the MityVac, the oil needs to be at least warm. Hot works well...
#2 - Sure, some oil stays in the engine, especially if you leave the oil filter. Not important in my book.
#3 - Checking cold on a lever surface is best, but you may not always have this opportunity. Driveways...
#2 - Sure, some oil stays in the engine, especially if you leave the oil filter. Not important in my book.
#3 - Checking cold on a lever surface is best, but you may not always have this opportunity. Driveways...
Drain oil when still pretty warm, and let drain awhile (30 min) while removing and installing the oil filter, and checking over engine, etc.
Install enough oil to get the level near the Full mark on the dipstick ... that's after running the engine a few minutes to fill the filter and galleries.
Check oil level cold after the car has been driven and has sat all night - and do final oil level adjustment to the Full mark on the dipstick.
Install enough oil to get the level near the Full mark on the dipstick ... that's after running the engine a few minutes to fill the filter and galleries.
Check oil level cold after the car has been driven and has sat all night - and do final oil level adjustment to the Full mark on the dipstick.
1. I don't think it matters but I change mine HOT.
2. When I change oil I never fill to the full mark. Anywhere between half and full.
3. It doesn't really matter Just be consistant and do it the same every time. I check mine hot because, yes, it will show higher when hot (think of checking transmission oil).
2. When I change oil I never fill to the full mark. Anywhere between half and full.
3. It doesn't really matter Just be consistant and do it the same every time. I check mine hot because, yes, it will show higher when hot (think of checking transmission oil).
IMO if you are questioning the dipstick accuracy in hot or cold, it would be best to check the oil several times in each condition. Take notes, especially if the oil level differs between conditions. Then you will be able to check it any time in the future, hot or cold.
Engine stone cold for oil change. I could not do that on my VW as that got topside, but the rest are cold. I am not sold on oil picks stuff up while hot—if true then the filter should catch, anything finer than what the filter can catch is so fine that it will stay in suspension for a long time.
I know I change my oil long before it is worn out, thus whatever little is left in does not bother me.
I pull the dipstick with engine cool or cold. In the end it’s not a precision measurement device. Close enough is good enough, plus minus half quart never hurt anything.
I know I change my oil long before it is worn out, thus whatever little is left in does not bother me.
I pull the dipstick with engine cool or cold. In the end it’s not a precision measurement device. Close enough is good enough, plus minus half quart never hurt anything.
Oil does not wear out it only gets contaminated/dirty If you use 0w/20 it going to remain 0w20 if you use 20w50 same thing etc. etc. etc. 
I do this ... check hot and cold and know what the difference will be on my vehicles. If the oil level was filled to the Full mark on the dipstick when cold, and it's a hair above Full when hot it's really not going to matter to the engine anyway. I typically check the level cold, so I start out with the dipstick on the Full mark when cold after an oil change so I can accurately monitor the oil usage over the OCI.
1) Depending on engine, cold/hot/start may not matter:
2) previously addressed
3) Check cold.
Many many times.
These have been answered before numerous times but some explanation may be helpful.
1. When the oil is at operating temperature it holds more contaminants in suspension and it flows much faster. Both are desirable for oil changes. 5 mins of operating is not enough... better to do it after a typical drive around town.
2. When the engine is operating, it pumps a significant quantity of oil into the passages, galleys and heads. This lowers the level of oil in the pan. When you shut down the engine it usually takes at least 10 mins, if not longer, for all that oil to flow back into the pan. Most dipsticks are intended for checking oil when it is cold -- fully drained into the pan. For example, if you drive on the freeway and then check the oil immediately after pulling over, it will read low on the dipstick even when it's full. This has led many people to think their oil is low and add a quart, overfilling it. I imagine some unethical service stations have taken advantage of this to sell overpriced oil that people don't need.
Who says engineers don't have a sense of humor?
https://www.blackstone-labs.com/information/sampling-procedures/oil-changes-101/
After I posted this, i remembered that my owners manual (for the 07 Cad) specifically states that the oil should be checked with engine warm; see snip from the OM. Therefore it would probably be wise to check the OM, as suggested earlier in this thread.
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Why would you want to burn yourself? The oil filter holds all of the "crap"
The description of the process to measure fluid level is sometimes wrong in the manual?
Regarding dipstick levels, the thermal expansion of oil with temperature is roughly 4% per 100* F. For a typical engine having 5 quarts of oil, operating temp of 220* F and ambient 60* F, that's a difference of about 10 ounces of oil, or about 1/3 of a quart. e.g. .0004*(220-60)*5*32 = 10.
Waiting 10-15 minutes for the oil to drip back down into the pan after you've been driving makes a much bigger difference. I've measured this at 1/2 to 1 quart on a few different car engines.
Most dipsticks I've seen have about 1 quart difference between the top and bottom marks.
Waiting 10-15 minutes for the oil to drip back down into the pan after you've been driving makes a much bigger difference. I've measured this at 1/2 to 1 quart on a few different car engines.
Most dipsticks I've seen have about 1 quart difference between the top and bottom marks.
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