I keep a box of Harbor Freight lates gloves in the garage for oil changes , etc. I should have started doing that years ago .
Prefilling Oil Filters & How many Changes until all old oil is gone
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Owen Lucas
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I made a separate video for those to showcase how many changes it took to clear out the sump as I wanted clear oil for the transparent oil filter.
"I reinstalled the fuel pump fuse." I said to too fast in the clip. I figured these glass filters were not going to hold with the running engine oil pressure of 4-6psi the 2AZ-FE generates on idle so I ran the engine with the starter to get the oil pressure flowing. I saved the best for last and was worried the beaker would shatter but am glad it just came apart instead.
At 0* that might be quite the show!
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You should hear my John Deere F510 complain at 10F with 0w40.
no, LOL. They just get unplugged. Should've been more clear.
I change mine with the oil slightly warm so that it drains faster but not so much that the oil or engine is scalding hot. As for how much old oil and contaminants you get out, if youre talking 4 or 5 quarts and theres maybe half a quart of old oil left in the engine, Id say 3.5 or 4.5 quarts of new oil and a new filter should be able to dilute and filter out enough that its not going to hurt that engine.
As for prefilling vs not, I prefill and I also blip the key a few times before I actually start it to prefill as much as possible and limit dry startup time. The 1st time that I changed oil on my Accord I didnt prefill the filter and just fired it up and it took almost 3 seconds before the low oil light went out and the engine stopped rattling. When I prefill and blip the key, it still rattles a little bit but its like half a second. If it does nothing more than make me feel better and be less anxious about dry startup time, its worth it.
As for prefilling vs not, I prefill and I also blip the key a few times before I actually start it to prefill as much as possible and limit dry startup time. The 1st time that I changed oil on my Accord I didnt prefill the filter and just fired it up and it took almost 3 seconds before the low oil light went out and the engine stopped rattling. When I prefill and blip the key, it still rattles a little bit but its like half a second. If it does nothing more than make me feel better and be less anxious about dry startup time, its worth it.
From what I have learned here on BITOG, I don't think there is much truth to that. Modern motor oils are formulated to hold contaminants in suspension.
I made those videos!
Basically, draining oil when the engine is hot will get you the most oil out for the time you want to spend. 1 hr hot drain = extra 100ml vs 8 hrs for the same amount cold on and 05 Toyota 2AZ-FE. Does this matter in the big scheme of things? I don't think so, just an interesting experiment, but if you want to drain you oil overnight, go for it.
I like to change my oil when it's hot but not dangerous to the touch. Someone mentioned a while back hot synthetic oil is very carcinogenic IIRC and some chemicals get into your pores.
From what I have read, it is not the motor oil that is carcinogenic, but rather, all the engine contaminants that are suspended in the motor oil. So, it is used motor oil that is carcinogenic, regardless of whether it is dino or synthetic.
A used oil will likely be thicker when cold than when brand new, so the test doesn’t represent real life scenarios.
The MityVac likes warm to hot oil. Of course I prefer working on a cool engine.
I believe if you change your oil at 5K intervals you will be fine either way.
I believe if you change your oil at 5K intervals you will be fine either way.
Hot or cold I let it drain until it has that dang tiny stream that any breeze blows oil all over everything.
I never prefill oil filters even on my Chevy with around 130,000 miles of which the oil filter is vertical, it has an oil pressure gauge and gets oil pressure within 5 seconds.
There is 2 Toyota's sitting in my driveway right now, one with 140,000 miles and one with 280,000 miles both horizontal filters and not prefilled on their original engines running strong.
Residual oil left over is plenty. Oh and if anyone is curious I change my oil cold.
There is 2 Toyota's sitting in my driveway right now, one with 140,000 miles and one with 280,000 miles both horizontal filters and not prefilled on their original engines running strong.
Residual oil left over is plenty. Oh and if anyone is curious I change my oil cold.
Oh it is you... Cool that you are here!I made those videos!
Basically, draining oil when the engine is hot will get you the most oil out for the time you want to spend. 1 hr hot drain = extra 100ml vs 8 hrs for the same amount cold on and 05 Toyota 2AZ-FE. Does this matter in the big scheme of things? I don't think so, just an interesting experiment, but if you want to drain you oil overnight, go for it.
I like to change my oil when it's hot but not dangerous to the touch. Someone mentioned a while back hot synthetic oil is very carcinogenic IIRC and some chemicals get into your pores.
Driving a "domestic" vehicle I just do the clear flood method and then let off the pedal from the floor while it's still cranking after 5 or so seconds. The ECU in my van keeps it cranking until it starts or until the time out period like 20 seconds later. So 5 seconds or so I think is enough, I let off the pedal and then let it start up. I figure it's probably enough time to fill the PentaStar's oil filter cartridge at the top of the engine.
I like to change it cold, when the vehicle has sat overnight and the oil has drained down to the pan, all its going to.
Never prefill filters, but also rarely had anything where the filter is screwed on going straight up, where its possible to prefill it.
Never prefill filters, but also rarely had anything where the filter is screwed on going straight up, where its possible to prefill it.
A short story about oil changes.
Many many years ago now, a mechanic of mine was doing an oil change when in came a couple of work safe inspectors. The first question they asked me, and him, was how hot is the oil when he pulled the drain plug.
I said well about air temperature of the shop right now is my guess, since the trucks in for service this morning, have all sat in the shop since yesterday.
They said that was good, and not to do oil changes when really hot, because it's a safety issue, and people get burned doing that.
The way I see it is this, park the trucks in the shop that night, and it sits there for lets say 12 to14 hours, about as much oil as is ever going to drain down to the pan has, so when you pull the drain plug all the crap freely flows out.
By starting it, you pump the oil back through the engine, and then if you pull the drain plug, a bunch remains up in the engine for hours.
Plus I don't want my staff doing hot oil changes, because of the burn risk.
I've done my own vehicles hot and cold, but preferably cold unless I have no choice.
Many many years ago now, a mechanic of mine was doing an oil change when in came a couple of work safe inspectors. The first question they asked me, and him, was how hot is the oil when he pulled the drain plug.
I said well about air temperature of the shop right now is my guess, since the trucks in for service this morning, have all sat in the shop since yesterday.
They said that was good, and not to do oil changes when really hot, because it's a safety issue, and people get burned doing that.
The way I see it is this, park the trucks in the shop that night, and it sits there for lets say 12 to14 hours, about as much oil as is ever going to drain down to the pan has, so when you pull the drain plug all the crap freely flows out.
By starting it, you pump the oil back through the engine, and then if you pull the drain plug, a bunch remains up in the engine for hours.
Plus I don't want my staff doing hot oil changes, because of the burn risk.
I've done my own vehicles hot and cold, but preferably cold unless I have no choice.
@StevieC, I've always bought into the idea that "changing your oil without changing your filter is like having a shower and putting your dirty underwear back on".
As such, I've always changed the filter with every OC.
However, I've come to realize* that there's no problem with leaving the filter on for at least two OCs (presuming it's not so full that it will go into bypass mode).
The rationale is that there is typically 0.5 - 1.0 l of old oil left in the engine, even if you do change the filter. The difference in oil volume between a "wet" (has been in service) and "dry" (engine has been rebuilt and not yet filled) engine is usually way more than what the filter holds.
Let's make up some numbers on a mythical modern engine:
Dry capacity: 6.0 l
Wet capacity w/o filter change: 5.0 l
Wet capacity w/ filter change: 5.25 l
So for a normal OC with a filter change, you're draining 5.25 l and leaving 0.75 l of dirty oil in the engine (87.5% new oil).
For an OC without a filter change, you're draining 5.0 l and leaving 1.0 l of dirty oil in the engine (83.3% new oil).
(You could remove a spin-on filter and let it drain, to increase the % of fresh oil you could add. Harder to do with a cartridge filter, but quite easy with a Mazda5 which has a drain plug on the plastic housing.)
If you were really set on having really clean oil without tearing down the engine, you could run the engine with new oil for a short time, drain the mixed oil, and fill with new. Let's be really OCD and say we change the filter too:
After one OC including filter:
Clean oil 87.5% (7/8)
Dirty oil 12.5% (1/8)
After two OCs including filters:
Dirty oil = 1/8 x 1/8 = 1/64 = approximately 1.7%
Clean oil = 63/64 = approximately 98.3%
(I actually did this once after swapping in a used engine.)
* Realize, I say - still can't bring myself to actually do it.
As such, I've always changed the filter with every OC.
However, I've come to realize* that there's no problem with leaving the filter on for at least two OCs (presuming it's not so full that it will go into bypass mode).
The rationale is that there is typically 0.5 - 1.0 l of old oil left in the engine, even if you do change the filter. The difference in oil volume between a "wet" (has been in service) and "dry" (engine has been rebuilt and not yet filled) engine is usually way more than what the filter holds.
Let's make up some numbers on a mythical modern engine:
Dry capacity: 6.0 l
Wet capacity w/o filter change: 5.0 l
Wet capacity w/ filter change: 5.25 l
So for a normal OC with a filter change, you're draining 5.25 l and leaving 0.75 l of dirty oil in the engine (87.5% new oil).
For an OC without a filter change, you're draining 5.0 l and leaving 1.0 l of dirty oil in the engine (83.3% new oil).
(You could remove a spin-on filter and let it drain, to increase the % of fresh oil you could add. Harder to do with a cartridge filter, but quite easy with a Mazda5 which has a drain plug on the plastic housing.)
If you were really set on having really clean oil without tearing down the engine, you could run the engine with new oil for a short time, drain the mixed oil, and fill with new. Let's be really OCD and say we change the filter too:
After one OC including filter:
Clean oil 87.5% (7/8)
Dirty oil 12.5% (1/8)
After two OCs including filters:
Dirty oil = 1/8 x 1/8 = 1/64 = approximately 1.7%
Clean oil = 63/64 = approximately 98.3%
(I actually did this once after swapping in a used engine.)
* Realize, I say - still can't bring myself to actually do it.
Hmmm....
Not too long ago I flushed my cooling system. I went from Ford dexcool to Ford yellow, and I wanted to get out almost all of the dexcool. My system takes almost 4 gallons. I drained out 2 gallons, stuff was quite pink, filled with H2O. Drove it a day and drained 2 more and replaced with H2O. I did this 4 times in 4 days. The 4th drain, the water was quite clear. I was pretty happy at #3, but #4 looked like - well, water. I'd have drunk it in a survival situation lol.
A car with a million on the clock that's had 5k OCI it's entire life will have a tiny amount of factory fill in it. I don't math very well, but if you get out 95% of the oil each change, by the time you get to the 3rd change you have a teenyieth amount percentage wise of OG oil left in it.
^^^Number_35 math is much better than mine...... He doesn't have to say things like 'teenyeth' because he maths.
Not too long ago I flushed my cooling system. I went from Ford dexcool to Ford yellow, and I wanted to get out almost all of the dexcool. My system takes almost 4 gallons. I drained out 2 gallons, stuff was quite pink, filled with H2O. Drove it a day and drained 2 more and replaced with H2O. I did this 4 times in 4 days. The 4th drain, the water was quite clear. I was pretty happy at #3, but #4 looked like - well, water. I'd have drunk it in a survival situation lol.
A car with a million on the clock that's had 5k OCI it's entire life will have a tiny amount of factory fill in it. I don't math very well, but if you get out 95% of the oil each change, by the time you get to the 3rd change you have a teenyieth amount percentage wise of OG oil left in it.
^^^Number_35 math is much better than mine...... He doesn't have to say things like 'teenyeth' because he maths.
@mr_boring (which many might say should be my BITOG handle), you can do this! And teenyeth is a good qualitative description of the remaining amount after a few drains and fills.
If you drain 95% of the used oil, you've got 1/20th left.
When you do it again, you have 1/20th of 1/20th = 1/400th of the original left.
Third time you're down to 1/20th of 1/400th = 1/8000th of the original, and so on. That's certainly a teenyeth.
You've got this.
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