Interesting Oil Change

[patrickt]

For a decade I have changed my oil the same way. I would run it so it's nice and warm, then change the oil while it's hot and just try not to burn my hand. It's always taken the same amount of oil, 8.5 quarts. Every time. But today I changed the oil, but with the engine stone cold, and not having been run since late November. After firing it up, checking for leaks, and letting it drain down for the top off, just like I always do, it took 9 quarts. Same Brad Penn 15w-40, same Moroso filter.

[rodneym]

C'mon, patrickt.
This isn't really interesting or rocket surgury.

[patrickt]

Yeah, I know, but I was tired of the Evan's Car thread, the "Would you trade your FE for a SB" thread, and the Taco Bell was closed for some reason.

[rodneym]

Maybe we can start a new thread...

"Would you straight trade your SBF Cobra for Evan's Cobra, as long as it came with a Chimi Bopolito, three Chilirooti's and a Yumbo?"

[patrickt]

Originally Posted by rodneym

Maybe we can start a new thread...

"Would you straight trade your SBF Cobra for Evan's Cobra, as long as it came with a Chimi Bopolito, three Chilirooti's and a Yumbo?"

Yes, I think that's a fair trade. Now, tell the truth, did you think I'd have an extra half quart difference on a cold engine?

[Dwight]

half quart is a lot of oil in an FE.

hum


where did it go?

Of course you checked the dip stick when it was hot and cold. Any difference in the reading?


Dwight

[patrickt]

Originally Posted by Dwight

half quart is a lot of oil in an FE.

hum


where did it go?

Of course you checked the dip stick when it was hot and cold. Any difference in the reading?


Dwight

There was a half quart more oil in the pan from having sat for four months than there is right after you have run the car for a while. You clearly get more oil out on a change when the car's been sitting for a few months.

[rodneym]

I don't know. Sitting for over three months, that oil has had lots of time to drip.

[patrickt]

Originally Posted by rodneym

I don't know. Sitting for over three months, that oil has had lots of time to drip.

See, it was interesting after all.

[jhv48]

Glad somebody finally brought this up.

I have a nine quart pan and remote oil filter and cooler. It takes 10 quarts of oil to completely fill the engine, filter and cooler when dry. The dipstick is at full, and when I drain the oil, I get 7 quarts out. Now, when I fill it back up, it takes the full 9 1/2 quarts to fill the pan and filter. WTF!

The oil level on the dipstick is exactly where it was before the oil change. So how come I only get 7 quarts out of the engine (including the oil in the filter) and it takes 9 1/2 quarts to fill it back to the full level in the dipstick?

What am I missing? Does it every time!

[rodneym]

About as interesting as watching a half a quart of oil drip over 3 or 4 months.

[RodKnock]

Oy vey. The extra 1/2 quart of oil came from Patrick's hair care product.

[Bernica]

Sounds like what might have been in the lines, filter and cooler. I'm probably wrong, but that's my first guess.

[olddog]

Originally Posted by jhv48

Glad somebody finally brought this up.

I have a nine quart pan and remote oil filter and cooler. It takes 10 quarts of oil to completely fill the engine, filter and cooler when dry. The dipstick is at full, and when I drain the oil, I get 7 quarts out. Now, when I fill it back up, it takes the full 9 1/2 quarts to fill the pan and filter. WTF!

The oil level on the dipstick is exactly where it was before the oil change. So how come I only get 7 quarts out of the engine (including the oil in the filter) and it takes 9 1/2 quarts to fill it back to the full level in the dipstick?

What am I missing? Does it every time!

If you take 7 quarts out of a bucket and pour 9.5 quarts back in and repeat, eventually the bucket is going to run over.

1) You do not get all the oil out of the filter, so you are not measuring all the oil that comes out. But that does not explain 2.5 quarts.

So after pouring the oil in, you start the engine to fill the filters and then measure. Do you start the engine prior to draining and check the oil apples to apples? I suspect the engine has sat and more oil has drained into the pan, so it measures full, but there is less oil in it than there is after you refill it. Which means that 2.5 quarts minus what you don't get out of the oil filter and drain pan, when you measure what came out, is getting burned or leaked by your engine.

You absolutely cannot put more in than you drain out, without an equal amount leaving the system in some other way, or it will overflow.

[DanEC]

Well - multi-viscosity oil is supposed to behave like a lighter weight oil at start up while cold and then as it heats up, behave as a heavier oil. So, makes sense it would drain more thoroughly when cold and thinner - right?

Not! Oil obviously continues to drain down slowly over time - probably from the galleries, oil pump, heads, etc.

[750hp]

I like to get every drop out, so after draining the oil cold, I like to start the engine and run it for a while to clear out the oil lines and passages. I find that a good rev after a couple of minutes gets the last of it out of the motor. Any slight lifter noises go quiet after a few drives with the new oil.







Disclaimer: this story may or may not be factual.

[1795]

Originally Posted by 750hp

I like to get every drop out, so after draining the oil cold, I like to start the engine and run it for a while to clear out the oil lines and passages. I find that a good rev after a couple of minutes gets the last of it out of the motor. Any slight lifter noises go quiet after a few drives with the new oil.







Disclaimer: this story may or may not be factual.

Isn't that standard practice fora proper oil drain? :roll eyes: Which oil producer was it that ran that commercial in the 70's in which they would put their oil and a competitor's oil in engines on stands, run them, drain the oil and then run them until they seized. The engine using the oil from the producer of the commercial would aways still be running after the other engine seized.

I agree with the others people who think that the cold engine gave up more oil than the hot one because more oil was in the pan and not still making it's way back to the pan.

Regarding the 2.5 quart difference, I have no idea

[patrickt]

Originally Posted by jhv48

Glad somebody finally brought this up.
...

RodneyM -- not only was it interesting, but I'm actually receiving praise for posting it. Now I feel particularly good about myself.

[undy]

Maybe the 90 weight gear oil you've been using to be able to say "I've a drip free FE!" is hanging under those valve covers, partially solidified on top of that cold engine and not draining down to the oil pan? This caused you to "think" that you needed another half quart.

Either that or, in a panic attack of the nearest Taco Hell being closed, you just lost count...

[rodneym]

Originally Posted by patrickt

RodneyM -- not only was it interesting, but I'm actually receiving praise for posting it. Now I feel particularly good about myself.

If only Chas were here...