If you removed ALL the oil.
And the manual said 56 oz.
And you added 56 oz.
THEN I would file a new line on the
stick and use it.

Did you save the old oil?
You can measure it.

Actually, this is what's confusing. The manual says 56oz w/filter, 48oz wo/filter. All I put in was a 48oz 30w container, and it shows over full.
Manual - PRODUCT SPECIFICATIONS
Gasoline 1.25 Gallons
Capacity and Type: Unleaded and Regular
Oil Type SAE 30 (above 32F)
API-SG-SL): SAE 5W-30 (Below 32°F)
Oil Capacity: W/Filter: 56 oz.
W/O Filter: 48 oz.

Jim - stick with the dipstick reading. Those published oil capacities - while usually close - are based on optimum internal engine cavity dimensions and there will be some variation from engine to engine.
So, yeah - drain a tad to get the engine oil level correct to the dipstick, IMHO

Thanks rcbe, I'll do that.

Be sure the tractor is setting on a very level place when you check the oil. A lot of times it can look level and not be level. I have a little magnetic level I put on the frame when I change or check the oil. I found it amazing how much the reading on the dip stick can change at half a bubble off.

Use what the dip stick reads. Same thing happen to me this weekend! Drained it to full on the dip stick. And all is GOOD! Now on my Vanguard I need 2 quarts and a 1/4, with the filter. I didn't change the filter on the Kohler. So it was 1-3/4's of a quart on a 2 quart stated amount. The Vanguard stated the same amount. Read the dip stick! Ya got to trust something! That's what I'll say in court, if the time comes!

ms

Alright, thanks guys. The dipstick it shall be.

Jim and others: We've all experienced the headaches from overfilling our mower's engines with oil either from oil changes or topping it off.

Here's a simple way I found to help out: I went to the local pet shop and purchased a large sized hypodermic syringe setup - sans the needle.

I then purchased a length of clear aquarium air hose that would fit snugly over the tip of the syringe - about 3 feet if I remember correctly so I had spare hose for later use. I even told the clerk what I was using it for so no questions there...

I cut the hose to about 8" longer than I needed to stick down into the oil fill tube, and then threaded the air hose in the fill area. Using the plunger, you can suction some of the oil out at a time to get to the proper oil fill level on the dip stick.

Not the prettiest method, but it does give you better accuracy instead of pulling the drain plug, refilling. Opps! To much again, etc.

When finished with the oil, just put it back into the unused oil container for later use. No harm done there for the most part. Wipe up your new tool, and put it away for later use. This works for a number of small engines too.

I think my total investment cost was about $3.00 + tax.

Oh, be sure to wipe the oil fill area first before using this method. Just a reminder.

With the need to make seasonal oil changes on my boats, I've tried several devices for extracting oil from the dipstick tube. Most mid-size boats with engines, have them positioned low in the engine room bilge - allowing no room to access the oil-pan drain plug, or for placing a container under. Here's a 5 qt. pump I bought several years ago, which worked great for this purpose.

{{gwi:330552}}

Reading this thread got me thinking that it would work well for extracting excess oil from my tractor. My current sailboat's diesel has an automatic oil changer - so this thing's just collecting dust in the garage anyway.

OTOH, this exercise may be superfluous - since in the past, if I had overfilled the JD's Kohler, I'd simply drain a bit into a container from the engine's dedicated crankcase oil drain cap. ;-)

Just for the heck of it I contacted the Sears tractor tech about this. This is what he said:
"I apologize for the misprint in the owners manual.
The best way to fill your engine with oil is to use the dipstick. Bottles of oil with certain amounts in them are sometimes not correct and the engine can be damaged if the oil level is not checked with the dipstick. I am very glad you checked your oil and didn't trust the 48 ounce bottle.

I would start with most of a quart of oil and top it off with the dip stick. This way you will know you have the correct amount of oil."

I'd like to know what the manual misprint should have said though.

I don't know how to explain this phenomenon, but when I go to my barn to check the oil level in the Wheelhore Kohler engine, the oil on the stick will be all the way up to the top, 4 inches above the fill line. Wipe it off and insert and it shows normal.

Must have something to do with the temperature difference, but it happens every time.

***"4 inches above the fill line. Wipe it off and insert and it shows normal. Must have something to do with the temperature difference, but it happens every time."***
Yes, temperature change creates "partial vacuum" (negative pressure) inside the dipstick tube when the engine cools. While the engine is running, the dipstick tube tube heats up same as other parts near the engine. When you cut the engine off, the oil in the engine becomes still and covers the bottom portion of the dipstick tube. As the dipstick tube cools, the air above the oil inside the tube cools off. As it cools, it "contracts" a bit (becomes denser or "less rarified"). When this happens, a partial vacuum, or "negative pressure" develops inside the tube. At this point, outside "atmospheric pressure" is higher than the pressure inside the dipstick tube. This allows the oil in the crankcase to be PUSHED up into the dipstick tube by the "atmospheric pressure" above the crankcase oil. You can perform a demonstration of this phenomenon on your kitchen counter if you wish. It's clean and only requires a "clear bottle" (glass is best), a common saucer, and hot water. Put some cool water in the saucer. Take your glass bottle or other similar container and warm it by running hot water into it till it is full. Allow this to "stand" for a moment so the bottle is good and warm. Next, empty the water out of the bottle and immediately place the "upside down" bottle into the saucer of cold water so that the open bottle mouth is submerged in the water. As the bottle (and the air inside bottle) cool off, the "barometric pressure" inside the bottle will become lower than the barometric pressure outside the bottle. The higher outside pressure will begin to "push" water into the bottle as "nature abhors a vacuum". If one were to provide a "vent" orifice in the top of the dipstick tube, this phenomenon could not occur. BUT if you provided a vent, it would "slobber oil out" AND be a source of dirt contamination.
It is good that baymee brought up this subject. The "word to the wise" here is. NEVER accept the "first withdrawal reading" of any dipstick (if it fits into a tube) as an accurate, or true, reading! Always wipe the stick clean and take your reading from the second withdrawal of the stick. Dipsticks that drop into a large "tubeless" cavity (no tube end under oil) would be exempt from the phenomenon, but why chance it?

Great explanation. I remember doing that experiment in school, but after 40+ years I forgot.

Mownie, I'm not so sure I would completely buy into this explanation for the case of high dipstick oil level. I have a '97 Maxima that ALWAYS shows an inch or so too high on the dipstick when cold, on first level check. But the there is no dipstick tube, it just fits down into a hole in the block casting so there is no differential cooling between the block (and oil) and any air above the oil level (no tube).

I also noticed that the oil level on the dipstick of my 11HP Tecumseh (MTD tractor)had always shown at least a half inch or more high level, opening up the possibility to your explanation. This motor does have a tube, but no sealing element between the screw down dipstick cap and the top of the oil tube. I found that if I even bumped the tractor a little, it would show a high level first check. But, if I was VERY careful not to jar or move the tractor in any way, checking the level would show it at the correct mark. So in that case just the movement of the oil in the crankcase would obviously slosh it up the dipstick tube.

Without a tight air seal at the dipstick cap in many cases, how can there be a vacuum? I will say that there is an O-ring on the screw down cap of my 23HP Briggs (JD ZTR), but it always checks at the correct level.

How would you explain the above?

In my case it's not from bumping the mower. The barn temperature is significantly cooler than the outside air at any time during the year. It's always stored after use, so the oil is hot and always checked when it is cooled.

Think of the savings not changing the filter! I cannnot count the broken Kohlers in my shop sporting the oem oil filter. A CV20 installed, $1000, new oil filter, $8. Having your tractor when you need it? Well you know the answer.

larso1 asked ***"How would you explain the above?"***
I answer: Larso, I can't explain that in any way regarding the partial vacuum or negative pressure phenomenon, and it certainly would not apply to the Nissan Maxima in your case. But, you are not alone in having a Nissan product to exhibit this same characteristic of "oil level on stick appears higher on the first (or even second) withdrawal". I own a 1990 Nissan D21 pick up with the 2.4 engine (KA24E) that will show a higher level on the stick upon the first "pull out" of the dipstick, or sometimes even the second pull in cold weather. My 2.4 engine DOES have a long, curved dipstick tube, BUT....it terminates at the engine block near the oil pan flange. The tube is mounted into the block but does not protrude inside the crankcase, and certainly does not reach far enough to be "into the oil". Sometimes, when I first pull the dipstick (first time pulled since the engine was last shut off), the oil on the stick appears to completely cover the surfaces of the stick and it would seem that the oil is "over full". Other times (on the first pull since shut off), the oil just appears along one side or edge of the stick, above the actual oil level mark. Wiping the stick and putting it in for a second or third withdrawal will produce a correct oil level "reading". I think that another "phenomenon" is responsible for "what we think we see" in the case of "our Nissans" (but probably not limited to only Nissans). After you "posed" the above question, I tried to think of "some other process" that could produce the "high oil level" in the absence of a submerged tube end, or an "air tight" upper dipstick seal (cap on stick). I can only surmise that what takes place in these configurations is due to the "innate cohesion" of the lube oil, PLUS, the "close confines" offered by the juncture of the dipstick and the dipstick hole in the crankcase. Here's what I think happens: When the engine is running, lube oil is transported throughout the oil gallery to the nether reaches of the engine, as well as being thrown off the crankshaft. The result is a lot of oil on the inside surfaces of the engine that will eventually drain back to the sump (unless a "pool" forms somewhere). The "drain back" process will require a relatively long time to transport the "lingering traces" of lube oil back to the sump under the influence of gravity. The "majority" of the oil mass returns in a matter of seconds, to be recirculated. The "lingering traces" of oil will continue to drain back for days or weeks, but with "diminishing returns". Oil has a "property" (as do ALL liquids) known as "cohesion". Cohesion (from "cohere") is defined as the ability to "stick together". Cohesion is greater in thick, viscous liquids than in thin, "runny" liquids. The natural tendency for liquids to "exhibit cohesive activity" can be enhanced by placing the liquids into a "close quarters" setting. In "close quarters" or confined spaces, the innate cohesiveness of a liquid will allow greater amounts of said liquid to "accumulate" or "cling together" in contact with the narrow, or "close confines" of the adjacent, impervious, surfaces. Cohesion and adhesion are closely related in this respect. Anyhow, I think that the "lingering traces" of lube oil track down the inside surfaces of the engine, in both sheets, and tiny rivulets, of oil. As the oil runs down the inside walls of the crankcase at the point where the dipstick blade emerges from the block, the "narrow confines" or "close quarters" of the blade inside the hole, present an opportunity for the draining oil to both cohere together and adhere to the inside of the hole in the block and the dipstick. This "pocket of sequestered oil" is enough to coat the lower portion of the dipstick as the dipstick is withdrawn. I can imagine that the pocket of oil is able to extend downward a bit onto the dipstick below the actual lower edge of the hole once the oil cools and both cohesion and adhesion increase. The amount of oil in the pocket would be enough to completely (or at least partially in some instances) coat the withdrawing dipstick blade, giving the "first impression" that the crankcase is "way over filled". Because the oil that first "founded" the pocket, would track down the dipstick blade and into the sump oil mass (remember, the end of the blade IS SUBMERGED) the during the drain back process, the entire length of blade below the oil pocket would already be "primed" with a film of oil, thereby making it even easier for the oil in the pocket to completely coat both sides of the blade on first withdrawal. After wiping the stick, a second insertion and withdrawal might still show a smear or streak of oil on the stick ABOVE the actual oil level mark. Additional insertions and withdrawals will finally "remove" the oil pocket from the hole and you will be able to observe just the actual oil level on the stick. ALL THE MORE REASONS to disregard the first withdrawal "reading" of ANY dipstick. I know the old adage about "checking the oil before you crank the engine" will show the highest possible, and accurate, oil level. But you better not pull and read "JUST ONCE"! You better "pull & read" several times to be sure you are "reading" only the level of oil in the sump and not the "sequestered pocket" of oil.
We all need a "minimum" of 50 quotation marks daily. You just got yours. :^)

Theory # 232 - engine block internal temps spike just after engine shutdown. Could there be enuff temporary air/gas expansion in it's crankcase to push thet oil level up a tad in the chk tube and then pull back as engine cools leaving a "high" mark on the dipstick?

**"Theory # 232 - engine block internal temps spike just after engine shutdown. Could there be enuff temporary air/gas expansion in it's crankcase to push thet oil level up a tad in the chk tube and then pull back as engine cools leaving a "high" mark on the dipstick?"***
.................................................
If you mean: The high mark of "the oil that was pushed into the tube" would remain in that place until the next time the oil was checked, thereby causing the oil level to seem high. Answer: NO, for a couple of reasons (at least a couple). The oil CANNOT be pushed into the dipstick tube simply by "air/gas expansion" in the crankcase due to the internal spike of temperature immediately after the engine is shut down, because......the crankcase IS NOT a sealed vessel (in regard to holding a "pressure head"). A typical crankcase has at least 2 avenues for relieving any pressure that might develop as a result of "thermal expansion" from an after-operation heat spike.(1) The crankcase vent or breather, which is there purposely to relieve, vent, or otherwise "equalize" the crankcase pressure to atmosheric pressure. (2) The clearance between the piston, rings, and cylinder wall IS NOT, a complete seal or closure. Some "blow-by gasses" from combustion enter the crankcase on every compression stroke and power stroke. The fact that they "blow by" or "past" the piston & rings is the reason for the term "Blow-by". Blow-by is the primary reason for needing a crankcase breather or vent. Just as blow-by enters the crankcase in the piston & rings area during operation, any pressure that develops in the crankcase from thermal expansion would vent out by escaping past the piston & rings, even if there was no crankcase breather in place.
If a pressure could form (and be contained) inside the crankcase after engine shut down, the resultant pressure could indeed "push" the oil upward into the dipstick tube area (only applies to tubes submerged in oil), BUT....the oil would only be able to rise in the tube until the pressure inside the tube, became equal to the pressure inside the crankcase (because the dipstick tube is "sealed" by the cap on the end of tube.....the tube itself is a "pressure vessel".) Later, after the engine has cooled off completely, the pressure inside the tube would push the oil out of the tube. In this scenario, the "greater volume of space" in the crankcase, versus the "smaller volume of space" in the dipstick tube, would cause a greater "negative pressure" to form in the crankcase than in the dipstick tube. The greater negative pressure in the crankcase would then "pull" the oil out of the dipstick tube a bit, causing the oil level to be lower. The idea that the oil might remain at the "highest level reached" cannot happen because, in the absence of any "confining" or close quarters, to support "cohesive accumulation", the oil would simply obey gravity, and run down the stick into the oil mass. The dipstick tubes I have seen, that actually submerge into the lube oil mass, have too large a diameter to lend to the cohesion effect. While the engine is running, a certain volume of oil is missing from the oil in the crankcase. This "missing oil" causes the oil level in the crankcase to fall below the bottom lip of the dipstick tube. The "missing oil" is oil that has been slung or splashed onto surfaces inside the engine, but has not yet drained back to the sump. After the engine stops, the "missing oil" can finally get back to the sump. Unless it gets "retained" or captured, by a convenient, pocket of cohesion somewhere.

Yah mownie, you almost need a boroscope to see what's going on in the crankcase and how the casting geometry inside could have an affect...could be different causes of high oil level readings. You kind of touched on a theory of mine, being the "wicking effect" (note quotations) of liquids between two very close surfaces, and subsequent cohesion of the cooled viscous oil on the one side. It seems that on the Maxima that it's usually only on the "back" side of the stick that reads high....takes several dip/wipe sequences to get it reading right.

larso, your "wicking effect" is but one "variation" of liquid behavior due to "cohesion". "Capillary action" and "osmosis" are a couple of other processes that come to mind. (I just love my "quotation mark key", I use it "all the time".)
I fear that some readers will need a "BOREscope" to get through my "boring" discourses. ":^)"

Well, after all that--i have decided that the engine oil is splashed up the dip-stick tube, so you'd better double-stick it every time you go to start the engine! I guess my aged brain is too old to decipher the fore-going explanations, so, how the oil gets up high on the dipstick from running it won't be a problem for me--i just double-stick it every time, and all is well in my barn!

Typically when they say for example 32oz. They mean with the filter replacement AND letting it drain for a Loooong time. On a typical automobile, when you drain the oil and it starts dripping (after about 10 min) If you let it drip for 10 more hours, you will typically get another 8oz out of it. It all depends how much time you have and how good a job you want to do. Generally speaking, letting it drain for 30 min is fine. Its kind of like a ketchup bottle, you never really get all of it out!

***"Its kind of like a ketchup bottle, you never really get all of it out!"***
How true! Reminded me of back when I was starting a new job back in late 1970. I had just gotten the job and it was my first opportunity to be working in the "heavy truck" area of the automotive mechanic world. The job was in fleet maintenance. The "fleet" consisted of just about everything from cars all the way up to Cummins and Detroit Diesel engines in the big tractors. The shop manager/foreman had a strict policy about "draining the oil". His rule was "Never try to drain the oil out of a cold engine." This man was a stickler for being "on top of" every vehicle in the fleet in regard to scheduled maintenance. He read every driver report sheet (driver had to turn in report every day) and plotted when a vehicle would "be due" a service. He was so good at scheduling and being in touch, he would keep an eye on the fuel island or the "inbound lane" so he could "catch" an inbound unit that was "due" before it had a chance to cool off. Sometimes we would unhook the tractor right where it sat (and have our "hostler" move the trailer) so we could get it into the shop and drain the hot oil. We also had to work "half a day" on Saturday doing "oil changes" that arrived too late on Friday. The shop manager always showed up at work an hour ahead of the rest of us on Saturday. The first thing he did was tour the truck parking lot and crank the engine on every vehicle that would receive an oil change that morning. He would crank 'em up and set the throttle lock at 1,000 RPM and leave 'em running. They would run at 1,000 RPM until the servicing person came for it. His opinion was, " If you crank up a cold engine and drain the oil before the engine reaches normal operating temperature, you will leave a couple of quarts of oil up in the engine (on the big diesels, 42 to 48 quarts capacity). He said once you crank a cold engine, you better get it hot before you dump the oil or "you're just wastin' your time". He also remarked often that you could always "spot" a mechanic that "overhauled Cummins' engines". He said their shirts all had "black polka dots" that won't come out in the wash. He said "them old Cummins 220's will drip oil for 6 months after you take the pan off". I can close my eyes and still hear his words.

"If you crank up a cold engine and drain the oil before the engine reaches normal operating temperature, you will leave a couple of quarts of oil up in the engine..."

Probably best to apply an external electric heater to the sump (magnetic attachment type or?) prior to draining a cold engine. At least then you won't have all that oil on the top end, hot or cold.

[quote]"If you crank up a cold engine and drain the oil before the engine reaches normal operating temperature, you will leave a couple of quarts of oil up in the engine..."

Probably best to apply an external electric heater to the sump (magnetic attachment type or?) prior to draining a cold engine. At least then you won't have all that oil on the top end, hot or cold.[/quote]

An electric heater is not good enough. The idea of bringing an engine up to operating temperature before draining the oil is not only to get the oil warm so it drains easily, but also to stir up any contaminants, sludge, moisture, etc., that may have settled to the bottom of the sump and get them mixed up with the oil so that they will also come out of the engine when you drain the oil.

Before my original statement gets buried too far back in the posts: The original content of the post explained that the oil capacity of the engines in the topic was between 42 and 48 quarts. You certainly aren't going to leave 2 quarts "up in the engine" on a 5 quart engine. External electric heater........may be good for helping to keep the oil warm for cold weather starting. Would not be practical as a substitute for actually heating the entire engine assembly in prep for oil change, for all the reasons in the above post. All the diesel engines in that fleet were fitted with electric engine block heaters. The truck/trailer parking area had electric outlets on panels situated on concrete "islands" that served two tractors and trailers each. These electric panels provided 120 VAC for the engine block heaters and separate outlets provided 240 VAC for running the trailer "Thermo King" reefer units on "stand by power" as we called. We never had a problem starting an engine in cold weather except when a block heater might fail. Anyhow, we would sometimes have to service 4 or 5 tractors on some Saturday mornings. The boss coming in and warming up the engines was just the right technique for making sure we got a "good drain". This shop manager was very consciencious about how the fleet was maintained. He was a manager AFTER he had a career as a mechanic. You found more of those credentials back then than now.

Mownie said: He also remarked often that you could always "spot" a mechanic that "overhauled Cummins' engines". He said their shirts all had "black polka dots" that won't come out in the wash.

I worked for two years in a pit servicing touring buses. I never had that problem. All my T shirts were black. I learned that lesson on the first day.

"All my T shirts were black. I learned that lesson on the first day."

Yah, makes you kind of wonder about those Cummins mechanics, don't it?

" The idea of bringing an engine up to operating temperature before draining the oil is not only to get the oil warm so it drains easily, but also to stir up any contaminants, sludge, moisture, etc., that may have settled to the bottom of the sump and get them mixed up with the oil so that they will also come out of the engine when you drain the oil."

Contaminants and moisture should already be entrained in the oil, shouldn't it? That's what that additive package is for in modern oils. So I don't see how pumping it back up into the motor could help any. Sludge is another thing, and again I doubt you'll get much more of that by running the motor. The oil pump isn't going to pull it off the bottom of the pan (at least you'll hope not) and you'll pretty much have to remove the pan to clean it out....or run some solvent thru your motor first. It's just my opinion, but you'll have to show me lab test results to the contrary to change it.

***"Contaminants and moisture should already be entrained in the oil, shouldn't it?"***
To a degree, yes. Contaminants will be entrained during operation of the engine and circulation of the lube oil. Moisture is a "transient" contaminant with a short life span. Even though the H2O is "transient", some of the moisture will re-combine with other components of combustion even while still in the combustion chamber (prior to being "blown-by". These compounds are NOT TRANSIENT and will remain in solution in the oil where they will become acid and attack the oil and engine surfaces. Actual moisture is introduced to the crankcase lube oil in 2 ways. Most of the moisture gets into the crankcase as a component in the blow-by gasses during cold start up. The water is one by product of the combustion process. The other, and "lesser" way is from the natural humidity of the inducted air. The "inducted air" moisture gets to the crankcase lube oil as a component of blow-by, but also in the air that is "fed" to the engine to ventilate the crankcase (PCV system). The moisture is only able to mix with the lube oil when the engine surfaces and the oil mass are cold. After the engine and oil mass heat up, most of the moisture is "driven out" of the oil. The evaporated moisture will be drawn out of the crankcase by the PCV system and be sent back through the induction system again where it can be expelled out the exhaust. High temps are the determining factor in keeping the moisture "out of solution" or "out of emulsion" in the lube oil. Even though the contaminants are in suspension during operation of the engine, as soon as the engine stops and the majority of the oil drains to the sump, STRATIFICATION of the liquid begins to happen. During stratification, the heavy, solid particles settle to the bottom of the sump first. After that, the liquid components of the oil begin to separate into distinct layers, or "strata", according to the specific gravity of each component of the blend. The longer the time at rest, the more complete will be the settling process. The "more used" or older the oil is, the faster the solids will settle too.
***"Sludge is another thing, and again I doubt you'll get much more of that by running the motor. The oil pump isn't going to pull it off the bottom of the pan (at least you'll hope not) and you'll pretty much have to remove the pan to clean it out....or run some solvent thru your motor first."***
The sludge is formed ONLY WHEN the oil in the crankcase has remained in service for too long. Oil that has been in service too long, has lost most of its additive package to heat and contamination from blow-by. When good oil is fresh or new, hardly any settling or stratification occurs (unless the engine is 'off" for a very long time). During the time after fresh new oil is put in an engine, practically everything the oil has "picked up", remains in suspension. If the engine has always had "timely" oil changes, and has always been run long enough after cold starts to drive off moisture, there will be very little (if any) "sludge" in the pan or elsewhere in the engine. As the oil ages and degrades, stratification begins to occur during periods the engine is not running. During this "phase" of the oil's life cycle, any particles that settle (sludge keystones) will be "scrubbed" and swirled back into suspension by the detergent additives in the oil's formula. As these additives grow weaker and thinner with continued use of oil that is degraded (and really no longer fit for service), the "sludge" that forms during "off periods", is more difficult to "remix" in subsequent run periods. So, consider the oil additives as though they are "continuous solvents" that scrub and clean the engine whenever the engine is running. Oil change is good. Fresh oil is good. Vibrant additive package, good.
In my opinion.....there is a definite benefit to changing the oil WHILE STILL HOT from a long run time. The "perfect time" to change the oil would be at the end of a 12 hour period of use, immediately after the engine was turned off. Obviously, this is not practcal, so we must try to do the next best thing.

I think mownie knows a thing or two about oil changes. Well said mownie .

mownie, very good explanation.

larso1 said, "you'll have to show me lab test results"
I can't show you lab test. I can only tell you from my experience as an auto mechanic for 20+ years.
Back in the 50's (before detergent oils, before full flow oil filters, and before Positive Crankcase Ventilation systems) when I was first taught about changing the oil when hot, I had a 1951 Chevy. After changing the oil when hot at regular intervals a few times, I pulled the valve cover to adjust the valves. Well, the inside of that valve cover and the top of the head and the area around the valves was "clean enough to eat off of." This is what made me a believer of changing the oil when hot. Over the years, I have seen more than a few engines built up with sludge. Plugged oil pump screens, plugged oil passages in the block and in the crankshaft, lifter valleys with so much sludge the drain back holes were plugged and you couldn't tell where the lifters were. This only served to reinforce my belief in changing the oil when hot.

If you want a practical demonstration, drian the oil fro m your engine when hot and leave it in the drain pan for a few days, then empty the drain pan. Notice how much sludge is left in the drain pan.

Quote: If you want a practical demonstration, drian the oil fro m your engine when hot and leave it in the drain pan for a few days, then empty the drain pan. Notice how much sludge is left in the drain pan. Quote.

I can attest to the sludge comment. I burned thousands of gallons of waste motor oil in our company boiler and there is always a few inches of sludge at the bottom of every 55 gallon drum in storage.

***"I burned thousands of gallons of waste motor oil in our company boiler and there is always a few inches of sludge at the bottom of every 55 gallon drum in storage."***
As far as I'm concerned, the above quote could have been signed, "Bayee Laboratories Research, Baymee, PHD". :^)