question on changing motor oil

[GYPSY400]

The idea is to drain as much old dirty oil out before refilling and installing a new filter. Why on earth would you

run the motor first and sling the old

dirty stuff back onto motor parts and

fill the filter? The motor should sit for

at least an hour if it's been run.. so

the filter will drain out and save a lot

of mess when removing it. It's gonna

be 23+C tomorrow... no need to

warm it up.

 

The purpose of warming the engine

up before draining the oil is so:

1) the oil is warm and drains faster

2) the oil picks up the "sludge" and

"sediments" and gets it out of the

engine. Oil is designed to collect and

suspend the dirt within it.

By draining the oil cold, you are

basically leaving the dirt inside the

engine ( especially the metallic

particles)

I always drain oil when the engine is

at operating temperature, always

have, always will.

 

Also, oil filters have check valves built into them so they Don't "drain out".. This prevents the engine from dry starts.. So once it has run once

the oil stays in the filter.

[irishfield]

Also, oil filters have check valves built into them so they Don't "drain out".. This prevents the engine from dry starts.. So once it has run once

the oil stays in the filter.

 

Cut one open sometime and reassure yourself of that... Some do.. some don't.. and what most think is a check valve is actually a BYPASS valve.. just in case the filter ever clogs solid. Upright mounted filters on Mercs, or at least the ones I've worked on, do not and they are designed to drain (and why Merc manuals tell you to let the motor sit for one hour before removing filter).

 

Have you ever cut a filter open... stretched all them pleats out and run your fingers thru it?? ... if not you're missing the most important part of the oil change!

 

Also if warming the oil up would "pick up sludge and sediment".. there wouldn't be sludge and sediment as it would already be in the filter from normal engine running.

Edited October 8, 2011 by irishfield

[GYPSY400]

Cut one open sometime and reassure yourself of that... Some do.. some don't. Upright mounted filters on

Mercs, or at least the ones I've

worked on, do not and they are

designed to drain (and why Merc

manuals tell you to let the motor sit

for one hour before removing filter).

 

Have you ever cut a filter open...

stretched all them pleats out and run

your fingers thru it?? ... if not you're

missing the most important part of the

oil change!

 

Well I won't argue that point, if that's what the manual says, then I would follow the manual.. I'm a licensed Diesel mechanic so I'm not too educated on the specifics of marine 4 strokes.

I would still drain the oil hot though! Just let it drain for an hour!!

[GYPSY400]

And by Sludge and sediment, what I'm referring to is all the dirt within the oil that is too small for the filter to catch.. Warm oil picks it up and carries it out. Cold oil - the sludge is sitting on the bottom of the oil pan.

 

But as I said before, if the manual has a specific procedure for changing oil,

the by all means do as they say! An engine is an engine, but they are all designed a little different.

And I agree with filters having a By-pass.. Most good filters have this feature.

I may have been incorrect in saying the "filter" has the check valve, when it may be the engine itself having the check valve to hold the oil in the filter.. This feature is common on engines with filters orientated horizontally to prevent the oil from draining back all the way to the pan.

Edited October 8, 2011 by GYPSY400

[Tybo]

A half clogged filter,filters better then a new one.

 

Wayne: Sometimes I like to put 600 volts to them too.

 

So I guess it's an engine in a electric car.

Edited October 8, 2011 by Tybo

[Billy Bob]

I have never worked on a 4 stroke outboard so my experience there is NADA...but have never ever changed oil on a vehicle that I haven't run to operating temps first......that's the way I was taught back in the '70's...hot/warm oil flows better and carries out sludge better that way.

[Billy Bob]

Dont listen to the Billy Bob guy.He needs to catch some fish himself instead of taking pictures of his friends fish, and posting them as his

 

Actually, I purchase those photos on the internet.... ...lot cheaper then actually going fishing....

[mercman]

Actually, I purchase those photos on the internet.... ...lot cheaper then actually going fishing....

 

Thats what i figured Anything to save a buck.

 

I have always ran a quart of new oil through the motor on my cars, before replaceing the drain plug. I may do the same with my outboard.Its a bit of waste, i know, but i feel it removes alot of the so called sludge from the oil pan.

[Fisherman]

If you ran a good synthetic like Amsoil with a premium filter, you wouldn't get any sludge. I pulled the oilpan off my old 78 Rabbit at 12 years and 240 thousand, no sludge. No sludge under the valve cover either. And by premium filter, I don't mean the ones that start with the letter F and sound like a dodge truck.

[Tybo]

Are engines at work get roll ins done about ones a year.There is very little and talking little sludge in the oil pan.This is because the

oil now days is very clean.

Also there is same amount of sludge in the pan hot or cold. The hot thing is to get you to change the oil as soon as it comes in.So the company

can get more done.Good ploy.

Dropping oil pans for 30 years I have seen the changes in oil first hand.

If the maintenance is done a the proper schedule the viscosity of the oil is still high, holding most contamination suspended.

[wallyboss]

Got this from somebody and never again will have a oily mess after changing my motor oil on my 75hp Merc 4 stroke.

 

Go to the store

 

Get 1/4 inch drain plug, one end threaded other end open, about $1.25 at Princess Auto

 

Get 2 or 3 feet of 1/4 tubing also about $5 at Princess auto

 

Get a gear clamp, about 25 cents anywhere

 

assemble

 

Trim motor up and to the side

 

Remove drain plug

 

Screw in new assembly

 

Drain

 

Works like a charm and zero mess

[Jen]

I am curious as to why no one here has mentioned the use of an oil pump to remove the oil before you actually take off the drain plug, it certainly saves the mess!