GYPSY400 Posted October 8, 2011 Report Share Posted October 8, 2011 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. Link to comment Share on other sites More sharing options...
irishfield Posted October 8, 2011 Report Share Posted October 8, 2011 (edited) 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 Link to comment Share on other sites More sharing options...
GYPSY400 Posted October 8, 2011 Report Share Posted October 8, 2011 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!! Link to comment Share on other sites More sharing options...
GYPSY400 Posted October 8, 2011 Report Share Posted October 8, 2011 (edited) 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 Link to comment Share on other sites More sharing options...
Tybo Posted October 8, 2011 Report Share Posted October 8, 2011 (edited) 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 Link to comment Share on other sites More sharing options...
Billy Bob Posted October 8, 2011 Report Share Posted October 8, 2011 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. Link to comment Share on other sites More sharing options...
Billy Bob Posted October 8, 2011 Report Share Posted October 8, 2011 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.... Link to comment Share on other sites More sharing options...
mercman Posted October 8, 2011 Author Report Share Posted October 8, 2011 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. Link to comment Share on other sites More sharing options...
Fisherman Posted October 8, 2011 Report Share Posted October 8, 2011 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. Link to comment Share on other sites More sharing options...
Tybo Posted October 8, 2011 Report Share Posted October 8, 2011 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. Link to comment Share on other sites More sharing options...
wallyboss Posted October 9, 2011 Report Share Posted October 9, 2011 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 Link to comment Share on other sites More sharing options...
Jen Posted October 11, 2011 Report Share Posted October 11, 2011 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! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now