Oil Change - thought - Question
 

I never paid much attention to oil changes before, I just did them. There is however alot of discussion on this board about oil changes and that caused me to ponder the following.

If you run your motor until it is hot, then oil is distributed everywhere in the engine. When it has not be running (lets say overnight) it would seem more oil has settled into the pan and therefore by doing it cold more oil would drain (most likley slower).

In my case I thought about doing the first drain in the late afternoon, pull the oil filter, slide the cover back on and then in the morning do a second drain for whats left. Being I don't need ramps and can just reach under it, no big deal.

Am I missing something?

Don

I don't know why you are dividing this into two parts...
Get the engine hot in the evening...do what you said above, leave it overnight, put the plug and oil in in the morning... drive off...

Because we get high winds here at night and the oil drips will spray everywhere, seriously..lol

I drain tractors which are more than two feet off the ground on the edge of an open field .. so I know what you mean about blowing oil..
However, it would be pretty easy to block a funnel up against the bottom of the pan...... to get the benefits of the combo which you described...

Or, in the alternative, those nice brass spring loaded drain cocks are made so you can put a hose on them which reaches to your pan...

Yes indeed more oil is at the bottom of the pan when cold, but that oil will be sticking to the sides of everything when it is cold and will not come out. When the oil is cold the contaminants are not as thoroughly mixed with the oil, thus they stay stuck to the sides of the pan rather than coming out with the hot oil.

Follow leathermangs suggestions and you will be doing much more thorough oil changes.

Good luck,
Change oil hot and change oil often.

ANd don't forget to drain the engine oil cooler if yu want to get the most of the old oil out.

I always start the oil change in the afternoon or evening and let it drain overnight. You are right, sometimes the oil blows around, but its just drops, not much volume. Put a block under the catch pan so it is close the the drain hole and put some newspaper under the car to catch the oil that misses the pan.

P E H

Is it worth the risk having someone start the car without oil in the engine? Are you the only one with the key? What if you really need the car that night, it would be a drag to have to fill up with oil before being able to drive off. Change your oil and filter often seems to be the best plan.

BTW, could someone tell me why MB recommends removing the filter before draining through the pan on the 300D. Is this also recommended for my 450SL?

When I take the oil filter out it drips old oil back
in the oil filter housing, so if there is already
new oil in the the crankcase it will be mixed
with what drips from the old filter. I can't
imagine it really matters if you take the oil
filter out while the drain plug is removed,
and give it a few more minutes to drain.
A word about oil coolers-I've read that the
threads can be easily stripped since the oil
cooler is made of a soft metal. I wonder also
that the empty cooler will take time to fill up...
does that mean the engine will be w/o oil
pressure for that time? I think similiar benefits
to an oil cooler drain can be acheived with
frequent oil changes.
Mark 82'300Sd 280k

Mark,

You should pull the plug to drain the oilpan, then immediately pull out the oil filter. Allow everything to drain as long as possible. That is because you want to let everything up in the oil filter area and other nooks and crannies to thoroughly drain, preferably overnight.

As far as a problem filling the oil cooler goes, there is an adequate coating of oil trapped at the crankshaft journals to prevent any problems during this oil priming period.

Have a great day,
Change oil hot and change oil often.

Larry said something that clicked.

I am going to guess the reason for changing the oil when it is hot, is not to help with the draining, but to put a coat of oil on all the parts to provide lubrication when re-started. There is that period that air needs to be replaced by oil.

For myself, I am going to drop any plans of long term oil draining and just do it as I have always done. Drive it until everything is at operating temp, drain it, pull the filter, at the last few drops (10 mins or so) plug it, new filter and add the oil.

On adding oil, on this motor, for my first change, I poured one gallon in the oil filter housing, 1/2 without the filter, the 1/2 with it. The other gallon through the oil cap.

Next time I will add 1 gallon through the cap, 1/2 gallon into the filter housing before I put the filter in and the last 1/2 gallon after the filter is in.

If I want the oil any cleaner than this, I am going to add an additional by-pass oil filtration system.

MB did away with drain plugs for the oil coolers along time ago. I owned an '80 SD that didn't have one and neither does my TD.