Thats not going to flush anything out. Almost all of the oil is just going to sit in the head, unless you put a lot in to make it drain to the lifter valley. And still its not gonna be flushing anything out. And then what about the drivers side? How about the bearings? Dont waste your oil.


Change it when its hot.

 

I've got one and it's great! It makes the oil flow out a little slower, but I always let it drain at least a half hour anyways, so it all equals out.

This setup is great because it makes taking oil analysis samples much easier, since the flow isn't so strong.

PS- you should always drain the oil hot, or you won't get all the contaminents out.

 

you want the oil to be warm so it flows good... but you don't want it to scald you... after the temperature changes reads below 160 is usually good i like to wait till i can hold my bare hand against the oil pan for a count of 4 or 5 seconds without burning myself

and since my car took 5.5 quarts i would buy 6... and when the old stuff drained i would pour thru half a quart of new stuff to push all the settiment crap out (there really wasn't any) but it made me feel better

 

If you're worried about hot oil burning you, just buy some good work gloves. That's what I use. I mostly need them for when I remove the oil filter though.

 

Would you mind elaborating?

 

Draining it hot means the contaminents remain in suspension, draining it cold could mean more oil is left behind, since it doesn't flow as well, it'll be much thicker.

Another reason for changing it hot is so that there is still a good film of oil on the parts when you restart the engine, since you'll have a momentary lag of oil flow as the oil gets refilled in the passage above the oil filter.

 

But if you drain cold, the hot oil still drains down from the engine to the pan. I can only see draining the oil cold as leaving a very slight extra amount of oil in the oil pan.

Are you saying the contaminants sink to the bottom of the oil pan and stick to it, therefore not coming out of the drain hole?

 

That's the way I understand it, that some of the contaminents may settle to the bottom of the oil, and not all of them come out when you drain it cold.

 

I don't know why the old rules stick around so long. Forty years ago, when oils did not include detergent dispersant additives, the oil was changed hot because it was thought the contaminents would still be in suspension and be removed more readily. Now that modern oils have incredible dispersant qualities, whatever is in the oil stays in the oil, hot or cold. It is not like there are any lumps in the oil or anything......
Change it hot or cold, whichever you prefer or have time for. It will make no difference.
At least one quarter quart of oil remains in the engine, no matter how long you drain it for. There are lots of little pockets, especially in the heads, that retain oil. Pull the plug, change the filter, install the plug. Done.
There is no way "moisture" is going to migrate into an open drain plug hole. I have never heard that one, and I have heard a bunch. Moisture is a concern when a head gasket blows. Wait for that to happen, and it will, on these engines. Then you can be concerned about "moisture".
It is just an oil change, not rocket science. There are lots of other complicated and difficult repairs to be concerned about on these cars. Don't make an oil change one of them.

 

Hey man it's no fun if we can't overanalyse it!

Condensation is what I am referring to. Condensation in the oil pan caused by the difference in temps from outside to inside a hot oil pan. Maybe it doesn't happen... I dunno.

I think I'm gonna stick with draining it cold b/c I won't have to wait so long for it to all drain from the block.

Patman's logic makes sense, but I think either what the above post says is true, or it just ain't enough to be concerned with. Come to think of it, shouldn't the filter catch anything big enough to actually seperate from the oil?

I think we are officially beating this to death LOL

PS The last time I changed oil in an old farm truck we have, I found rust in the dipstick tube with some gunky, clunky oil on the bottom of the stick. I sprayed carb cleaner down the tube then followed it up with brake parts cleaner (evaporates, 'leaves no residue'). It ran right out the drain plug. Wouldn't try that on my car, but this ol' beater often gets strange experiments done on it

FWIW the Shell oil I put in it had the consistency of 2% milk. It was so thin... could be massive blowby, but I won't even put that stuff in beaters anymore it freaked me out so much.

 

I guess I'm being overly cautious, since there honestly isn't a ton of contamination in your oil anyways, especially if you're changing it every 3k anyways. But you might as well change the oil when it's hot just to be sure. I'm almost positive that you'll get more oil out of there when it's hot, maybe only 1/8th of a quart more, but every little bit counts.

 

I honestly think the difference would come down to the thicker layer of oil staying on the bottom of the pan when it's cold versus hot. I think that is so, so small. But, when I think of draining the car after it's sat overnight and so much more oil has been able to drain from the block, I think the additional oil from the block may be more than is left behind in the pan b/c it's cold. So, thinking about it more, I believe at this point I net out more drainage when it's cold IF it's been sitting a long while.

I've made up my mind. I feel better draining when it's been sitting for a long time.

To each his own I reckon

 

Why not just do it the way I do it sometimes, I drain the oil hot, but then leave the plug out for two hours! By that point in time, pretty much everything that's going to drip down into the pan, will have done so.

When I'm switching brands of oil, sometimes I'll do a quick flush, and run 3 quarts of the new oil in the engine, run it at idle for one or two minutes, then drain it out and pour in 5.25 fresh quarts. That way when I'm done, only maybe 1% of the previous type of oil was in there. Sure, it's super ridiculous, but it gives me a better idea of how the oil will perform on it's own since I do used oil analysis on each interval. If it's still mixed in with 5-10% of a different brand of oil (esp. when I change viscosities) then it's not going to give me a total picture of how the oil is performing. For instance, later next week I'm switching to a thicker oil. I want to see how it's viscosity ends up at the end of the interval, but if 10% of the thinner oil is still mixed in with it, the oil sample will look as if the oil has thinned out more than it really did.

 

Yeah I fully agree. I'm not quite that obsessed yet, but I do this with the farm truck I referenced sometimes. It's so old and the oil gets contaminated pretty bad. One time I got water all in the engine and used some old oil from my car to flush it out with. I think that's where all the rust in the dipstick tube came from LOL