Warm motor? before oil change?

[sundarpn]

I have beeing changing the motor oil on my cars for a while now.

I always wonder if one needs to warm up the motor for a few minutes before draining.

I figure if the motor has been off for a few hours, almost all oil has made it's way to the pan. So drainig when cold will get most of the old oil out?

[TRD VVTi]

It's better when the engine is hot that way all of the contaminates are in suspension in the oil.

That's my opinion.

I always let the oil drain while I do other things like check the other fluids, check/rotate the tires, fill the oil filter with oil, etc... I do that so as much of the old oil gets out as possible.

Either way will work fine.

[onsknht]

Should do it when it's hot, everything is mixed up and not stuck to the bottom of the pan... I see your point entirely about getting all the used oil out, there will always be a teaspoon or two... So I pull the plug after I park the car for the night and then finish the oil change the next morning.

[gdanaher]

If you have a car with a few miles on it and want to get more crud out when you change oil, add a pint of atf the last fifty miles or so before draining. ATF is very detergent and will clean the gupe out of the engine and let it drain out. If that doesn't float your boat, you can also drain the oil. Let the engine cool off. Put a quart of ATF in the engine and let it idle with that for a couple minutes and then drain it out and change the filter. The red atf will come out pretty black if there is a lot of carbon in the engine.

[dbkevindb]

take the filter out after the oil is completed out or when the oil is draining ?

[gdanaher]

Originally Posted by dbkevindb

take the filter out after the oil is completed out or when the oil is draining ?

Take your pick. If you are draining all the oil out then the filter is finished doing its thing and is getting replaced anyway, right? It makes no matter which gets done first.

Drain the oil, replace the filter, check the drain plug torque, add oil, start car and look for leaks.

[onsknht]

Originally Posted by dbkevindb

take the filter out after the oil is completed out or when the oil is draining ?

I have a habit of waiting until all the oil is drained... Earlier Toyotas would drain the filter while the crancase drained and it would come off clean, later models appear to keep the oil in them... This sucks because spinning the filter off usually causes oil to gush out getting on frame pieces etc. The oil won't harm anything, but it sucks to have oil dripping for weeks after the oil change.

[bluemoose]

I do it the same way I wash my hair.... like the shampoo bottle directions, rinse and repeat.

I always to a double back-to-back oil-change just to make sure all the bad stuff get purged from the engine/oil pan.

[Camread]

before an oil change, put a can of engine flush in, run it for bout 5 mins and drain da oil.

[TRD VVTi]

Originally Posted by bluemoose

I do it the same way I wash my hair.... like the shampoo bottle directions, rinse and repeat.

I always to a double back-to-back oil-change just to make sure all the bad stuff get purged from the engine/oil pan.

That's insane. I can't believe that someone does that.

I would never add oil flush to an engine or ATF. Unless of course the engine is basically junk anyways...

[gdanaher]

Originally Posted by TRD VVTi

I would never add oil flush to an engine or ATF. Unless of course the engine is basically junk anyways...

TRD, this is actually an old mechanics trick to slowly desludge a nasty engine. Say you have a client whose engine is in fact gunked beyond imagination. If you try to clean it too well you run the risk of clogging passages and destroying the engine. You chance the oil, add a pint of atf to the oil and proceed to change the oil filter every 300 miles and top off with a little oil and atf. It will clean the engine. Same goes for flushing a dirty engine with atf for 2 minutes and then draining and changing the filter. Don't need to do it with a low mileage well maintained engine, but not all are. You would be shocked to see what comes out after the oil has been drained and supposedly the engine is clean.

[TRD VVTi]

Originally Posted by gdanaher

TRD, this is actually an old mechanics trick to slowly desludge a nasty engine. Say you have a client whose engine is in fact gunked beyond imagination. If you try to clean it too well you run the risk of clogging passages and destroying the engine. You chance the oil, add a pint of atf to the oil and proceed to change the oil filter every 300 miles and top off with a little oil and atf. It will clean the engine. Same goes for flushing a dirty engine with atf for 2 minutes and then draining and changing the filter. Don't need to do it with a low mileage well maintained engine, but not all are. You would be shocked to see what comes out after the oil has been drained and supposedly the engine is clean.

I know all about the "trick". Diesel fuel is also sometimes used.

If it's that sludged, the engine is basically junk anyways. It will be nothing but problems down the road. Note that I mentioned that in the reply you are questioning...

[gdanaher]

I'm not questioning your expertise at all. The topic was changing oil, etc.. and flushing is one approach for an old engine. New clean engines don't need to be flushed. Get the wrong solvent in the engine and you might be looking at shortened seal life as well.