oil change - draining oil "cold"

Evening Just got myself all set to do my first oil change on the 996. Simple question, is there any big advantage to warming the engine and draining oil hot rather than draining whilst cold but leaving overnight? Just for curiosity! Thanks Chris

I would say yes there is, get the engine warm, but not hot, before draining the oil. If you think about it agitating the oil and the detritus sitting in the sump and around the engine will help it come out in the old oil, this is why oil samples should always be taken mid way through draining the oil :thumb:

I wouldn't bother warming it up. If i'd just come back from a drive, fair enough. But if I'd time, I'd just leave it to drain.

One of the advantages of hot oil is that the viscosity is lower so it should flow out more easily/quickly. But IMHO if you can leave it draining overnight that'll be fine.

What he said, ive always done engine warm.

...hot or cold doesn't matter provided you allow time for a decent drain and is far less important than regular oil changes ! Put it this way...I would rather have a cold oil change once a year than a hot change once per two years!!

A long drain is better than hot i would say .. lets face it , if the car is at operating temps then the oil is 90 degrees .. you try to get the bung out at that temp and your going to get burnt . I tend to have the cars about 50 degrees when i drain them , a road test first .. check some items and by the time its up in the air then im guessing thats about the temp . You Can Not get all the oil out on an oil change .. you will always have approx 1.5 ltrs left in the engine .. this is due to the design im afraid .. oil gets trapped in places that only an engine strip will remove . Best way .. leave it draining overnight .. you will get the maximum out that way .

thanks for the input, getting it warm to mobilise any ***** into the oil before draining makes sense in my small brain! I think I will take a little of everything you say, drive it, drain it, leave it overnight! Regards Chris

I do both but it depends on the circumstances. If its already in the garage I will drain it cold and leave it overnight and is my preferred method. My logic is if it is cold, all the oil that can drain to the sump is already there, running the engine distributes the oil all over the engine again and you won't get as much old oil out as a cold drain over night.

...totally agree; best method in my opinion.

Spot on :thumb:

Well, if some one had told me that I'd have laughed in their face........ reading it though makes perfect sense ? Starting it up flings all the oil around the engine and whilst the particles will be suspended in the oil, of which 1.5 litres remains, the cold Oil will surely have the debris sat at the bottom of the pan which will be removed when the plug is taken out ? In the case of pure unadulterated love and affection you could always rinse and repeat ? Just to squeeze every last drop out..... it's always handy if you have an old diesel to use the nearly new oil in ?

Why not both. Get it hot and then drain it overnight?

Dunno, seems again like a logical suggestion but in my head I'm thinking about the hot engine cooling from hot to ambient temps with no oil in, Or as suggested from 50 degrees would seem even more plausible, the point I was trying to make was that draining an engine cold actually seems pointless, but when you I think about it !!! All the crud is there in the sump just waiting to be drained. Which ever route, regular changes with good quality oil.

There is no crud as such .. that's back in the ford escort days of poor quality fuel . oil and how engines ran .. usually rich ! we used oil thinning additives back then on an oil change to break all the crud down . Oil comes out pretty clean on Porsches compared to the old days .. i was there then lol . If we wanted to be technical .. oil expands when hot so in essence it occupies a larger area .. If at operating temp and then drained and left overnight you would get fractionally more oil out due to the expansion of the oil . I feel we are into milliliters at this point though . Cold or hot and you will get the most out via an over night drain .. you will still have the best part of 1.5 ltrs still in the engine though . To be perfect .. change the oil .. run it to operating temps then change it again to dilute what's in there with fresh .. dump it and refill with new again .. probably down to less than a 5% mix of old oil with new . getting silly at this point though and rather expensive