Better to change oil hot or cold?

[Q451990]

I bet this has been covered before... probably many times - but I couldn't find it, so if you guys have an opinion or can give me some search terms or links that would be great.

My Q has been sitting for 4-6 weeks untouched, and is in need of an oil change. Should I start it up and drive it for a while to get the oil hot and circulating before the change, or just drain the oil out cold?

I have heard that it's good to drain the oil while it's hot to keep the dirt and impurities that are in it in suspension. In this case, I wonder if it wouldn't be more beneficial to drain all of the oil out cold, since in theory I should have as much oil as possible drained out of the engine and into the pan?

Thanks!

Heath

 

[Oregoonian]

Drain it 'hot'....drive it for 15 to 20 minutes...let it sit for 10 minutes....and then drain the oil.

 

[Slippery_Pete]

Warm it up. the temp makes the oil thinner and will be easier to drain.

 

[Q451990]

Is the easier drain the only reason? I have no problem letting it drain for a few hours while I replace a leaky p/s hose that's on my list for tha same time on stands.

How about the "holding dirt and varnish in suspension" theory I've heard... any truth to that?

Thanks!

Heath

 

[chubbs1]

Since it has sat so long drain it cold, it will take longer but why run all the garbage that has settled through the engine again. I would normally change it hot but your car had been sitting for a while just drain it (let it drain at least for 1 hr., overnite if possible.

 

[hooligan24]

If you dont have to start the engine to move the car before the drain, just drain it cold. If you have to move the car before the drain, drive it for 20 minutes and then drain.

 

[chubbs1]

Originally Posted By: hooligan24
If you dont have to start the engine to move the car before the drain, just drain it cold. If you have to move the car before the drain, drive it for 20 minutes and then drain.


Very true, I didn't think of that.

 

[chet2]

hot

 

[kr_bitog]

If your oil is good quality and is not used that long, it may be doesn't matter whether you drain cold or hot.

However, if you know that the oil turn like molasses/honey during cold, then it is better to start then engine, drive it for 15 minutes and then drain it.

For me, for whatever reason I still prefer drain it hot because the oil getting thinner and drain easier.

 

[Merkava_4]

You'll get more oil out of your engine if it's hot.

 

[ProfPS]

I drain mine hot after driving, preferably at highway speeds, and letting the car set for 10-15 minutes for the following reasons:
- drains faster
- removes the most oil in a shorter time
- most particles are suspended in oil
- settled particles will flush out faster

most important
- warm restart without a high idle dry startup

 

[mongo161]

More important...IMO....is when do you check your oil.

I check the oil once a week, in the AM, before I crank up the engine. I like to check the oil after it has settled down all night to get an accurate idea of what's in the pan.

In the winter, with cold weather and lots of warm ups, I check sometimes 2 times a week. I don't burn any oil but it's just a habit.....IMO.....a good habit.

 

[Kuato]

Hot oil will drain faster, making the winter oil change easier on you. Plus, IMO since it's been sitting the circulation will help remove deposits from areas where they may have accumulated.

 

[virginoil]

Dopey question, when look back in hindsight. I make this comment not to discourage or criticise you in asking future questions, but rather to imprint my opinion on the matter.

As said above every OEM handbook and mechanic I have spoken say is to drain the oil warm, preferably hot, to get the oil and wear particles in suspension and drain them as quick as possible to remove them.

 

[Eddie]

I used to drain hot & hoter but, with modern oils that hold particulate in suspension, I now drain warm. So after a normal run to the store, I come home and about an hour later I drain the oil and it is still mighty warm.

 

[demarpaint]

Drive the car 20 minutes let the car sit a few minutes, and drain the oil, especially during the winter months.

 

[fdcg27]

I always drain the oil hot, for all of the reasons you cite.
However, if the OP doesn't need to move the car, a long drain cold would probably work pretty well.
It would just take longer.

 

[demarpaint]

Originally Posted By: fdcg27
However, if the OP doesn't need to move the car, a long drain cold would probably work pretty well.
It would just take longer.


I agree, but if the OP doesn't have to move the car, I'd just wait until I had to move the car, then drain the oil hot. I'm just playing Devil's advocate.

 

[Mr_Joe]

I go with hot all the time. But there is a difference between Jan 'cold' & July 'cold'. I want to get any contaminants mixed into the warm oil so it drains out better.

 

[Sayjac]

Quote:
I bet this has been covered before... probably many times - but I couldn't find it, so if you guys have an opinion or can give me some search terms or links that would be great.

Search first from default top box. http://www.google.com/cse?cx=01829996478...F&sa=Search

Opinion now, I prefer to do it hot/warm, but not so hot as burn any body parts. Summer especially, a bit more careful getting the drain plug and might wait a bit longer on the oil filter. Like to do it warm for all the reasons mentioned. Oil flows faster/better, and in theory at least, the crud/particles are held in suspension better than cold. That said, if you read some of the links, many think changing it cold makes no real difference than changing it hot/warm.

So, imo driving the vehicle some to get the engine up to operating temperature is preferable, changing it cold if more convenient, will work too.