A thought on changing oil when hot or cold.

[moribundman]

quote:

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okay I was unclear then, the oil system is drained when you remove the filter, prefilling the filter is good and I do it as well, but starting the engine after the change still requires more time to fill the system.

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got boost?,
Yes it will take a moment to pressurize the oil system, and as I said, I do keep an eye on the oil light when starting up first. But the light goes out on my (relatively) new car like always when I start it up, while on my older cars it would sometimes take 20 or 30 seconds after an oil change. Also, since the oil retention valves keep some oil near the cams, oil is almost instantly available.

 

[pscholte]

M'man,

I prefill the oil filter (2 doses...initial and then, after that soaks into the filter element, a second one) and on all my vehicles the light goes out in less than 5 secs.

[ July 14, 2003, 06:32 PM: Message edited by: pscholte ]

 

[Al]

We have had this discussion before.

I agree with Patman's answer. I'ts good to get the hot filter off as soon as possible to prevent seepage into the pan. A hod drain is the best. Better velocity flushing things down.

I generally follow with a half quart of cheap dino oil-to help further get rid of old oil. I do it with the engine resonably warm so that the flush oil flows well.

 

[Patman]

The only problem with that idea Al is that you're then mixing in a little bit of the cheap oil with your good synthetics. I know it's only a small portion and most of it comes out but it's still something I would lose sleep over.

When I do occasionally pour fresh oil into the engine with the plug still out, I always do it with the same brand of oil that's going into it next.

 

[ex_MGB]

Couple of factors in draining oil besides doing while oil is toasty:

1. Be sure and take out filter while drain plug is still out. On some cars you'll note a sudden burst of oil out the drain.

2. I have a big hydraulic floor jack as well as a Eastman uni-body adapter for the jack. Ergo, jacking the car is a cinch. Point being, look where the drain plug is in relation to the pan. Jack the car so that the oil pan is tilted with the drain plug down. You'll be pleasantly surprised at the extra oil which drains.

I agree with pre-filling the filter and giving a wee bit of an oil flush (3 oz) with the same oil as to be used for the fill.

[ July 14, 2003, 07:34 PM: Message edited by: ex_MGB ]

 

[YZF150]

Or, you could let the vehicle sit all night, then, at oil change time, build a fire under the pan. Bring to simmer, remove heat source, drain.

There--all the bad cooties will drain from the top end and rush headlong into your oil pan.

Ta Da.

 

[Al]

quote:

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Originally posted by Patman:
The only problem with that idea Al is that you're then mixing in a little bit of the cheap oil with your good synthetics. I know it's only a small portion and most of it comes out but it's still something I would lose sleep over.

When I do occasionally pour fresh oil into the engine with the plug still out, I always do it with the same brand of oil that's going into it next.

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Yea I thought of that but my thought is that it's still SL rated oil and its clean[. To me that outweighs the other factors. I could as usual be wrong though

.

 

[pscholte]

I'm disappointed...not one of you has said you change your oil while it is tepid.

 

[greencrew]

Better to drain and fill when hot.

1) You get more oil out because it flows better
2) Dirt is suspended in the oil and not yet settled on the bottom of pan.
3) New oil warms up and flows better to empty filter.
4) Remaining oil on engine protects on startup.

 

[cryptokid]

i like to drain my oil scalding hot. i dont mind burning my hand every oil change. i have a high tolerance for pain.
usually i drain the oil only after running the engine for a couple hours, i have no idea why i do it this way but thats just how i do it. i dont think it helps.

 

[greencrew]

cryptokid, I agree, it just can't help enough to make it worth the pain.

 

[S2000driver]

ME: After a long drive, park the car and immediately open the Fumoto drain valve. Let drain several hours. As much dirt is in suspension as possible.

Replace oil filter while the car is cold, it's looser when cold and you won't burn yourself. Oil doesn't splash as much.

Fill cold crankcase with oil, there is less thermal shock to the top end from cold oil hitting hot components.