at what condition to change your oil?

[Dr. T]

As per many owner's manuals, oil should be drain when it is warm (not hot). It has nothing to do with climate, oil type, etc....

Therefore, run the engine a few minutes to warm up the oil and then drain. What are the reasons?

1. Allow oil to fully circulate around the engine parts and "hold contaminants" in suspension (that would have otherwise sedimented overnight...either on engine parts or bottom of pan).

2. Warm oil flows better allowing quicker draining and a more proficient oil change without getting burned! Overnight isn't necessary...allow to drain until drops are less than 1/sec...

As far as any addatives...shouldn't be required with good quality oils...oils have their own detergents, emulsifiers, etc....any remnants thereof may clash with the new oil and even render their addative packages less effective not to mention possible engine damage with long term use...

 

[MolaKule]

If you have the Fotomotu valve, it makes draining a lot easier. (See the Oil Filter Section for reference to the valve).

I'm with Ken, Kerosene by itself itself or ATF by itself makes a poor lubricant and a harsh cleaner. Use Neutra or Auto-RX for smooth, slow, crankcase cleanings.

 

[Sciguyjim]

Hello everyone,
I'm new here, this is my first post.
I always change the oil when its warm or hot and let it drain at least an hour. I let it drain overnight once but the next day I realized that it would be "dry" when I started it so I don't do that any more. I agree that once the drips get slow, the amount of oil and dirt still in the engine is insignificant.
I often don't drive the car for several days in a row and someone told me that that's not too good because the engine is left fairly dry of oil when I do start it. I have always used Mobil 1 and have magnets on the filter. Every time I've cut open a used filter there has been metal stuck by the magnets. Some people are surprised by this. Maybe it's because of the dry starts.

 

[Sciguyjim]

BTW, I use M1 5w30 year round. The car is a 89 T/A 5.0L TPI, and I drive less than 5k miles/yr.

 

[Patman]

Jim, first of all, welcome aboard!

Now, onto your situation. Because of all those dry starts, you should look into getting an oil with moly in it. The moly will provide that extra layer of protection when the oil has drained off those parts after a few days of not driving it. Do some checking around on this site and you'll find a lot of info on moly.

 

[Sciguyjim]

Thanks Patman,
I've seen Moly mentioned several times here, it's an organic compound with moly in it rather than the black MoS2 right? For an old car many years ago I used to buy Arco oil with graphite. I was pleased with it, especially the day I lost all my oil somehow (dipstick was dry!). I drove home from work in this condition with no probs.

When I bought my current car I thought of using oil with a graphite or moly additive but I didn't like the idea of the new, clean engine looking like it was painted black inside. And, problems would be easier to spot without the black coating.

I'll do some searching for this other moly.

 

[widman]

Changing oil cold is leaving a lot of sludge in the pan and other places where it can't drain. The Recommendation is always anywhear from hot to warm, normally written as warm to avoid liability suits by over zealous lawyers. Oil change facilities change HOT. Draining aned refilling without overdraining leaves enough film for startup. Here is a quote from a recent Noria Lube-Tips article: "All oil changes should be done with the oil warm. This assures that the contaminants in the system to be drained are already in suspension in the old oil, and that the system has a good film of oil on all the moving parts to protect them during the new filter fill and start up. Automatic pressure prelube systems are still the best answer."
Putting kerosene or diesel fuel in the engine is the worst thing you can do. Neither is a good lubricant, both stay in the bearings on start up.
The residual from one oil to the next will not cause harm in anything but the results of an analisis of the first change.
If you feel you must clean out an engine, (although I've never had the need to try it) I'd go with the auto-RX after reading all written about it.