Removing oil cap before the drain plug?

(2011-06-03 14:20:19) 1. Richard Says: I've looked an some websites about changing your car oil, and a lot of them say to remove the oil cap before removing the drain plug. I know that it helps the oil flow easily, but is there a reason why I should remove the oil cap FIRST? I would assume if I do, then oil might come out quicker after removing the drain plug and possibly causing a mess. Can I remove the drain plug first, then the oil cap?2. mdk68gto, ase certified m tech Says: the oil cap will not slow down or effect the rate at which the oil leaves the oil pan. it should be done that way so that you know that you can add oil. in some events the oil cap can become stuck and that makes it a bit more difficult to add the oil back into the engine. i have been under 300,000 +- in the shop over 17 years and it just makes sense that way. the oil dipstick provides enough air flow along with the pcv valve or many other orifices on the block.3. Kenny Says: The idea behind it is not of draining the oil faster but the ability to put in new oil after draining the old oil.

Meaning what happens if you drained the old oil and then can't unscrew the oil filler cap(highly unlikely but not impossible ) and put in the new oil. You're stuck.

Good practice in all fluid changes like trans, diff, coolant, ps, is to know you can pull in before taken out. ie drain the differential and then can't take out the fill screw. Ai ya!4. siscokid Says: Sure you can remove the drain plug first. You really don't have to remove the fill cap but it does help the oil empty abit faster. In fact if you are changing your own oil it may be safer to remove the drain plug first since the oil should be warm when it is changed.5. Knuckles Says: If an engine displaces 5.7 liters above the pistons, it displaces at least 5.7 liters in the crankcase below.....meaning you will not have vacuum holding oil in the pan. Most of the time, you have a "swirl" of air going into the crankcase as the air flows out anyway. There's no "air-lock" going on here...6. Mabie Haggerty Says: You might try this places:http://cidai.info/96213/drain-plug7. Angie Askew Says: You got me... I find this. http://buyour.info/98949/drain-plugs8. Jamin Says: From my experience it won't hurt a think to remove the drain plug first. I think you are right, it'll just speed up when you remove the cap.9. It's me Says: If you don't do it in right sequence. It will explode.10. Marble Says: It doesn't matter one way or the other Tag: Removing oil cap before the drain plug?