The pros and cons of power drain plugs

Friday, January 13, 2006

Dear Tom and Ray: Well, it happened again. When I took my 2000 Honda CR-V into the local quick-oil-change place, they extolled the virtues of their "Power Drain Plug" and said I really should get it. The literature that they handed me states: "... it replaces your oil pan drain plug with a special oil evacuation unit ... it allows us to remove your engine's oil without removing the plug ... a more complete removal of the used oil and contaminants." The mechanic stated that he used to drain 4.5 quarts of used oil out of his truck, but now he gets 4.75 quarts out with the power drain plug. I told him that he could not install it until you two said it was OK! Tom and Ray, is this a really dumb idea, or a great one? Thanks!


Ray: It's kind of in between, Julie. It does offer a few advantages, but, in general, I'm not crazy about monkeying with something as crucial and time-tested as the oil pan drain plug.

Tom: This thing is a replacement drain plug that has a valve and a fitting in it. It allows the shop that owns the matching equipment to quickly hook up a machine to your drain plug and vacuum out your oil.

Ray: So who benefits? Well, it's possible that a little more oil gets removed from your oil pan via vacuum -- if for no other reason than that the quickie-lube folks are often in a hurry, so they don't always wait for gravity to deliver every last pint. Is it a big deal? Not really. For years mechanics have been changing oil using nothing but gravity, and it's worked pretty well.

Tom: The other benefit to you is that since they no longer have to remove your drain plug, they're unlikely to over-tighten it and strip it -- or, more importantly, forget to tighten it at all. That IS a significant benefit.

Ray: But these benefits to you are largely overshadowed by the benefits to the repair shop. First of all, it makes it easier for them to change your oil. It's a lot less labor-intensive for them to pop a hose onto your drain plug and flip a switch than it is to unscrew the plug, catch the old oil in a basin and wait around for it to drip out.

Tom: Second, they reduce their own financial liability, because their technicians can no longer be blamed for stripping your drain plug or forgetting to tighten it.

Ray: And most importantly, once you've purchased this special drain plug, you're bound to feel committed to this particular service station forever. After all, it's the only one that has the machine that fits your drain plug, right?

Tom: I'd be a little wary of the oil drain plug. I don't know how reliable the valve is, for example. And the risk, if it were to fail, is potentially catastrophic. So I'm inclined to wait and see how these things perform over time before jumping on this trend.

Ray: So it's up to you, Julie. If you want to be safe, we know that the old way works fine. But if these guys have terrible coffee in the waiting room and you're always eager to get out of there as quickly as possible, then go for it, and be one of our test subjects.

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