Should You Be Using A Torque Wrench On Oil Drain Plugs?

It's fine to remove an oil drain plug with a wrench or socket. But should you use a torque wrench when reinstalling the drain plug (assuming you don't have a quick drain plug)? It seems like a simple question, but opinions are all over the place, ranging from "It's mandatory" to "I've never done it in 50 years" within the same forum post. So what's the right answer?

You can find handy charts listing oil drain plug torque specs for most cars built between 1992 and 2011. The fact that there are torque specs at all is a clear indication that the auto manufacturers want you to follow them. A torque wrench is the tool to make sure a bolt is just the right amount tight, not too much or too little. Therefore, the technically correct answer is that you should use a torque wrench to tighten oil drain plugs. 

However, you shouldn't have problems with not using a torque wrench on oil drain plugs. These torque specs are very low, 18 to 25 lb-ft in most cases. With enough experience, it's possible to simply tighten the drain plug by feel to "snug," or perhaps "gutentight" if working on a German car.

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The only thing the oil drain plug holds in the car is oil. It does not have to be super tight, like the lug nuts that keep your wheels from falling off. The drain plug and threads on the oil pan it screws into aren't made to take a lot of force, because they don't need to. If you jam the drain plug on with an impact wrench or a strong arm, you'll probably strip out the threads, causing the plug to spin around and not come out. At that point, a tap and die kit might be able to rethread it, but it's probably best to replace the oil pan and not risk metal flakes getting into the oil pan.

Look up the torque spec for your particular vehicle. For example, a 2004 Dodge pickup has a spec of 25 lb-ft. Some, such as the Cadillac 3.2L V8 and the Audi R8's 4.2L V8, can be as low as 7 lb-ft of torque. You'll need a rather small torque wrench to measure this low. It's a good thing to add to your collection of automotive specialty tools. Once you torque the drain plug to spec a few times and get a feel for how much oomph it takes, you may be able to replicate it on your own. But if you have any doubt, use the torque wrench. It's better than stripping out the oil pan.