One thing about this thread that is interesting to me, it seems like it if difficult to find the manufacturer’s recommended torque for oil drain plugs. I haven’t checked my Corolla’s FSM yet, but I can’t see it on AllData at all. There’s dozens of torque specs there on AllData, like for bearing caps and oil pump attachment bolts & the like, but nothing I can see for oil drain plug torque. I wonder why? Is it just b/c most everyone does it by feel?
You piqued my curiosity, so I looked into my own manual for my Toyota 4-banger, a 2AZ-FE. The spec I found is 30 ft-lbs. I cannot guarantee that it’ll be the same for your engine, but it’s something to start with.
GM seems to provide an oil plug torque value in their manuals, at least in the couple that I checked. They even gave a torque value for the oil filter, which I had never seen before.
I just did an oil change on a 2004 Chevy pickup with the 5.3L V8 that has a cast aluminum pan. I tightened the drain plug using the “snug” method. After this thread started, I looked up the torque spec in the manual (18 lb-ft). For the heck of it, today I checked the torque on the plug I had “snugged” by progressively increasing the setting on my torque wrench until I reached the setting where the plug finally budged. It turned out to be around 36 lb-ft or so–double the spec. I guess I have to ease up on my snugging. Even at 36 lb-ft, it certainly wasn’t as tight as it was when I removed it.
OK4450 brought up the issue of possible liability if a shop were to repair stripped drain plug threads using a Heli-Coil. I just discovered that many of the GM LS-series engines with aluminum pan came from the factory with some sort of thread insert (presumably some type of Heli-Coil) for the drain plug.
“Breakaway” torque is always much higher than installation torque. Many years ago as a young engineer in the manufacturing industry I had occasion to do a study on a particular application, and in that application the breakaway torque was pretty consistently about 40%-45% higher than the installation torque that was used. Different materials, thread types, thread depths, and other variables will cause the torque difference between installation torque used and breakaway torque to vary greatly by application. These numbers cannot be transferred to any other application.
Me, I’ll stick with “snug”, when using a “stubby” wrench. I think it’s the best torque spec for oil drain plugs overall.
Over the years I’ve seen a lot of stripped or generally botched up oil pan drain plugs both on steel and aluminum oil pans.
There is only one of those cases where a new pan was actually needed and there was a story behind that one.
I’ve never wrecked one either. I should add that I always use a new crush washer on the Acura.
I assume Hyundai gives the specs on my car (Sonata) because they have it posted on the forums, both for the filter and for the drain plug. I tried to go with the recommended 30 ft/lbs on the drain plug after I had used the snug/feel technique and I felt it was getting too tight. So I went with the tested method of snug and no leaks.
With a car that is new to me, for the first few oil changes I check around the plug a dat or two after the change just to get a feel for it.
I found this helpful…
http://www.hollonoil.com/OCH/Engine%20Drain%20Plug%20Torque%20Chart.pdf
When I asked this question 9 years ago, I had already been changing the oil for that car for 22 years. I would describe the amount of tightening I do as “not quite snug”. But an early message by Tester is significant here: oil in the threads lubricates the stopper, so the amount of torque needed for a good seal is not much.
In addition, I have been winding a few layers of teflon tape around the stopper. This also has the effect of lubricating the stopper, meaning even less torque needed for a good seal.
I started using teflon tape after my first oil change in 1994. There had been a slight drip from the stopper before and after that oil change. From the second oil change through now, with the help of a little teflon tape each time, no more drip.
I just snug it up with a ratchet and the a quick tug to make sure it’s tight. Never had a problem. I see no reason for Teflon. I use a new crush ring on the Acura each time. On the Pontiac I just buy a new plug from time to time with the new washer attached.
I do what @Bing and others have said - just by feel. I have used the teflon tape in the past, but got off of it once I got squirrely about the possibility of having shards of teflon end up in the oil pan to clog the pickup. You can make sure the plug’s threads are clean, but not so much the threads on the pan. Doesn’t help much of anything anyway. Pay more attention to the washer.
Mr. Google agrees with you and says teflon tape will break done under the engine heat so it should not be used for an oil pan plug.
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Teflon tape near the head of the stopper, so it forms a good seal among the threads of the stopper and drain pan hole only. Not along the full length of the stopper so there is teflon wrapped around the part of the stopper that protrudes into the oil pan.
Finesse.
Bought a baggie full of white nylon crush washers of the right size via eBay in 2016. When I change the oil, if the old washer seems like it is thinner and more brittle than when new, I replace it with a new one.