390 drain plug torque specs

[David Greenburg]

I have usually done drain plugs by feel, but getting ready for spring oil changes on my cars, I noticed that the torque spec for the ‘61 was increased to 30-50 ft lbs, which is substantially greater that the 25-30 spec’d for ‘60. I’m wondering if perhaps there were complaints of leaks with the earlier engines, and GM figured out it was okay to make them tighter. Although if that were the case, you’d think it would have been addressed in The Serviceman.

[Jon S]

I would think 50 foot pounds would strip the threads on the oil pan.  I have never seen any mechanic at a dealership or service center ever use a torque wrench on a oil drain plug.

[Roger Zimmermann]

I would think 50 foot pounds would strip the threads on the oil pan.  I have never seen any mechanic at a dealership or service center ever use a torque wrench on a oil drain plug.

In the fifties, the oil plus is located in a way a torque wrench cannot be used.

[David Greenburg]

50 did seem way too tight.  I went up to about 36 and stopped.  On the ‘61, there is room to get a TW on it, but I think as Roger notes, the ‘60 and earlier design doesn’t leave enough space.

[bcroe]

I figure the more times the oil is changed, the less torque it takes to wear it out. 
Just did the 61st oil change on the H...., I now use some of that blue gasket maker
to keep it sealed without too much torque.  Bruce Roe

[The Tassie Devil(le)]

Another reason why oversize plugs are available.   Nothing worse than a heavy-handed service attendant.

Bruce.

[Jim Govoni CLC 20546]

Maybe it should be (in) inch pounds, many things are on the early 40's cars?  Just a thought.

Jim

[Clewisiii]

I made that mistake once. Not paying attention and I tightened down a cast valve cover using foot pounds instead of inch pounds.

[Dan LeBlanc]

Maybe it should be (in) inch pounds, many things are on the early 40's cars?  Just a thought.

Jim

That would be 4.16 Ft-LBS.

[Jim Govoni CLC 20546]

Thanks Dan, that sounds about right!