Crush washer torque

[Sprintcar26]

How do you use a torque wrench on an oil drain plug when you're using a copper (or any metal) crush washer. Any time I've used them (often) the resistance from the pre-crushed metal seems high enough to completely throw off the torque reading. That you might get a reading that was spec for the final drain bolt setting, but at that point, it's only crushing the copper. Problem, or am I overthinking it?

 

[PandaBear]

I never bother using torque wrench on a drain bolt. Usually finger tight then about 1/8 turn is all I do.

 

[grasscutter]

The torque speculation is supposed to take into account the copper crush washer. If not, go to plan B.

 

[rstsco]

I use Honda-branded crush washers and torque to the specified torque. At some point I to have to trust it will not fail me. Having said that, after an OCI, I run the car just long enough to build up sufficient oil pressure, shut it off, and check for leaks around the drain plug and filter. Then I'll take the dogs for a ride and check for leaks again. I'm always checking the garage floor for any drips. Yes, I'm aware I'm retentive. Trust, but verify.

 

[benjamming]

The torque will overcome the crush portion of the washer (which is not 100% of the washer thickness) and provide the clamping force required. It's possible that some aftermarket crush washers aren't controlled well enough or at the right value to coincide with the required torque value set by the vehicle manufacturer.

Are you sensing this issue with crush washers purchased from the vehicle manufacturer? If so, which manufacturer(s)? If not, then you might try using crush washers from the manufacturer & see if the concern persists.

 

[Kira]

The drain plug used in the Volvos I've owned has a protruding shoulder which will enter a slightly larger recess in the pan.

The 18mm aluminum washers yield under the fastening torque, disforming them a bit. It's easy to feel during tightening.

This kinks the aluminum (in cross section) in a definite pattern rather than the mere concentric scratches seen on copper washers used by Saab.

 

[Donald]

My F250 PSD has an o-ring on the oil drain plug. Not sure why more cars don't have that.

 

[DCDG]

Yeah the Nissan style rolled copper crush washer gives you a pucker factor when tightening to torque spec, I nearly had to change my draws after torquing one on the wife's plastic pan Rogue you could really feel the washer flatten out. This vehicle no longer gets drain pan oil changes strictly the extractor now. When I had my steel pan Nissan I would tighten 90+ % muscle memory and send it with the torque wrench that worked for me.

 

[RooflessVW]

How do you use a torque wrench on an oil drain plug when you're using a copper (or any metal) crush washer. Any time I've used them (often) the resistance from the pre-crushed metal seems high enough to completely throw off the torque reading. That you might get a reading that was spec for the final drain bolt setting, but at that point, it's only crushing the copper. Problem, or am I overthinking it?

You just described how crush washers work.

Measuring tightening torque on a fastener is a substitute for the measurement of the tension (clamping force) on a fastener.

How then, if you're tightening a fastener to the same torque, would the presence (or lack of) of a crush washer affect the final clamping force?

 

[TomYoung]

How do you use a torque wrench on an oil drain plug when you're using a copper (or any metal) crush washer. Any time I've used them (often) the resistance from the pre-crushed metal seems high enough to completely throw off the torque reading. That you might get a reading that was spec for the final drain bolt setting, but at that point, it's only crushing the copper. Problem, or am I overthinking it?

Set torque wrench to specified setting. Put new crush washer on drain plug. Install and tighten with torque wrench until it clicks or beeps or shows the correct torque. Don’t ask questions about throwing off torque reading from pre crushed metal. (No clue what that means)

 

[RocketRod69]

Depending on the thread pitch of the plug, you have to be careful using copper as over time the fine-thread pans can get damaged. Rolled copper plugs are great for fine threaded pans!
(See profile picture) I use FelPro composite gaskets on those engines...and finger tight plus a quarter turn.

 

[Hirev]

My 2 chevys and 1 ford use a o ring on the oil drain plug this is one thing they do get right.

The torque values given for oil drain plugs is two fold (1) secure the fastener (2) protect the integrity of the threads. The crush washer or o ring is just along for the ride.

 

[RocketRod69]

My 2 chevys and 1 ford use a o ring on the oil drain plug this is one thing they do get right.

The torque values given for oil drain plugs is two fold (1) secure the fastener (2) protect the integrity of the threads. The crush washer or o ring is just along for the ride.

Both are coarse threads! GM pans nearly NEVER strip the threads.

 

[2005jettatdi]

I always torque mine by feel. I told my kids, "About like so." It has worked fine for decades.

 

[grasscutter]

There are some instances where I like to 'feel' the tightness. A drain plug would be one of them.

GM drain plugs are fantastic. When they get tight, they get tight all at once.

I prefer that over something that gradually gets tight.

 

[Dborch41]

I never bother using torque wrench on a drain bolt. Usually finger tight then about 1/8 turn is all I do.

I wouldn't do that with a crush washer. Those need a couple of turns past finger tight just to deform, then you need to apply the actual sealing torque.

My Nissan is like that, I used to use a torque wrench but eventually just developed a "feel" for it with a regular ratchet.

 

[IndyIan]

I just go by feel, tighten with one hand on the head of the ratchet and feel how the washer is deforming, and then when it takes noticeably more torque to turn as its turning you are getting close, and then just go with one finger on the end of the ratchet until there's no chance for it to back out.
The only time I've had trouble with metal crush washers is following the directions on the box for number of turns after being finger tight, which left spark plugs to loose... They felt to loose and they were, as they worked loose in a week....

 

[Snagglefoot]

I notice Honda/Acura are fans of crush washers. A friend was helping me and asked where the crush washer was. The what? Turns out he's had nothing but Honda's and Acuras. I've had Fords and Chevy's.

 

[RooflessVW]

I wouldn't do that with a crush washer. Those need a couple of turns past finger tight just to deform, then you need to apply the actual sealing torque.

My Nissan is like that, I used to use a torque wrench but eventually just developed a "feel" for it with a regular ratchet.

A couple turns? In what world? "Couple turns past finger tight" is stripped.

 

[2strokeNorthstar]

Never once torqued a drain plug and have never stripped one or had one back out. I had 2 issues over the years. Dealer under tightened and leaked, Jiffy Lube stripped out the pan using God knows what to tighten it. They were both probably instructed to torque them