Reader asks about oil plug crush washers


James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit questions to jim@jameshalderman.com or follow him on Twitter @jameshalderman, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.

Wheels: Mike S. writes by e-mail:

I would like your professional opinion on the crush washer for oil plugs on autos. I change my own oil, and have never changed a crush washer. I have been buying oil filters from our local Toyota and Honda dealer for our late model cars. They both try to sell me a crush washer.

I wasn’t paying attention this week at the Honda dealer and I paid for it before I realized it was on the ticket. I put it in the drawer with my spare Honda parts.

Cost is not the issue. These washers are aluminum alloy and I could understand if they were damaged. The used Honda washer I inspected today only had a raised radial distortion near the threads on the plug. It was perfectly circular and would not keep the washer from seating properly. I have never had an oil plug leak so I do not see the need to change the washer every time I drain the oil. I use synthetic, so the oil is only changed one or two times a year at 10,000 to 15,000 miles.

Halderman: The vehicle manufacturer recommends that the washer be replaced at each oil change. Is it needed at each oil change? I do not know, but I do know that once a crush washer has been compressed, it will not return to its original thickness and therefore may not be able to seal as designed. I replace them at each oil change. To me, this is cheap insurance and is recommended by the vehicle manufacturer.

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