Yes, I can go under and pull the other nut, and size it... But the car is parked offsite, so I'm hoping someone can provide the size....

On my 240D, on the passenger side, the AT cooling pipe mounts to the oil pan with a little looped piece of metal. It's loose. The nut is gone.

I think it's because my slow idle is really rough with AC on and/or in D. Fast idle is smooth as silk.

So essentially I need to replace that nut. Any idea of the size?

Thanks!

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)