I usually grab my 13mm socket and then find which smaller one barely fits inside it and then use that as a gauge. It'll usually be your 10mm.

The mounts are 17mm when new and at 13mm, as Sixto said, are considered bad.

You can also lift the engine 1/4" with a floor jack and a rubber bushing between it and the engine and see if the vib gets better.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)