Bolts on the intake are not fun. I use 1/4" drive tools and extensions & universals. I usually have the extension up tight against that ear but it does work. On my 190DT I noticed the bolts were all pretty loose so I tried a ball end hex and it went a lot easier. If you try the ball end hex be careful because its a lot easier to strip bolt heads. I have had the manifold on and off serveral times on my 300DT in the past 155Kmi and have never used a torque wrench.

Regards,

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Brian Toscano