What Size?? 190E Timing Chain Tensioner Nut
 

I am finally going to get to that timing chain job that I have been avoiding for a couple of months for my 84 190E 2.3 gas motor.

What size allen socket do I need to get the chain tensioner cap nut off?

I dont want to rip the alternator out and then find out I dont have the right tools, only to prolong the job another week.

Thanks folks.

I think you need a 12mm for the plug and a 17mm for the outer ring. This was answered more completely a few months ago when I did my rebuild. You can search on my username and 'tensioner'.