tensioner problem
 

Im aware of the issue of older tensioners need replacing, but this one slacked and tightened fine. Problem is, for some reason I cannot get the 19mm bolt to thread. Its not crossthreaded, just not catching a thread. Has anyone ever had this problem?

What YEAR and MODEL car??

Oh Sorry! Lol.. its an 89 300e

Does it have a reverse thread cut? Some of them do.

So you mean the large bolt that goes through the tensioner itself?

The tensioner rod (the reverse-thread one) may not be seated on te rear of the tensioner body correctly, not allowing it to seat up against the engine properly. The little bracket on the bottom end can be mounted two ways, right and wrong. Ask me how I know.The big bolt is right-hand threaded.

DG

244brick, did you only loosen the 19mm bolt a few turns, or did you completely remove it? If you completely removed it there is a chance it's misaligned with the threaded hole. Use a drift pin to align the tensioner with the hole, and try again. If you only loosened the bolt a few turns then the threads must be stripped.