Help, removing tensioner shock
 

I'm glad I've discovered this great forum. Have enjoyed reading past posts
and learned considerably. At idle my '93 190E makes considerable noise which my local MB service man diagnosed as the shock for the tensioner.
Idler comes off no problem, but the apparent T30 Torx screw that holds on the shock I can not get off. I noted on the new shock that the collet is threaded and has an opening for a 'captured' nut. This nut then basically
appears to act as a lock nut which might explain why I can't get the torx screw out. In addition, this torx screw does not have a particularly deep recess..... is there some trick to removing this screw? Or should I just grind it off? Any pointers would be much appreciated.

cheers, guenter

ps this difficulty is really scarrying from doing a water pump replacement on my '89 300E. Is the water pump replacement a job for the dealer?

tensioner Shock
 

I have an 88 3000 SEL. My tensioner shock is held on by two hex screws so I can't be much help there. However, as to the water pump replacement that is not too bad. As I recall I need a set of 3/8" drive allen wrenches a long 3/8" extention and universal to get at the pump. Be sure to replace the short hose between the pump and t'stat housing when you replace the pump as you can't get it off without removing the pump. I think that you will have to the remove the tensioner to perfrom this removal.

Many thanks for your reply Lenny. Am I correct then in thinking that I do not need to remove the radiator and fan to remove the pump? I need to:
1) losen belt
2) unbolt pump from engine (for which bolt; ie roughly where, does the universal come into play?)
3) remove pulley from pump
4) install new pump in reverse order after replacing the leaking 2" bit of tubing that I've been unable to replace till now.

- cheers, guenter

It helps to remove the radiator for 1. room, 2. tools don't go through the core.

The fan, belt and tensioner must come off as well as the PS pump. The 4 bolts are revealed. The uni-joint goes on the rear top bolt through the intake manifold. Be prepared with another u-joint in case the first one breaks. It's an odd angle. Get a new O-Ring for the heater pipe joint.

Use grease to hold the large o-ring in place. Get a new connecting hose and while your in there, new radiator hoses etc.

Tensioner Shock/Water Pump
 

You're Welcome
I agree with WBain. However, you can avoid removing the radiator while protecting it by placing a thin piece of plywood over the core. As he stated, you will need to remove the fan. In order to hold it stationary while removing the bolts, you will need to place a screwdriver nail etc. into a slot in the fan pulley provided for this purpose. The universal allows you to get to the allen head screws which are not easily accessible.

many thanks for the pointers all around ..... with these heads-up's I'm going to give an at-home r&r of the pump a go!

cheers

ps. first I need to replace the tensioner shock in my wife's '93 190E. I can't believe that MB used a M6 'torx' round head bolt to hold the top of the shock behind the idler wheel - this big torx is truly crap! the 'star' recess is so shallow that there is nothing for the bit to bite into if the bolt is even a little seized - which of course it is.

I finally managed to get the torx screw holding the tensioner shock out EASILY by using a 'Drill-out' at the end of a socket wrench. It's able to 'grab' the bolt without having to put much pressure on it.... hope this bit of info is useful.