How to remove serpentine belt tensioner assembly?

[Roy_Josef]

Hi fellas. Previous owner buggered up the bolt head that holds the serp belt tensioner in place. I also suspect the tensioner arm itself is seized as I can't get it to budge turning it clockwise as you are supposed to. The bolt is actually longer than the space between the tensioner arm and the engine case leading me to believe the whole assembly has to come out to change the bolt. Can anyone comment on this?

[JFP in PA]

The belt tensioner is a nut on the end of a bolt that passes thru the spring arm. There is a great diagram of this on page 13-2 in the Bentley manual. You need to get a wrench behind the tensioner pulley and either screw the bolt back into the spring arm, or remove the tensioner pulley itself and then screw the bolt back in, after which the tensioner arm will rotate counter clockwise.

[Roy_Josef]

Thanks for the reply but I'm not sure you're picking up what I'm putting down. I need to get the bolt out from behind the lever arm. I've already got the pulley off but the bolt is longer than the space between the lever arm and the engine case leading me to believe the whole lever arm assembly has to be removed to change out the bolt. Clear as mud?

[JFP in PA]

Totally, but you are not paying attention either. The bolt that passes thru the “spring arm” of the tensioner (red arrow) can only be removed after the combination belt tensioner housing/hydraulic pump mount has been removed from the top of the engine (read a lot of work, and direct from the OEM 13 volume service manual set). The bolt you are having trouble with needs to be screwed all the way back into the spring arm (towards the pulley) before the arm can swing freely and the belt removed. I am suggesting that you try to screw the bolt back into the position it is supposed to be in rather than try to remove it, which cannot be done with out getting at the back of the housing it passes thru to remove the “tensioning element” (Porsche for the tensioning spring assembly) and then pulling the spring arm forward. But to get to that point, the power steering pump (green arrow) and AC compressor (yellow arrow) has to come out of the way, the housing unbolted and the tensioning spring assembly removed……………….



In this straight on shot of a 996 motor (same layout as yours), you can just see the tensioner arm (coming off #7) going back into the big aluminum bracket that holds the powersteering pump (#1). The AC compressor (area #5) is already off in this shot.



And this is what the arm looks like out of the assembly:



Try and get the bolt back in, you will save yourself a lot of grief if you can......

[Roy_Josef]

Thanks for all that. I suspected the whole assembly had to come out to replace that bolt. Can it be done with the engine in situ? My biggest concern is the 'head' of that bolt has been totally chewed and I needed vice grips on it to hold it while I spun out the 24mm pulley itself. I am hesitant to reuse that bolt as I will need vice grips on it again to re-install the new pulley. Not to mention my suspicions that the lever arm itself is seized in place...

[JFP in PA]

The tensioner assembly can be removed with the engine in the car; there is just a lot of stuff in the way. And, I finally found a diagram for you:



#10 has to come off before the arm, #8, can be released and removed to get at the problem bolt, #6. But as #10 is on the back of the housing, all the other aforementioned stuff has to come off first.

[Roy_Josef]

Thank you very much for that. Looks like this is going to be fun...

[JFP in PA]

That is why I suggested trying to screw it back in and leave it alone.............

[Roy_Josef]

What would you think about cutting out that bolt completely and then using a new bolt going through from the other way? So...it would go through from the front of the pulley first (threading through it) and then I'll use a nut to secure it on the back side of the lever arm. Why do all this? Because the head of the original bolt that's in there right now is really chewed up and I'm trying to avoid pulling that whole assembly out at least until the next time I drop the engine.

[JFP in PA]

I suppose it might work, at least for a limited time frame. The OEM bolt literally forms a stud that the spacer, idler and its front nut tighten onto. What ever you use would need to be of good quality (e.g.: grade 8) as you do not want the belt load to cause it to deflect off axis, which could also lead to issues with the serpentine belt not wanting to stay on. As the OEM bolt was originally a “micro encapsulated” fastener, you would also need to use LocTite on the threads to make sure nothing loosens up.

[cacha79]

Before I begin I would like to thank this forum for all the help I have gotten on previous projects. My new project is replacing Part# 997-102-260-00-M260. JFP, Do you know where I can find instructions on how to remove the Tensioner assembly? I don't have the OEM service manual and so far searches in google have been unsuccessful.
Have a good one all.

[JFP in PA]

I'm afraid you may be out of luck unless someone has posted a DIY somewhere; the OEM manual is the only source I know of, and even that is not all that great..........