the bottom bolt of the belt damper strut managed to come loose and eventually made contact with the water pump pulley. I think it got wedged somewhat and broke one of the "prongs" where it attaches to. so now i have no way of fastening the bottom part of the damper strut to the "tensioner arm?" (don't know what its called... its the "arm" where the spring, the pulley and the strut attaches to.)...

my question is... IS it CRITICAL to have that damper? Is the belt in danger of de-railing?

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

I think you are talking about where the shock absorber connects to the tensioner body that counters the spring. If you broke the two ears that receive the through bolt, and now have no connection to the shock, I would imagine it is possible for the belt to jump, say when the AC compressor kicks in, etc. That dampener slows down the jerking reaction generated by that spring, keeping slack out of the belt.

You may get away without the belt jumping off track, but I would replace the tensioner as soon as I could. If your belt comes off while driving, you probably wouldn't know about it until the temperature started to rise out of control, and by then, it might be too late. Risky I'd say!

If the belt comes off on the 603, you lose the alternator and power steering.

You get an immediate idiot light on the dash for the alternator and the steering won't respond normally.

Be hard to ignore unless you are a complete idiot.

It might be a good idea to check tightness of the large hex center bolt that fastens the tensioner to the block too, as I remember reading a thread here not too long ago about that bolt coming loose and being loose caused threads to strip in somebodies 603!

The 603 fan pulley is not the water pump pulley.

I don't know exactly what the shock does but you're talking about a 603 that's sensitive to overheating.

Sixto
95 S420
87 300SDL

there is a thread on the tensioner replacement, see sixto's description:
603 Idler Pully Replacement - Fan Belt
The big bolt is put on real tight, 80 + ft lbs and as I recall GSXR used locktite on his too.
Incidentally! Carrameow, Ken300D and gsxr have had timing covers crack where the pulley or tensioner mounts, there is a new updated cover available that presumably is reinforced or stronger in that area.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Why sure it is! The fan, fan clutch, bolt to the waterpump pulley on my 603! In order to remove the single serpentine belt, belt tensioner, you need to remove the waterpump pulley wheel off and out of the way.

thanks guys!

that's what i was afraid of...
i remember trying to remove that "tensioner body" before... the bolt was hard to turn that i eventually gave up... i was afraid of breaking the timing cover, which already has a crack on the upper left corner. I'm afraid of breaking off where the pulley attaches to.
Anyway, i do need a new cover anyway...

thanks guys

__________________

85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

Dang M103 still haunts me

Sixto
95 S420
87 300SDL

I just replaced the shock on my 300d and it was a REAL PITA, anything in the front area of the 603 is a PITA, I wonder if you can just replace that spring with a pull bolt somehow, I think it will be more reliable and can just be checked periodically for belt tension, what do you guys think?

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87 300d Turbo 241K with original #14 head (blue)
87 300d Turbo 198K will run great again someday (silver)
84 300sd sold ( buyer drove it to Paraguay )

what i do is i remove the fan shroud, the fan blades, then the pulley... after that i can access the bolt holding the damper... it just takes 15-20 minutes.

it's easy in my case coz my shroud has been cut near the upper tranny cooler line, so its easier to remove even with the fan still attached. i just tie-wrap the joint when i'm done

__________________

85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

The spring for the belt tensioner is necessary in order to retain a predetermined belt tightness and to absorb momentary slack/shock in the serpentine belt such as when the A/C compressor cycles. The dampener smooths out the movement of travel the tensioner wheel and tensioner spring makes. Without these mechanisms, the relatively thin serpentine belt will stress beyond design limits rendering them subjective to failure.

I've replaced the tensioner arm without removing the fan. I don't think I even moved the shroud. The pulley has to come off/go on with the tensioner arm in place. I guess the SDL radiator is set forward enough to makes the job possible.

It's replacing glow plugs with the manifold in place that I can't do.

Sixto
95 S420
87 300SDL

There seems to be quite a bit more room under the hood for a 126, according to members here, and less forgiving for space in the 124. But I haven't found anything that required drastic measures to access yet, and I've only replaced one GP, #3, so far, that did require using a 1/4 drive ratchet with a universal joint and socket extensions!