E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

Water pump repair, notes on the job so far (long)

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Old Nov 3, 2004 | 03:42 PM
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From: Eastern Washington
1991 300E
Water pump repair, notes on the job so far (long)

Water pump went bad. It was still pumping coolant fine, but the shaft bearing is gone. With the belt off, I can shake the pully all around, and it was making a horrible racket before. I decided to replace the pump, radiator hoses, belt, tensioner, tensioner damper & adjustor, and idler pully. Might as well since I had it all off anyway. My fan clutch's performance has been marginal since late last summer, but most all my miles are on the highway so it really hasn't worried me. My temperature never went above 100 even around town, always at about 82 on the highway, just that the fan never engaged. I also wanted to inspect my radiator. I'm taking this job nice and slow, mostly becuse my free time is limited and I'm still waiting on a couple of parts.

Well, so far I've drained the coolant and oil, sucked the power steering pump resevoir dry, removed the fan, fan shroud, and radiator. The neck on the radiator looks fine, but as a precaution, I am going to build and strengthen the neck by making a weld 'throat' (bead) around the neck with some JB Weld. Hopefully that will add some mechanical strength. I have 75K miles now, and I think I'll plan on replacing the radiator with the good Behr metal reinforced one in the spring or summer, closer to 90 or 100K miles.

I wasn't able for the life of me to get the fan clutch off. I tried the method used in the service manual, and it chipped the metal casting on the fan bearing bracket off where it locks the holding tool in place (that small hump). I'm sure that if I had been using the right tool, and not an allen wrench, then this wouldn't have happened, maybe. Last night I figured out that if I pop the cover off the front of the idler pulley, then remove the bolt and idler pulley, I had just enough room to put a strap wrench around the fan pulley and hold it in place. I had to use a breaker bar on the fan clutch bolt. It literally broke free. Inspecting the bolt threads, it looks like there was galvanic corrosion on the threads that rust welded it in there. So I finally got it off. The strap wrench to hold the power steering pulley and water pump pulley and those come off easily too.

I then removed the bolts holding the belt tensioner, damper, and power steering pump and removed that and moved the power steering pump aside, then called it a night. Tonight I'll tackle those evil looking water pump bolts. Hopefully I'll then be able to install the new parts and put it all back together. I'm waiting on a new upper radiator hose, the idler pulley, and some Toyota silicon fluid to refurbish the fan clutch. Hopefully that'll work, since I don't feel like paying for a new one right now. If all goes right, I'll have my car back on the road by this weekend. I might even have time to finally get to the front brakes. (I have some cross drilled rotors and new pads I've been waiting to install. I was going to wait for the brake sensor light, but maybe I won't.) I should take some digital pictures, but I don't have anywhere to post them. Its definately been a learning experience so far.

Last edited by Strider93; Nov 3, 2004 at 03:45 PM.
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