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Discussion Starter #1
In the interest of not hijacking my own thread I have some questions.

I am going to replace the water pump on my 98 E320 (112 engine). What is everyone's thoughts on the following:

Should I replace the thermostat while I am in there?
Should I replace the serpentine belt?
Should I replace the radiator hoses?

I ask because I have zero indication that any of these are bad. I always like to hear everybody's opinion and reasoning. I am not the sharpest knife in the drawer (more like a wood axe) so I always get as much information as possible.

Drew
 

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MB thermostats usually outlast the engines. If you didn't have any issue with it, why do it?
Serpentine belt and hoses would be subject to the inspection. If you have about 100,000 on the belt, now it would be good time to change it. I had very bad weekend (!) on my vacations when belt broke and huge dealership back East didn't stock replacement.
10 years old hoses would qualify for replacement. At lest the lower one.
 

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Hey, Drew. Assuming the plan is to keep the car instead of fixing this and selling right away, my sense on these sorts of questions usually incorporates a repetitive work factor. If you don't change the part in question, will you have to redo some of what you already did? Or will the failure cost you some part of what you already did?

Were I changing the WP I would also be draining the engine and radiator and coolant tank so I'd be starting off with fresh coolant and distilled water. Since a blown hose would ruin that for me I'd be replacing all of them. A little extra work and some extra money now, but sooner or later they will fail, this way you take them out of the equation. And you won't be kicking yourself in 8 months because you're parked on the side of the road with no coolant from a blown hose.

The thermostat is a bit tougher. I have yet to hear of one failing in a benz, and if you watch your temp guage you'd have fair warning (of course it could still strand you). Since you have a fan you'll have to remove that would make the stat an easier job while you are there; I think I'd be tempted to do that. But I wouldn't raise my eyebrows at anyone for not doing it if you get my drift.

The belt is an easy one. If you're near or over 60,000 miles on the one on there then change it and keep the old one in the well of the spare as am emergency replacement. These are pretty cheap online and when they go they go all at once and you are parked. Kajtek's vacation story is a perfect example.

Remember to photo doc it all with a write-up for your constituents! (sorry, couldn't resist a little political humor...)

Take care and enjoy the ride,
Greg
 

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If I've caught you in time, make sure you have all the right tools! I spent an extra hour or two ***** looking for the short torx bit to fit the water pump bolts. Not to mention that the whole procedure was messy! Give yourself ample time, and an extra hand to help grab a tool from time to time and to keep you company. Good luck
 

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Discussion Starter #5
Yes I was looking at the All Data and saw that they had a special tool to hold the fan pulley. Do I need to use that or can I use something else to remove the fan. It looks like I can not remvove the fan shroud without removing the fan first. Was that everyone's experience?

I will definitely replace the Serpentine belt. The hoses look ok, still very supple. No signs of dryness or cracking. How did you guys drain the engine coolant?
 

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I dont remember getting hung up on the fan. The only problem I had was getting my hands down in the tight spots, and draining all the fluids without spilling everywhere. If you are a do it yourself kind of guy, you can do it. Just try to get someone to help cause it will make things so much easier!
 
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