Replacing water pump for the first time - PeachParts Mercedes-Benz Forum

SSharma · #1 05-22-2002, 06:31 PM

Hi all. I'll be replacing the water pump on my 84 300TDT, following the instructions in the Haynes manual. I assume those are complete directions. Anything else I can/should do while doing this? I've been reading old posts about water pump replacement and it seems that it's not necessary to take out the radiator (I may go ahead though so I can clean everything more thoroughly). Any other tips? Thanks a lot

#2 05-22-2002, 07:20 PM

You will probably need to grind down a box end 10mm wrench to get to the fan blade bolts, that's what I did. Other than that, its really easy on the 617 engine.

engatwork · #3 05-22-2002, 07:37 PM

if you do end up removing the housing go ahead and take the opportunity to replace the short piece of hose at the bottom of the housing. Easy to replace when you are in there.

#4 05-23-2002, 07:41 AM

You have already recieved some great advice. The only thing I would say is that the radiator is so easy to remove that, if it were me, I would go ahead and get it out of the way.

I might not do this on the four cylinder, but that extra cylinder limits the room you have to work with.

My $0.02,

SSharma · #5 05-23-2002, 12:19 PM

Thanks all. What is that short hose called? I might order one and replace it (if it looks like it needs replacing).

#6 05-23-2002, 03:07 PM

I suggest you replace all the hoses while you are in there and I second LarryBible's advice that you go ahead and remove the radiator. To do so you must disconnect the transmission cooler hoses but thats easy and it gives you the opportunity to renew them with newer versions that have wire wraps for protection. A little fluid will escape but not much.

I just took that small hose to the car parts place and they matched it with one I could cut a section out of.

Nic
'85 300CD

SSharma · #7 05-28-2002, 03:42 PM

Ran into a small problem, can someone help me out? Step 4 of the Haynes Manual says "remove the upper and lower pulleys and the engine drivebelts". While this is pretty straight forward, it does seem to leave out vital information - how to remove that stuff, and what tension is required when replacing the belts. Does anyone know how to remove the pulleys and belts? Thanks.
[Edit: Also, should I put anti seize on all the bolts when replacing them?]

#8 05-28-2002, 03:47 PM

If I remember correctly, two different belts go on the water pump/fan pulley. You must loosen the alternator and the power steering pump to get them off.

To loosen the alternator, get under the car and loosen a 14 or 15mm pivot bolt on the bottom, then under the hood is a 13mm adjust screw that you wind out, and allows the alternator to pivot back to loosen the tension.

The power steering pump, also loosen a pivot bolt, and then you have a 10 or 13mm adjustment screw that you wind out to loosen the pump.

SSharma · #9 06-13-2002, 11:45 AM

Still working on this...thank god my dad's retired.
I took off the rad and the water pump housing when I replaced the pump. I put everything back and fired the car up to see if it worked. When I revved it, coolant started pouring out the bottom of the housing. Did I just not tighten everything down enough? Or do I need some kind of sealer between the housing and the block? I also don't have a gauge for the tension on the belts, how important is that?

As an aside, I decided I would clean the engine bay while I was at it because my throttle linkage was sticking a little. No big deal, just idled a little high. Now I can't shut the car off. I have to rev it and then push that thing on the throttle linkage to shut it. Can I take each piece of the linkage off, clean it, and regrease it (what kind of grease)?
Thanks

engatwork · #10 06-13-2002, 12:05 PM

You probably knocked a vacuum line off to cause the "won't shut down" condition that has arisen.
Did you replace the lower coolant hose? Is it tight? Isn't there an o-ring on the wp housing nipple that seals the block/housing interface? Seems to be a memory cell in there somewhere where a light goes off with this thought.

SSharma · #11 06-13-2002, 12:47 PM

Which one/where is the lower coolant hose? Any tips on how to find a knocked off vacuum line? I didn't notice an O-ring, so I don't know if one's supposed to be there. The Haynes manual didn't mention it, but it wouldn't be surprising if they just left it out. Also, mine's a Euro spec, if that makes a difference.

MVK · #12 06-13-2002, 08:56 PM

I cant believe you took apart everything and also under took a task of changing the water pump and now you you are asking which one is the bottom coolant hose.
I hope you are not kidding us. - Just like that kid the other day on this forum.

Anyway for your future projects no matter how good your memory is , draw a rough diagram of locations of each tube and hoses. That way you are not lost when putting things back. Also from my experience of changing a carburator in 1985 oldsmobile, I can tell yoy that taking a video clip of all attachments etc before and while you are taking aparts things is very very helpful.
Dont get me wrong I think most of us have been there. I am also not challenging you ability or memory. This is just a little thing that my brother told me when we used to fix his scooter and motorcycles years back.

MVK

SSharma · #13 06-14-2002, 11:06 AM

Well, what I thought was the lower coolant hose, I didn't have to take off. I also didn't have to remove the power steering belt. Differences with Euros I guess. I thought maybe 'lower coolant hose' might refer to that tiny 2 inch line right above the water pump, or that short, fat hose that connects the pump housing to the thermostat (although neither of those is really 'lower').
I went over everything again and it looks like I put everything back right.
My concern is the belt tension, or if I missed an O-ring or something between the housing and engine. For the belt tension I did what the Haynes said, pushed down on the center and then tightened til there was only 1/4" of play. On the O-ring, I didn't see one there to replace, but maybe it fell off. Hopefully the rain will hold off today so I can go tighten down the housing bolts and see if that was all I needed.
Thanks for the idea about the diagrams, that's a good idea, and easily done.

william rogers · #14 06-15-2002, 12:16 PM

Amen! on changing all the hoses even if they look good ,new quailty hose clamps too, all for the price of a night out at Burger King.......
William Rogers......

JimSmith · #15 06-15-2002, 04:04 PM

SSharma,

Just curious, how is the job going? I would expect there to be a gasket or an O-ring seal between the water pump housing and the block. There is definitely one (a flat, heavy paper like like gasket) between the housing and the pump flange. You have to make sure these sealing surfaces are clean and free of gouges or heavy scratches or they will generally not seal. A while back there was a huge debate on whether or not to use a gasket sealer when doing this job, and the consensus was it should not be required but many use one anyway. A thin film between the gasket and the housing as well as the pump flange will help seal any scratches and pitting that may exist. It is unlikely it will help if you have a really deep gouge, or raised metal at the edges of the defect. You need to smooth them off with a light, fine grit abrasive first, then use the gasket sealant.

Good luck, Jim