w123 water pump replacement: Remove Radiator?
 

Is it really nessesary to remove the radiator to replace the water pump (as described in Haynes manual)? Thanks in advance.

Absolutely not. But it's not a bad idea to place a piece of cardboard behind the radiator to protect it from "accidents."

No, it's not, but it does make the job of removing and replacing the water pump that much easier! ;)The Radiator is not that hard to remove really. It takes about 20 minutes!:D

More like ten minutes.

Tom W

Cold or hot Tom:)?

It is alot easier to do it with it out.

With any car that I've owned, the hardest part of a radiator R&R is the coolant R&R. Any time that you must drain the cooling system anyway, the radiator literally takes a few additional minutes to get out.

The radiator is really easy to remove but it would be advisable to only remove the hoses from engine and leave them attached to radiator. The radiator necks are brittle plastic and can break off easily. You don't want to have to replace the radiator for nothing.
Reinstalling the radiator can be a little more difficult if you remove it with out the oil cooler. The oil cooler clamps are a little difficult to line up especially the bottom one.

The easiest way I have replaced a water pump, is when I had the engine sitting on the ground looking at me. :D

seems to me if the plastic on the radiator is going to break just removing the hoses, maybe it was time for it to be replaced too. every so often it is recommended to replace the hoses, are those not going to be changed from fear of breaking the radiator?

removing the radiator will give more room to work. also a good time to blow out the radiator fins and ac condensor.

that lower oil cooler clamp can be a bugger to get back on. It`s just like the top one, just reversed.

Charlie ☺

The extra 10 min it will take will be more than made up for when replacing the pump.

If it's an automatic, it will also have two transmission cooler lines attached to it. Just so you don't snag on them. There are a total of 6 hoses attached to the radiator.

2 radiator hoses
2 trans cooler lines
2 expansion tank lines

Be careful with the top expansion tank line that enters sideways into the top of the radiator, that part breaks easily.

For what it's worth, the MB 617 Service Manual does not call for the removal of the radiator when replacing the water pump.

Yeah, I JUST noticed that minutes ago. It it really worth it for 2 inches of play room? It doesn't seem like it... Other than that, is this job as straightforward as it seems? Anything I need to watch out for?

2 belts, 4 fan bolts and 5 bolts on the pump. Thats all it is.

No.

Once you remove the fan and shroud, there is plenty of room to work, with the radiator in place.

That's what I wanted to hear. Thanks, all. As easy as it seems, maybe I'll do a writeup.

I forgot about all you poor saps with slushboxes. :D

The FSM assumes that every thing is in good shape and you don't bust a bolt off or something...

In my experience, the hoses last longer than the radiators. I wouldn't be durprised if 3/4 of all the hoses on my 123 cars are factory original. I don't change them if they are still good. I doubt that any replacements will be as good as the originals.

Tom W

My hoses appear original as well as the clamps. They all looked just fine.

Apply WD 40 or other to the bolts holding the pump in place a couple of times. Make sure the wrench is a good fit so as not to round the heads. Just remove the black plastic fan shroud then the fan to get easy access to the front of the pump. Easy on the bolts. Don't use a pump with a stamped metal impellar. Should be cast either in metal or plastic with a proper curves blades.

Why is this?

I am going to be tearing into the front of the motor tonight/tomorrow as it appears that is where the puddle in the driveway originated from.

I ordered a w/p gasket set from my auto parts store on the off chance its just a gasket issue and not an internal seal issue.

Water pump is simple, housing, bearing, impeller, and a seal. yes? I am hoping its just a gasket failure and not leaking around the shaft.

Does anyone know if there are more factory manuals available? or the same info on CD/DVD?

Thanks.

The cast metal is much stronger and lasts longer thant the stamped out sheet metal.

My rebuilt one from O'Reilly was the cast type.

Another point to make is there are 2 weep holes on these water pumps. One on the top and one on the bottom that you would likely never see or know was there without removing the pump.

I never heard of a weep hole up top. Wouldn't that let grit and other stuff in?

Can't confirm or deny. BUT, FWIW mine has a weep hole on top - the one that's one the car at time of this post. Not sure about the WP I just ordered from NAPA today (made by Gates) but I plan to pick it up tomorrow and then I'll know! :D

Its a dry galley so the hole on top is insignificant. What gets in can get out.