Stats: 1987 260E M103 2.6L engine.

Hello all, I am trying to fix a coolant leak that gives me the warning low coolant lights. I think the leak is from the water pump vicinity because I see the fluid sprayed at the top of the cylinder collected in little crevices near the pump etc. At first I thought its the water pump. However I took a closer look and saw a brass pipe (Water Pump Drain Tube) coming out of the water pump that is already badly corroded at the location where it bolts onto the water pump. I am suspicious that the water start spraying out this corroded section at highway driving speeds, and drains the coolant. So I am going to try replacing this tube first and hope to avoid replacing the water pump as it is a big bad job.

I have on hand a Water Pump Drain Tube, however it appears to come with out as gasket. My question is does it requires a gasket? where it bolts onto the water pump? Should I go back to the dealer and buy a gasket for it? Thanks!

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the drain tube is there only to let you know the water pump is leaking. good luck, chuck.

How does it work exactly? If the pump is leaking, the drain tube will pass coolant from the pump over to the reservoir?

have an "O" ring.

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J.H.
'86 300E

throne7, the part you're describing is the heater return pipe. As mentioned, install a new O-ring when you install the replacement pipe.

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Fred Hoelzle

Hello Everybody,

I am initiating the fixing of the coolant leak. I got my tools together and went to the car. I started the car and immediately I see a spot of green coolant drops onto the area just below the thermostat housing on the pump (see photo). So I am pretty much sure that the pump is leaking.

I wanted to start removing the fan blade but notice there is a piece of plastic surrounding it (I guess we call it Fan Shroud here right?). I tried to remove it but the fan blade is in the way, and I am not sure how I can remove it.

One other thing, after reading posts from here, I went and bought a Snapon FLXM13 tool hoping it will help me remove the 2 rear bolts on the water pump. But guess what? It might be useless. I looked at the visible front bolt on the pump (see photo) and saw that it is not a normal hex nut type bolt, but the reverse type where the hex shape is inside. See second photo. Since this unpleasant surprise is thrown at me, how can I modify the FLXM13 in order to use it? Not a nice situation at all.

Thanks in advance for any help.

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car stats: 1987 260E 2.6L M103

By the way, how do I work the tensioner on the M103? I know that once the fan blade is out, I must work the tensioner in order to remove the belt and get at the pump. Are there any diagrams on how this tensioner works? Thanks!

Or put the SO tool for sale here or on flea bay and buy yourself an Allen set.

You want the inside of that Inset Allen Head CLEAN ! AND make sure the Allen
Wrench is fitted COMPLETELY into the inset.

Factory Service Manual (on CD) ordered from local dealer.

Somebody here knows how to access it online.....

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'84 300SD sold
124.128

To loosen the tensioner you need ideally to remove the fan shroud and viscous clutch and fan.
There is a 19mm bolt located between the water pump and power steering pump pulley. This must be loosened. After loosening use a 13mm socket and extension to loosen the tensioner arm. You can then remove the serpentine belt.
You may need to remove the tensioner completely to remove the bottom front water pump bolt. You will also be required to loosen the power steering pump to get access to the rear water pump bolts.
The top front water pump bolt has a allen key head - as in your diagram.

I removed the radiator from my 190e 2.6 to facilitate access. As you realise there is not a great amount of room at the front between the engine and radiator. You can also remove the distributor cap - it makes the job easier also.

There is a DIY sticky on this job in the DIY section. It relates to a w124 but basically is the same job.

Here is a picture of my 260e half way through replacing the water pump.
Note what I removed to facilitate the job. Other more experienced hands don't need to remove this amount of equipment however for the shade tree mechanic it makes the job easier. Note that this is a w124 so more room and i didn't remove the radiator.

Here's some more fotos of a 190e 2.6 Note there's not much room.
The first shows the position of the 19mm bolt required to be loosened on the tensioner


Nest sows the tensioner adjuster. Loosen this and the belt can be removed

Thanks Ivanerrol. Is there any trick to remove the fan shroud. I tried to last night but it seems the thing is prevented from moving out by the fan blade. Its has the round hole that circumscribe the fan blade and I guess channels the air across the radiator. This piece of plastic is right between the radiator and the fan blade. I don't see how it can be removed, unless I have to remove the radiator first.

[QUOTE=Ivanerrol;2158593]To loosen the tensioner you need ideally to remove the fan shroud and viscous clutch and fan.

Sorry missed your car type. Got confused with 190e 2.6
There are two clips either side of the radiator you must remove.
You can then pull the fan shroud up over the fan. Access to the fan clutch is then easier. You use an allen key and extension plus a tool to hold the fan .

See this thread

http://www.peachparts.com/shopforum/showthread.php?t=248249&page=2

I had no luck remove the fan blade today. I detach the shroud from the radiator and push it back towards the engine block. Then with the little space between the rad and the fan blade I first tried to unscrew the middle bolt (hex) but it just keep turning and turning but wont' come off. I guess its rust in? Mind you I was doing this by holding the fan blade with the other hand so it won't spin. I was not able to push a pin throught he hole from the other side to lock the fan blade as the othre thread suggested. The reason is I can't find that lock hole at all.

Next I tried to unscrew three screws that attach the blade to the clutch, but one of them is so rusted that the allen key just torn the thread and that last screw wont' come out.

So now I guess my only option left is to remove the radiator.

Here are some more fotos that may help you.

The fan clutch is attached to this assembly



There is a notch in the side see next foto



You need to make your self a tool from quarter inch rod and bend it slightly at the end. You need to insert it into the notch and in one of the holes in the pulley as shown


Once this tool is in place you then start to remove the fan clutch with the allen key and assembly (anticlockwise.)



You can see that this is a w124 260e. There is a suitable amount of room between the radiator and the fan clutch. However if the bolts are frozen on you may have no alternative than to remove the radiator. This is not
a difficult job either. If you remove it make sure you give it a good fluch out.

Here is a foto of what needs to be removed to get at the tensioner.
Fan shroud
Fan clutch
Serpentine belt
Fan clutch pulley
Power steering pulley
Water pump pulley
Remove 19mm bolt from tensioner
Remove Y shaped bracket.
Loosen power steering pump



Note that the fan pulley has 4 bolts in it.
The power steering and water pump pulleys are the same and are held on by three bolts.
Its better to leave the serpentine belt on and tight to be able to loosen the bolts in the pulleys easier.
Its easier to remove the fan attached to the fan clutch if you have difficulty with the bolts holding the fan
to the clutch.

Make sure you have the right tools for the job. Get a set of allen keys

Here is some more info on the tensioner. You can see from the fotos that you need to remove the water pump pulley to get at the 19mm bolt



To remove the Y bracket the fan and power steering pulleys must be removed. Don't forget you need to remove the tensioner shocker also.



Here is a foto of the tensioner removed. See that bolt at the bottom of the water pump? Very hard to get to with the tensioner in the way.



I can get to this stage from start in about 45 minutes.