Water Pump Time!

[Richard Moakes]

Well, it looks like I need a new water pump , it's squealing and I am slowly losing coolant on the garage floor.

My question is as follows, what is the current part number for a M103 water pump? I think it is 103 200 37 01 , however EPC indicates the part that exactly matches my engine number (10398322136687) should have been 103 200 26 01, but this has been superceded !

Any parts experts out there willing to help validate the number before I order this expensive bit, or strip everything down and find it doesn't fit!

I have also ordered the Snap-On tool FLXM13, so hopefully this will be a bit easier than the M104 pump I did a couple of months back.

Thanks,

Richard

1989 W124 300E

 

[Andy]

Hi Richard

Can't validate the part number. But if they have checked the part number thoroughly then you should be ok. If its incorrectly supplied they will have it back. Don't fit a none genuine. If there is a problem the pumps don't just fall off. You will find the 103 pump a little tighter than the 104. If the snap on tool is a flexi 13mm socket. Then you will need a 6mm allen key socket as well. If I were you I would replace with a 13mm bolt when you refit the pump. You will see what I mean when you do the job. As one last bit of advice. When you get the pump make sure all the holes are where they should be and non over before you fit. Ie the sender holes etc.


Good luck

Andy @ www.mercedesservicing.com

 

[dave e]

Richard.

I did this job only a few months ago, lets just say that it's not difficult, but not easy

When i read the Haynes manual it doesn't mention removing the radiator!! unless i misread it, I did remove it and can assure you it made the job a whole lot easier.

I have various Allen key sockets, which were essential when removing the bolts that secure the pump to the block, however 2 of the bolts are not asseable with anything other than an Allen key, but again i scored here, as i had a Snap on Allen key that has a short throw, ie. long handle, short bent bit, (please don't think thats condescending), this tool got the other bolts out. It was all a piece of cake from there on...........LOL

After i got it back together i posted on here about it, and Andy picked up on the thread and recommended replacing the Alen bolts with 13mm bolts, well i have only one comment to make on that,...........why didn't i think of it??? it would certainly have made life easier.

Good luck.

 

[Richard Moakes]

Hi Dave,

Thanks for the info, I had some similar problems with the M104 water pump I changed for my father about 3 months ago. I didn't remove the radiator, but removed the fan shroud, various pulleys and the belt tensioner.

Why did you remove the radiator? Most of the access needs to be from the side of the engine and from above, not from the front. You must know something I don't about this job on a M103 ?

I have some Snap-On 3/8 drive allen keys, and also some Halfords pro 1/4 drive allen keys, which combined with numerous extensions and flexi handle ratchets enabled me to remove the four allen head bolts holding the pump to the block.

In this case, it seems there is a mixture of these allen bolts and normal 13mm hex head. So reading up on the US forums, it seems that the Snap-On FLXM13 is the tool for the job, and at £50 it will save a lot of cursing and scraped knuckles.

Did you drop the aircon pump, as per the MBUSA manuals? On the M104 it was possible to 'roll' the water pump out after loosening off the tandem pump. I am worried that on my car the CIS inlet manifold is going to get in the way compared to the LH on my fathers car.

Any more insights into this gratefully received, I will share my experiences with you and others when I have completed the job.

Cheers,

Richard

 

[Richard Moakes]

Well, it's done, it wasn't too bad, but I don't want to have to do that job again!

I didn't remove the fan blades, just the shroud, then removed the tensioner mechanism and rolled the power steering pump over to the n/s.

After that, it's the joy of the four 13mm bolts holding the water pump to the block, I can definitely say that Snap-On FLXM13 is worth it's weight in gold for this job, made it so much easier to get them loose.

Oh, always check the pump supplied has all the o-rings in the box, mine didn't have the seal to the block, which is the second time this has happened to me, last time being a M104 water pump. Thankfully I noticed this when picking up the pump and got a genuine o-ring from the dealer.

A bit of instant gasket later, lots of re-assembly and skinned knuckles, and a slight leak from the thermostat housing which delayed me for an hour, it was all back to together.

I wouldn't recommend this job unless you have an extensive selection of tools, sockets, spanners etc..., and have already done some major surgery on an engine before.

I now have even more admiration for guys like Andy who do this sort of thing all the time. Don't argue what it's going to cost, just pay them and be grateful they are cheaper than the stealerships!

Cheers,

Richard
1989 W124 300E