Need help with M103 water pump replacement
 

I need to replace the leaking water pump in my '88 260e.

Fastlane indicates that the early M103's require a 103 200 14 52 drain return line and 124 501 33 32 lower radiator hose. Does this mean the replacement water pump will not fit with the original parts?

Anyone know if the replacment pump is a direct fit or if updating is required? I'm willing to go to the dealer if need be for a direct fit.

Thanks,

John

Call Phil and ask.

Replacement is not that hard.

I'm pretty sure they both need to be changed out. The lower radiator hose for sure, the original will never meet. Less sure about the return line, but I'm pretty sure that one does too. Is this the first time the water pump's been replaced? If it's been done once already, it's highly likely the updated parts are already on the car.

wbain is my hero. Anyone who says that replacing a 103 water pump is easy is a really good tech! Also, he must own the SnapOn FLXM13 thin shaft flex socket that will ease this job quite a bit.

I find this job a little challenging. It's not impossible, just hard to get at the three bolts and getting the tensioner out of the way is a little extra work beyond that. I have read that the pump can be changed without removing or loosening the tensioner, but I couldn't figure out how to do it.

I would highly recommend that you change the short hose between water pump and thermostat housing (I think that's where it is) because it is difficult to change otherwise. That makes it a good investment of a few bucks IMHO.

Good luck,

Thank You, Thank You! :)

Actually, at the time, it was a PITA but as I got into it, it wasn't all that bad. Maybe it was the 35F January temps when I did it and I was numb.

I used a Sears 3/8" u-joint on the upper rear bolt and I bought that one back in the 70's. I broke the new 1/4" u-joint.

So, in review, drain coolant, remove serp. belt and tensioner, unbolt PS pump and move to the side. Undo the pump bolts and the old one comes out. Don;t forget the 'drain tube' or water heater return line. Get a new O-Ring for that.

Use grease to hold the large sealing O-Ring in the new water pump.

I took the radiator out, better ones than I don't need to.

I did something similar and used a u-joint with tape around it to get to the top bolt that is obstructed by the intake manifold. I have been told by more than one tech that if you use the FLXM13 you can get it without removing the tensioner, but I sure don't see how they can snake the pump out. The reason the FLXM13 is different is that it has a 1/4" shaft that allows the whole mess to gain access.

The flat rate techs often manage to do amazing things to save time though. If a flat rate tech could actually accomplish changing the pump as easy as the techs say, then they can manage to make about 3.5 hours pay for a one hour job.

Relative to water pump jobs on most other cars this is not a quick and easy operation.

Have a great day,

I did mine in January. I will agree, it wasn't easy (at least for me). It only took me 6 hours, but it was a painful 6 hours. I didn't have the snapon flex tool, but I did manage to do the job without removing the tensioner - don't ask me how because I really don't remember anymore as that was so long ago. That bolt Larry's talking about wasn't the problem for me - it was the lower "hex" bolt. There was just no way to squeeze a ratchet with an allen socket in that recess, unless you ground down the end of the allen socket. I ended up using the allen socket with the box end of a combo wrench wrapped around it for leverage.

I got that rubber hose Larry talks about from the dealer here. I think it cost me $16. The auto parts store where I got the pump had the same hose for $2.50, but since this is what I would call a "specialty part" and I was leery of being in the middle of the job and finding out it didn't fit, I sprung for the dealer part. If I had to do it again, I'd go with the $2.50 hose. But then again, we're only talking about saving $13.50 here - you're already saving a few hundred by doing the pump yourself.

I took the radiator out - it only takes about 5 minutes, no joking. Why risk a wrench slipping and putting a nice hole in the core? Besides, removing it allowed me to analyze and make sure it was in good condition. I was also able to see that mine was an "updated" radiator with the metal insert at the hose connections. Plus, with the radiator out you have a ton of room to maneuver.

I got to do mine twice. The new one I put in failed after about 3 months :( As they say: "sure its gurenteed, we'll give you another one."

Success: Water Pump Replacement
 

I replaced the water pump on my '88 260e last weekend and it went pretty smooth.

The bummer is that the leak was the 99 cent o-ring between the pump and the block. The tensioner and water pump seemed okay but I replaced them anyway since I already had the parts on hand.

I took off the tensioner to get at the rear bolts and laid the power steering pump aside to get the water pump out the front. It took about 2 hours to get the pump off and about 4 to get it back on. I mistakenly was trying to put the too-long pump for the dipstick tube into the upper rear mounting hole for the water pump and could not get it to go in all the way. I had to take the pump off and check the depth of the treaded hole before I realized that the bolt was too long. That mistake cost me about an hour.

I also did some snooping and cleaning while things were apart and cleaned and painted the tensioner Y bracket...things a mechanic would not have bothered with.