M103 water pump failure ?
 

Before I start tearing it apart ,I was wondering if the leaking pump would drip coolant down to the oil pan (near the drain plug) or would it drip from the front of the pump . I've cleaned the engine and can find no evidence untill it runs down the side of the oil pan. Anyone else run into this before?

There is a vent hole under the snout of the pump. The leak will come from there. It is about impossible to see this hole in the installed position so area is the main determinant. There have been tubes placed on some pumps that take the fluid to the drivers side behind the compressor, but usually the coolant drops from the front of the motor. Check also the hose to the head although you about have to remove the pump to get to it anyway.

Thanks Steve , I took a look under the snout (near the pulley)with a mirror and can't see a hole or any leaking in that area, the head to t'stat hose is ok also. Could the O-ring between the pump and crankcase fail and leak in this area ? I can't see a tube from the front of the pump to the rear, is it cast into the pump? Thanks in advance , Kyle.

The o-ring between the pump and block sure can cause the leak. If the history of the waterpump is not known or if it's over 3 or 4 years old (with a normal amount of mileage in that time frame), I'd say it would be "false economy" to just replace the o-ring seal. I'd replace the pump, since you'll need to completely remove the pump to replace the seal. The new/reman pump will come with the o-ring seal.

Gilly

Thanks Gilly , I'll start into it tonight:rolleyes: ,and order the parts tomorrow.

I went through this about 2 months ago on my '88 103 engine. That pump went about 240,000 miles. It started leaking all of a sudden. It was dribbling from the pan rail just behind the a/c compressor. It was also dribbling on the sway bar.

As Steve said, it's virtually impossible to see the weep hole. It is almost as seemingly impossible to replace the pump. I had recently bought a 1/4" drive mini air ratchet. It sure was handy for running a few of the difficult to reach bolts. I did not have the special Snap On FLXM13 universal joint that allows you to replace the pump without getting the tensioner and power steering pump out of the way.

I checked on the Snap On site and they were out of stock. If I had it to do over again and I could get the Snap On tool, I would have paid the $48 or so for it even though money is very tight for me right now.

Put grease on the o-ring to keep it in place in the pump while putting the pump in position.

Good luck,

Larry
You can always try searching out your local Snap-On distributor (tool truck guy, check the white pages and yellow pages or ask at a local garage for the phone number of their Snap-On man).
It's possible the local truck guy might have it in stock on the truck, even though the warehouse is out of stock.
Not every area has a local distributor, but it doesn't hurt to look.

Gilly

I also think the Snap on tool ($48) would be well worth it. I just replaced the pump on my 1993 300E, and the tool would have been a life saver. Be careful about frozen bolts if the pump is original. One of the 4 bolts on my pump was stuck, and had to be sawed off (the threads were fine, it was the bolt head that was basically welded to the pump housing).....

Kyle, my 104 engine was seeping coolant down the block in the same area as yours. But it would only leak when the engine cooled down. Maybe a day an ahalf later. White streaks down the block and oil pan. My INDY took a pressure test and it showed no leakage. I was possitive it was the o-ring to the water pump, he could not be sure about it. With a small mirror I could see that weep hole on the pump and it was dry. It had to be the o-ring to the block and pump. It was that o-ring, and I replaced the pump since I was there. Not an easy job on the 1990 300CE, it was a rotten job. Good Luck

Thanks for the response guys, I used a universal joint with a socket taped to it , and various extensions to get at the 2 rear bolts. Definitely challenging to get at :rolleyes: but nothing compared to the time I've wasted trying to remove the center fan bolt . I think a previous mechanic ( and I use that term very loosely ) welded the thing in place . It's still in there , but I won't be defeated . BTW , the pump was dripping at the weep hole as well as around the O-ring .

Why were you removing the center fan bolt to change the water pump?

BTW Snap On now has the FLXM13 in stock and available online.

Have a great day,

Larry:
He's want to take off the fan bolt for this disassembly procedure, which i guess isn't neccesary if you have a good tool to remove all the waterpump bolts:
Remove shroud and fan
Remove serp belt
Remove pulley from fan hub, water pump, and power steering pump
Remove belt tightener, incl tightener bracket
Remove remaining bolt holding power steering pump to accessory bracket (the other bolts were removed when the tightener bracket was removed)
Loosen bypass hose clamps and procede with removing waterpump bolts.
In a nutshell, that's how the pump would need to come off unless you can access the waterpump bolts without removing anything.

Gilly

Those are exactly the steps I went through Gilly, EXCEPT the fan bolt (I give up , for now). I managed to loosen the 1 bolt that's behind the fan pulley enough to move the tensioner bracket out the way. Larry , I needed to replace my tensioner and shock absorber also , but without that Snap-on tool it would be impossible to do without at least pivoting the P.S. pump out of the way.I finally got it back on the road tonight , after about 6 hours in the evenings this week. I figure the only way that fan bolt will come out is if I pull the rad (again),condensor and auxillary fan and drill the bolt out , then use an easy-out :rolleyes: .I think I may have bent it a tad with all my efforts , so a new fan assembly is probably in my future.Thanks for all the response , it's very appreciated :cool: .

Kyle:

I'm sure you know by now there's a special Stahlwille 8mm allen head type socket used to remove the fan bolt. I found that it also helps to have a LONG 3/8" breaker bar and just the socket to get the bolt loose.

The area on this bolt that the 8mm allen head goes into is made of very soft metal and it rounds off easily. I suspect a heavy-handed person paid it a visit some time in the past.

I went thru the same thing a few years ago and managed to use a pipe plug socket(male) to get the bolt out. SK makes these sockets. The bolt had been round off so I used one of these square pipe plug sockets. This is one of those times when a "square peg in a round hole" might work. I did for me.

Here's what they look like - 3/8s and 1/2 in. drive.

http://www.mytoolstore.com/sk/sk03221.html

If you can get a little extra clearance, possibly by removing just the radiator, I've had good luck getting out a rounded fan bolt with a Torx socket, and that was with the allen pretty well dug out already by the slipping allen tool. Just a few careful raps with a hammer will seat in the Torx bit, and it has always worked for me. You should also have the tool to lock the fan pulley in place, I assume you are using the lock tool.

I believe the Torx size I use is a T45

Gilly