Waterpump leaking?: M103 engine

[Ron in SC]

I have coolant leaking down the oil pan on M103 engine in vicinity of oil drain plug.

I can not see the weep hole on the waterpump. I am assuming the coolant pump is leaking.

Is the coolant leak I describe the sympton of a coolant pump leaking from the weep hole?

[Ivanerrol]

I have posted this response twice in the last week

Did this job myself last week on my W124 M103 260e. Water pump was O.K. just a leak from the bottom.
What a barsteward of a job to replace a $ 3.00 O ring. The Aircon hoses are in the way of the rear bolts of the pump.
While removing the components to get at the pump I rocked the water pump pulley back and forwards to determine whether or not the pump front bearing was O.K. The rocking backwards and forwards of the pump exacerbated the O ring leak and it was quite easy to see coolant dripping out from the bottom area of the pump and not the bearing assemblies. The rubber O ring between block and pump body flat, hard and leaking


Items removed to facilitate job: Fan shroud, fan and clutch, fan and power steering pulleys, Dipstick and tube removed, belt tensioner, power steering moved out of the way, removed distributor to get at bolt holding heating tube to block, first two injectors and lines, moved IACV out of the way, radiator hoses.
Time taken to complete entire job 8 hours - including time to look for dropped bolts hidden in inaccessible locations

New items: O ring for pump body, O ring for heater tube, new bypass hose between block and thermostat housing, lower radiator hose.

Ivanerrol recommends purchasing a flexible extension - extremely handy.

[Ron in SC]

8 hours - including time to look for dropped bolts hidden in inaccessible locations

I'm a member of that team.

Helpful and interesting reply. I will try to inspect the location where the coolant is leaking from tomorrow.

Once you had the whole thing apart did you consider replacing pump due to the labor involved?

[Ivanerrol]

Pump was O.K. and had already been replaced previously by P.O. My car has only done 150Ks (kilometers - 100K miles)

Next time I need to do this job, I estimate it to take less than 4 hours.

The real pain is that less than two months ago I replaced the belt tensioner. I should have done this job then. However two months ago we weren't getting 118 degree F days or three days in a row over 110 degree F in Melbourne Australia

If your pump is suss I would replace it.

[Cal Learner]

Ivanerrol, Nice sanitary looking engine & bay. Looks like someone else is as obsessive as I am. Is that your doing, or did the PO keep after it? Only thing left is to powder coat the valve cover next time it's off. Sweet!

[S-Class Guru]

Ron, you can buy a small inspection mirror on a telescoping handle and check the weep hole.
But, actually it doesn't matter, the pump has to come off either way. When you get it off you will easily tell if coolant has been leaking out the weep hole - it leaves plenty of residue.
I'm on my 4th water pump on my 300SE (18 years) and I managed to replace it last month removing only the pulleys and the tensioner, and rotating the steering pump a bit. But it's pretty tough to get those rear bolts.

DG

[Hirnbeiss]

Originally Posted by Cal Learner

Ivanerrol, Nice sanitary looking engine & bay. Looks like someone else is as obsessive as I am. Is that your doing, or did the PO keep after it? Only thing left is to powder coat the valve cover next time it's off. Sweet!

Agree, but the coolant areas look a lot more corroded than I would expect using the right coolant and water ratio. Could that be?

[ps2cho]

^inside of the block looks great

[Ron in SC]

^inside of the block looks great

Thanks. This motor has been very well cared for. It's such a good motor, that when my 1992 300E was hit from behind and totaled I removed the engine and transmission as a unit and put them in my 1992 300TE. The motor and transmission have only been in the wagon about 3 or 4 months.

I put a new front crankshaft seal in the motor earlier this week.

[Camohall]

compartment looks great!
How on earth did you get the tensior and pump out without touching the ps pump?
I'm trying to do it myself right now...have the same problem.
can't seem to break the pulley bolts. advice?
well done.
cam

[Ron in SC]

How on earth did you get the tensior and pump out without touching the ps pump

I moved the power steering pump out of the way.

I posted some instructions for you in the thread you started.

[Tassie]

I have another question on this.

I have a coolant leak in the same area so I am presuming the water pump or water pump gasket is leaking. I pressure tested the cooling system and found a minor leak at one of the rad hoses. Tightened the clamp and the pressure test held. Next morning I found more coolant (but not a lot) on the ground. A closer inspection shows coolant on the block under the pump but I could not get any closer to discern the source of the leak. There is no noise from the pump so I am presuming a gasket leak.

My question is: Is this an immediate repair? Am I playing with fire by deferring the leak repair? The car has 120,000 miles on the original water pump. Should I go ahead with a new pump if I have to pull the pump to fix the leak?

Thanks in advance for your advice.

Regards...

[pawoSD]

I would for sure replace the pump at 120k. No question about it.

[Hirnbeiss]

the leak is probably from the weep hole under the pump shaft.

[AtlBenz]

ohhh boy. I guess i need to join the club. my hands are black as night typing this post, but yeah, I jumped online to see what the deal was with this leak. looks like everything has to come out. no magic trick eh? just remove the entire front left area of the motor. great. well back to work.

This is on a 95 e320 wagon btw, in case anybody comes up with something.