300E leaking coolant near water pump

mike690003 · #1 08-02-2003, 08:16 PM

Hello board, My 1987 300E is leaking a stream of coolant near the water pump, the water pump has only been on my car for about 6 months. I thoroughly inspected the water pump and the leak isnt coming from the water pump. Could there be a freeze plug besides the water pump that the coolant could be leaking out of? If so is replacing the freeze plug a simple DIY, will I have to remove the water pump to replace this freeze plug? Could there be any other culprits causing this leak? I also thoroughly inspected the hoses and there isnt any leak, only the area near the water pump.

HELP!!!

sixto · #2 08-02-2003, 09:04 PM

Reach under the water pump and feel the weep hole. It's about at the 7 o'clock position looking into the pulley. If it's wet, it's the water pump. There's an o-ring between the water pump and block that might be leaking. There's also a back cover of the water pump that can leak. Are you sure it's not the heater hose that goes into the side of the thermostat housing?

I don't think there's a freeze plug anywhere near the water pump. Check out the pics at photos.yahoo.com/tabijan in the 91 300SE water pump album. Might give you some insight.

Check the archives also. Within the last couple of months someone posted about replacing a freeze plug for $70. Might be the same problem as you're having.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

mike690003 · #3 08-03-2003, 07:08 PM

Hello board, I did a thorough examination of the area and I see that the leak is coming from the area where the water pump is attached to the engine block. Do I have to remove the water pump and then add a gasket type sealant to the area?

sixto · #4 08-03-2003, 07:43 PM

There's an o-ring between the water pump and the block. It's less than $2.50 from the dealer if you can't wait for FastLane. I used a dab of sealant to keep the o-ring in place while wiggling the water pump into place.

I dismissed the recommended Snap-on tool because I can get to the upper rear bolt with a 1/4" socket arrangement. However, I had to remove the dipstick to use the 1/4" socket arrangement and that allowed coolant to drain into the sump. If the Snap-On tool allows you to get to the rear upper bolt without removing the dipstick, then it's worth the money IMO.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

#5 08-04-2003, 07:30 AM

The FLXM 13 is difficult to find. I couldn't even buy one on the Snap On website, they were out of stock. Maybe they have some now. After going through this myself, I believe the tool is worth the $45 or so.

You can use grease to hold the o-ring in place while fitting the pump and starting a few bolts.

Good luck,

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