I've read many posts on the subject, but where exactly is the water pump located? I found a small puddle of coolant under the brake master cylinder, and a small amount on the garage floor (behind the left front wheel well). Is this in fact the pump, or could it be a hose? It appears that removing the pump is a difficult job. Is it very expensive to have it done? I would appreciate some advice. Thanks!

Brian

The water pump on that car is located on the front of the engine , drivers side . If it leaks it will run down the oil pan by the oil level sensor. You might check your heater hoses in the area you are talking about.

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euro 287
Mercedes Technician 7 Years (retired to Hyundai)
2000 Dodge Durango
98 Mazda truck

that goes from the fire wall (by the master cylinder) behind the air cleaner assembly and connects to the rear of the engine.
Are you sure it is coolant?

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J.H.
'86 300E

might also be one of the heater hoses leading to / from the duo / mono valve, or even the valve itself. The area drains to the rear of the front wheel ...

L

Yes it is definitely coolant. However, that particular hose (line) is metal, and the black foam wrapping was damp. Could this be an easy fix, or does it indicate a larger problem?


Brian

Yesterday, there was also a small amount of collant right behind the left front wheel, so I am inclined to believe that this may be the problem. What is involved with replacing these hoses, or the valve?

Brian

I am confused now.
In your last two posts, are you referering to the driver's side or the passenger side?
The monovalve is on the passenger's side. If itis the driver's side, there is an A/C metal line wapped in foam in that area that CAN get damp, which is normal. Which side is it?

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J.H.
'86 300E

Sorry for the confusion. The coolant is on the drivers side near the master cylinder. There is also some on the garage floor behind the drivers side front wheel. The AC is not working (at least it does not blow cool air). I am not seeing any other obvious coolant leaks, so I am wondering where this leak may be coming from. Any help would be greatly appreciated.


Brian

if your actual heater, inside the dash, is leaking. The "condensation" outlets from the A/C evaporator come out in the transmisssion tunnel, on each side of the transmission. That is consider normal but since your A/C is not working...
NAPA sells a fluorescent dye that can be trace with a black light. They are cheap and easy to use. Just pour the dye in the coolant, drive for a while and then check the engine bay and underside with the black light. That would also tell you if it is 100% coolant.

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J.H.
'86 300E

Thanks! I will try the dye test. However, if the heater was leaking in the dash, wouldn't there be some indication of coolant on the floor inside the car?

Brian

If it's on the passenger side then it's probably the aux water pump. Mine went out and started leaking bad. At first it was small leaks, in the end was adding water and coolant evertime I drove. The part, which could not be located at any local parts store, is availible through our host for around $100. It took me 5 mins to put it on. I'd look for the cause of the leak first before making assumptions about what might be causing it. Good luck.

It would not show inside the car because there are foam hoses from the heateer box to the outside. Sometimes those hoses will go bad and then the water would be seen inside. Your description of the problem is different. Try the dye test and let us know what happen, unless somebody has a better suggestion.

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J.H.
'86 300E

I found the leak! It is in fact coming from the metal line extending from the dash, but it is leaking right past the connection between the metal line and rubber hose. Luckily it is the rubber hose that has the small pin hole. I noticed this hose runs under the engine block towards the passenger side. What is the name of this hose, and how difficult is it to replace? Please advise. Thanks!


Brian

I think you are talking about the heater return line. Easy to replace. Remove the air cleaner assembly and you would be able to see it better. I would suggest to get a new hose and new metal clamps. Then do a coolant change at the same time, since you are going to drain the coolant anyways. The whole repair should cost less than $40.00.
Good luck!

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J.H.
'86 300E

HELP ME! My 1989 300E has a coolant leak and I can't find it. It's dripping between the driver's side engine block, towards the front of the engine, and the A/C compressor area. I don't think it's the waterpump, I checked that and it is dry. Are there any hoses or anything on the driver's side engine block at the front of the engine.

THANKS!