Replacement Water Pump issues

[noctua]

So I had a leak and from the staining, it looked like it came from the water pump. Old car, same issues.

I went to the reputable parts supplier to get the parts and was told that they did not carry the original BMW E30 water pump but offered an OEM. I didn't have a choice so I took it.

The process of replacing the water pump was relatively painless and credit to the mechanic, he made sure that there were no other leaks (from observing the water jackets, plug etc where water would go).

When we started up the new water pump after putting in fresh coolant (BMW coolant), it started to leak again. Though it wasn't as heavy a leak as before, it nonetheless leaked.

We traced back to the leak to the water pump. That's right, the water pump.

So we took the car apart again and examine the area around the water pump housing; no staining, no cracks.

We spent almost 2 hours going through the entire engine block for signs; no cracks.

Finally, we measured the hole of the housing, the water pump cover and the gap between the moving part and the water pump cover.

The water pump covering area was smaller in diameter than the housing, and by like 1mm or less (calipers to measure).

The gasket provided by the OEM was also too thin to provide sufficient coverage; so they had to use a thicker gasket and ensure that the covering area was totally putty up properly and put the pump back in.

I am still monitoring today.

Just wanted to tell fellow E30 drivers here (if any left) that you might encounter this if you use this replacement part which was marketed to me as an OEM (it is not apparently, Saleri is the OEM based on Pelican), that you might encounter the same problem and the simple fix to ensure no leakage (or minimal).

The brand of water pump I bought was KWP.

 

[pings]

Re: Replacement Water Pump issues

Hi Noctua - another E30 driver here,

Am a new member here - own a 1991 E30 since the last few months. I recently had the timing belt renewed along with the same KWP Water pump - no issues with fitting.

Engine is a high mileage M40B16.

Only thing I noticed after the renewal was that the temperature gauge now rises quicker, and settles at a higher temperature than earlier (thermostat was renewed too)

 

[noctua]

Re: Replacement Water Pump issues

Hi Pings,

Thanks for the insight and welcome to the E30 club (I think there are not many of us out there right now)!

Mine is an M20 and though I do not think the diameter of the hole between the M40 and the M20 is that different, and while fitting was not an issue, the metal covering of the pump did not cover the sides adequately. That being said, the provided gasket was so thin, that it did not cover the entire area fully as well.

The problem was resolved, as mentioned above by customising another gasket around the entire metal covering of the pump, in contact with the engine.

As for the temperature, yes i notice that it settles at a higher temperature. At that time, I didn't know if the issue was the dilution of the coolant (as I had to drain it out again to fix the problem) or it was an effect of the fix. At least, now I know that it might be an effect rather than coolant dilution.

Hi Noctua - another E30 driver here,

Am a new member here - own a 1991 E30 since the last few months. I recently had the timing belt renewed along with the same KWP Water pump - no issues with fitting.

Engine is a high mileage M40B16.

Only thing I noticed after the renewal was that the temperature gauge now rises quicker, and settles at a higher temperature than earlier (thermostat was renewed too)

 

[E36fan]

Hi guys, I just got an 1989 E30 not too long ago, M40B16. Would love to find out more about maintenance etc. if you are still active on this forum!