Coolant Leak - Is it the notorious water pump leak?

Hello All!

I noticed this morning after a short ride that the DRZ has a coolant leak. Here's a picture of the problem area:

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It's hard to tell, but almost dead center in the picture you can see the darker coloration from the coolant/water on the crankcase cover. It appears that the water is leak from the area between the water pump housing and the crankcase cover.

Is this the notorious water pump shaft seal leak?

If it is, where exactly does the RTV go on the seal? I've looked at the write up, but am still not sure exactly where the RTV goes.

Any help would be greatly appreciated.

Thanks!

That's is what mine looked like. I did not do the band aid job. When I took it apart the shaft was rusted and pitted, so I just ordered up a new pump assembly and gasket. Put engine ice in and changed the oil and rolled on.

The RTV goes under the white seal on the impeller. You have yo be careful not to damage the seal when getting it out.

Edited by drz400kat

Yes, that is the common leak. The shaft condition as nothing to do with it. When you disassemble the pump you will find a black plastic impeller molded to the shaft. On the back side of the impeller is a white ceramic disc. Blow air between the shaft and the disc and the disc will pop out. The disc is coated with rubber except on the exposed surface. The RTV goes in the cavity in the impeller, then the disc is replaced. The RTV bonds and seals the disc to the impeller. Use only a thin layer of RTV in the cavity. Reassemble so the spring pressure from the mechanical seal in the pump housing presses against the disc to hold it tightly in place. I like Ultra Gray RTV. Usually the only items to replace are the primary cover gasket and coolant.

As for being a band aid fix, it has worked for me for 12 years. I did not invent the fix but I recommend it. Replacing the pump assy is not a bad idea especially on an older motorcycle. The leak could be something else. If replacing the pump, order the less expensive Kawasaki part number. All pumps are the same. Kawasaki pars are Suzuki parts.

Yes, that is the common leak. The shaft condition as nothing to do with it. When you disassemble the pump you will find a black plastic impeller molded to the shaft. On the back side of the impeller is a white ceramic disc. Blow air between the shaft and the disc and the disc will pop out. The disc is coated with rubber except on the exposed surface. The RTV goes in the cavity in the impeller, then the disc is replaced. The RTV bonds and seals the disc to the impeller. Use only a thin layer of RTV in the cavity. Reassemble so the spring pressure from the mechanical seal in the pump housing presses against the disc to hold it tightly in place. I like Ultra Gray RTV. Usually the only items to replace are the primary cover gasket and coolant.

As for being a band aid fix, it has worked for me for 12 years. I did not invent the fix but I recommend it. Replacing the pump assy is not a bad idea especially on an older motorcycle. The leak could be something else. If replacing the pump, order the less expensive Kawasaki part number. All pumps are the same. Kawasaki pars are Suzuki parts.

Thanks Noble!

I will be fixing this soon.

As for being a band aid fix, it has worked for me for 12 years.  I did not invent the fix but I recommend it.  Replacing the pump assy is not a bad idea especially on an older motorcycle.  The leak could be something else.  If replacing the pump, order the less expensive Kawasaki part number.  All pumps are the same.  Kawasaki pars are Suzuki parts.

I have read it works from a lot of people, and that it doesn't work from a lot of people. The kawa part is a lot cheaper I picked mine up for $67 compair to $118 for Suzuki. As for me I couldn't see spending $18 for gasket, $20 for coolant, $30 for oil on a MAYBE + my time is worth more that that. (I know I could reuse oil and coolant) So it was a easy choice for me. Now Im not taking away from the RTV fix if it works for some that's great.

As far as the shaft has nothing to do with it. Now please correct me if Im wrong here, but doesn't the gasket SEAL around the shaft? And if its pitted bad it wouldn't seal up?

Now please don't take this as me being a smartass, I know you are very respected on here for your knowledge. Im really just wanting to know.

You are correct, there is an oil seal (lip seal type seal) that seals on the shaft. However that seal runs in oil and i would not expect it to become rusted or pitted where the lip contacts the shaft. Pits in the shaft away from the seal do not affect the seal. Keep in mind that is an oil seal. Pits in the shaft do not affect the coolant seal. There is no coolant sealing going on, on the shaft. There is nothing wrong with deciding to replace the pump assembly. For many people that is probably the smart choice, especially on an older motorcycle. I just never considered it a "band aid fix". When it works, which it often does, it is very reliable. In my case it has certainly been better than new. Although I did not invent the fix I have often recommended it stood behind it.

Lip seals do wear a groove shaft in high mileage situations. But consider there is a lip seal on the front and rear of the crankshaft, transmission and differential of your car that often lasts well over 200,000 miles. The spring behind the lip compensates for the wear of the seal and the shaft. They are pretty reliable even in harsh environments. But they don't work well as the coolant seal in water pumps. Which is why the carbon/ceramic "mechanical" seal is universal in water pumps for 80 years or so. Now if only KTM would get the message (one of the few that do use a lip seal on a shaft to seal coolant)

Aw ok now that makes sense thanks for the schooling.

As far as the "band aid" fix statement well next time I will try to use better words.

Edited by drz400kat

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