Aux water pump leaking! Arrrrgh!

[ConvGeorge]

So I went to the grocery store last night, then stopped by the gas station. When I got out, my car flashed a low coolant warning. I've had the car parked on the grass for the past week because my driveway is full, so I didn't notice any water spots. I've replaced my entire cooling system within the past couple of years - except the heater valve. I was having a problem with the AC blowing hot air, and it was suggested I check the heater valves to make sure they weren't leaking (internally, not externally,) and indeed they were. So I have a repair kit sitting here, and I was actually thinking about doing the repair in the next week or so, since I seem to be catching up on some projects.

I went outside this morning to see how low it was - it was more than a gallon low! I filled it up, and didn't see any immediate leaks, which I found kinda strange since it leaked out a gallon in less than a 3 mile round trip. Then I started it up to bleed it, and water started pouring out the back side of the engine. I shined around with a flashlight, but of course couldn't see anything. I then had to rearrange the cars and boats in my driveway because I was thinking the leak was from one of the water pipe o-rings or maybe the valley cover gasket (even though both were changed when I put in my engine last year.) So I pulled the intake off so I could get a better look under there, and surprisingly it was dry at the back of the engine. I started feeling the heater hose and they were dry too. I squeezed the radiator hose and could hear water spraying out back there. Finally I pulled the heater valve out, and water was leaking out a small bleed hole in the bottom. What a pain in the rear.

I guess it's a good thing I never got around to the heater valve repair, because it looks like I'm getting a different one (not new, heck no I ain't paying $500 for one)!

[Timm]

Unless you use restorative heating (running the heater when the engine isn't running) just bypass the aux waterpump - you won't miss it!

[ConvGeorge]

Yes, that's what I was thinking, especially since I can get a new e39 valve for $50 (see below for even lower price!)

So I took apart the pump and valve assembly and here's what I found. So the water pump is pretty interesting. Its vanes are driven magnetically through a plastic cup that separates the electrical and mechanical parts. The cup has a spindle the vanes ride on. The bottom of my plastic cup completely detached from the sides of the cup, and that's what allowed the water in. If the cup was available separately, it could be fixed easily. The valve portion is also in pretty sorry condition. All the rubber is worn, so even if the valves were working I don't know if they would seal. Furthermore one of the solenoids is full of water, so it's probably not working too well anyway.

UPDATE: I just checked, and the valve kit I got off eBay wouldn't work anyway, the valves are a totally different size in the stem, and not long enough. It's probably the one for the heater valve I just ordered (no aux pump, it was $26.)