Water pump Gates or GRAF

Had a better look during weekend and the "substance" in the expansion tank looks and feels like rust particles not oil. It does not feel slick. I'll be replacing the pump with the aluminum Graf unit soon, hoping I'll last more than 100k at least.

I ordered the Graf aluminum water pump kit from ECS Tuning and did the job this past weekend. I'm glad I took the intake manifold off. I did some carbon cleaning while I was in there, I was surprised to see how much build up was in there for a 70K engine. I don't really see how I could have replaced the pump without removing the intake manifold

I went to the dealer and after a long discussion about plastic vs metal impellers (they thought the VW branded pump was metal) a nice gentleman at the dealer ordered me a Graf branded aftermarket pump for $100 Canadian all-in.

I bought this KIT from SHOPDAP and it was a breeze to install. The price at SHOPDAP is great too.

Graf with the metal impeller. No issues.

I purchase the all aluminum pump made by Graf from FCP euro, they have a lifetime warranty, free shipping and good prices. I removed the manifold to get to the water pump. I had a problem with the cheap thermostat that came with it. It caused my car to run hot.

My '89 325iX doesn't put out much heat at idle, but as soon as I rev it to 2000 rpm, the heat starts coming out of the vents. At idle it is around 65°F air and at 2000 rpm it goes up to around 95°F (it is ~35°F outside today). I noticed a whistling noise that seems to come from the water pump at idle. Once the car got to normal operating temperature, I noticed that at idle coolant stopped coming out of the bleed hole. If I revved the engine a bit, coolant would flow. I replaced the water pump (Graf) 2900 miles and 3.5 months ago. My intuition is that the water pump isn't generating sufficient pressure at idle to move the coolant through the heater core.

16,000 Miles (12 months) and now the Graf is leaking. After researching it seems a few bearing failures, a few thermostats, and some sensors out of the box are failing on these Graf pumps.

I just bought one of these Graf aluminum pumps for an engine that I am building, but before installing it I asked around with the VW tech friends I know what their impression of it is. The consensus was "not great". One shop had to warranty two of them because the seal to the block failed, tearing at a T where it connects the two passages.

I have seen early failure with the Gates water pump and wont use them.