Contour Enthusiasts Group Archives Forums General Troubleshooting Waterpump - plastic vs metal

Well I have heard loud and clear the issue with the V6 water pump and since my SVT has 45K on it I decided to look into replacing it.

Problem:
1)Talked to Ford who said that the waterpumps are still built with plastic impellars since the overall weight(light) is required for the high velocity spin.

2) Talk to a bunch of suppliers who called the water pump factory, and they said they still make them in plastic otherwise the bearing will be shot in 10 thousnad miles if metal

3) Talked to a supplier of metal impellars, and he said, well I have seen no problems.....the problem is these pumps seem to be off shore units and they say they use the metal to save money...Its cheaper than a casting for the plastic.
SO how has the metal impellars hold up?
And why is Ford so admimant on keeping with the plastic??

Many people here have changed to metal impellers with no problems. Those that stayed with the plasitc, nothing but problems. As for why Ford is making excuses to high hell, well, if you made a faulty product, would you tell someone that it was a bad part??? -Nick

I agree with "99". Also, its probably cheaper for Ford to use plastic.
Water pump have been made for 100 years with metal impellers w/o any inherent problems, so the same should be expected here.
Plastic + high RPM + high heat = disaster waiting to happen!

I thought the way go on the waterpump was only metal. However, my local parts store did not have the metal impellor when mine went bad at mile 66,666. So, I popped open the box of the one they had in stock and it was the white plastic. After looking VERY closely at what I thought was plastic, I thumped it, tapped it, scratched it with my fingernail, etc. to see what kind of material this was. It looked and acted like porcelain or something ceramic. It even rang when I thumped it. Call me crazy, but I bought it. It's been running fine ever since. I wondered about having a large metal thing spinning up at higher RPM's, too. I figured if the impellor is lighter, that will take some strain off something.

Anyway, just make sure you don't get the crap black one and you'll be fine.

Your pump went at 66,666 miles? I sure hope you aren't superstitious! That's gotta be a bad sign.

this isnt the main cause for them breaking. the main cause is the metal cone coming loose from the pump housing and rubbing on the impeller until it's worn down enough, or lodges in between it and the housing and cracks it to pieces. the black impeller also suffered a different death as you stated. just make sure you look to see if the cone is loose in the pump housing. if it's in tight then u can buy whatever kind of pump you want. if it's loose then you MUST buy the ford oe pump.

On the contrary, my pump impeller cracked in half almost completely and the cone was just fine. There was no sign of it separating from the housing.
There are somethings that should not be plastic and the pump impeller is one of them. Metal just does not catastrophically disintegrate like plastic does.

I'd like to think that Ford was trying to scavange every last bit of horsepower out of this smallish V6 and perhaps the Ford engineers thought this was a good place to save weight drag, however small the amount it would be. When's the last time you saw a domestic engine that would reach the 7K rpm band bone stock AND put out 80hp per liter? Or anyone's for that matter? Honda and a few exotics and that's about it. And they do it with either fancy valve timing, lots of displacement, lots of cylinders or all of the above. Plus mucho $$$. I'm sure that someone can shoot some holes in my theory but that's my story and I'm sticking with it!

Karl

Edit: By the way, what happens when a metal impeller water pump's cone comes loose? I would imagine it would lose its "pumping power" much the same way as when a plastic impeller breaks. I was thinking that this would eventually happen if all one did was replace the pump and not the whole housing. Moral of the story: Keep one eye on the temp gauge and one on the road.