water pump impeller gone bad?

The rads been suggested a couple times so I'm going to get out my inspection mirror and flashlight and see if I can see up there. I had the AC condenser off last year and the rad was very clean at that time. I guess the cat could be on it's last legs, how would I check that?

That's an interesting idea. I did recently replace the belt, who knows, maybe things fit two ways. I'm giving it low odds though because that would make the fan turn the wrong direction and I'd think that would make a funny noise. At least it's easy to check.

Old water pump had started leaking. I took temp reading at several spots but don't recall the readings. I'll have to do it again sometime and see how the top of radiator temp compares to thermo housing temp, etc.

I posted the above 18 months ago and got a lot of helpful answers. Don't drive the vehicle much so just lived with it last summer for the few times I drove it. It was really heating up at the Drive-Through windows and still running hot most of the time on the highway.

Anyway.... a couple weeks ago I bit the bullet and got a new water pump from rockauto. Took the old one off and put the new one on. The old one still looked like new, no wear at all on the impeller. Since they were different brands there were slight difference between the exact shapes of the impellers but nothing that looked significant. The thing I was looking for and the only thing that appeared to be different was that on the new pump the clearance between the impeller and the housing that forms the "pump cavity" was about half what it was on the old pump - along the lines of 0.030 on the old overheating pump and 0.015 on the new pump.

With the new pump in place the truck now runs at the temps it always did before, very cool. Maybe there was some difference in the pumps besides the clearance but I couldn't see any. I've heard from many Pontiac people that they clearance their water pump separator plates on the old V8's because a very slight increase in clearance reduces pump flow significantly so they make it as tight as they can without it rubbing. It's the only thing I can figure for this Ford pump. O'Rielly's gave me my money back for the old lifetime warranty pump, never even asked what was wrong with it.

Interesting but doesn't explain why it ran great for 4000 miles. At least you got it worked out. Will be interesting to see if it comes back in 4k miles.

In the meantime, I actually have seen a WP impeller failure, oddly enough o n a different Ford V6.

Car (late-ish model Mustang) came in with an overheating complaint and a no ise that sounded like a bad WP but customer didn't authorize changing it as there was also a coolant leak from thermostat housing. New housing, stat, and gaskets later, leak gone, car still overheating after a few minutes of running. With belt removed, WP rotated freely and bearings did not wobble . No leak from WP.

thermostat was then removed, reassembled without stat, upper hose removed f rom radiator, water from garden hose would flow through engine/rad in eithe r direction. Engine started and revved, no flow evident through hose. Inf ormed customer that the next step was removing water pump, when impeller sp inning on shaft was found. New WP installed, problem solved.

nate