I've been working on my own cars for the better parts of 20+ years but just had a new experiance. I've changed countless water pumps on both SBC & BBC but never had this happen.

Here's the deal.

A friend from our club had his car (20,000 mile 78 PC) in & out of one of the local dealerships for the past 3 months. The car was showing 230-240 on the gauge. The cooling system had been flushed just over a year ago. The dealership went through 2-3 sending units and 2 different gauges. Claimed to put a mechanical gauge on the system and drive it. They said that the car was not overheating.

When he had me look at the car, the first thing that I noticed was that when hot there was no pressure on the upper radiator hose. I am thinking thermostat stuck so I changed it. Didn't fix it. The next thing that I checked was for good flow through the radiator. Nothing was circulating at all.

This lead me to think that the water pump was not working correctly. What was strange was that there was not any normal indications of a bad WP.
No leaks, noises, etc. When attempting to move the fan it was a little loose but not really that bad.

Putting on a new WP got everything flowing again & the temp on the gauge is back down around 180-190.

I pulled the back off of the old one expecting to see a bad impeller or something. But there was not any visual indications of anything being wrong. Everything was solid and clean. No blockages, rust, damage, etc. Nothing out of the ordinary.

Every other time that I have seen a bad WP there was some sort of indication of problems. Leaks, noise, fan wobbling bad, etc.

Is this one of those "one in a million" type occurances???

Anyone else had anything similar?

I have the problem fixed so it's not a big deal. Just thought that I would share this and get some other input.


:cheers: :cheers: :cheers:

 

some times we fix things and don't know the how's or why's (good job) some-
one needs to let that dealer know their tech's need more training before their
rep. get's hurt.... no good thought's right now on no flow if impeller is turning
on shaft , if it's in correct position on shaft, and this pump wasn't put on,after,
mayby a overheat,or leak in seal, (?wrong rebuilt pump)

 

Like comp said...maybe wrong pump for the car? A trick from the old days was to install a pump with a smaller impeller than normal to save on horsepower. Maybe pump was okay, but just not powerful enough to get the job done.

Dep

 

Thanks, good thoughts. :cheers: :cheers:

This was the original, factory pump on the car. The car is completly original with only 20,000 miles.

I hate the situations where you fix something but then can't find the how or why it wasn't correct in the first place. :auto: :crazy: :crazy:


[Modified by DaBo, 11:23 AM 11/30/2003]

 

DaBo: How was the impeller attached to the shaft?

Dep

 

Like DEP said impeller attached, or was the shaft snapped?

 

this one buggin' me... didn't the heater work ok with old pump?

 

Heater worked fine....impeller and shaft were solid. There was a slight bit of movement when the pump was still mounted and I tried to wiggle the fan, but nothing really that bad. The internals were almost as clean as a new one.

You think it's confusing you???:crazy: :lol: I usually don't worry too much about this stuff, but it's just really odd. :yesnod:

Thanks for your comments and ideas.

 

Was the impeller bolted on or was it removeable?
Only other time I had a problem like this it was with a fan clutch that had gone bad. Did you check the fan clutch for proper operation? They can sometimes be "iffy"...work sometimes and then sometimes not.

Dep

 

does it work better now? the system is simple so most time's problem's are
to.. trust me this problem with sneak up on me just after i forget the cure,
then it will give me a head ach. i've started odd file's for reference, gotta'
figure out filling system for them, what a circle

 

In all the decades of messing with cars, I have noticed two differant types of impellers, the cast iron thing that seems to have no particular pattern to the ridges in the impeller, and the stamped steel plate thing, they seem to have a particular twist to the impeller blades and for a serpentine drive pump, it would have to be twisted the other way, or VERY poor circulation would result.....
someone either mixed the pump style, OR the factor goofed and used the reverse blade from what the car needed......notice it's the pump turning direction...not reverse cooling or some such....

GENE

 

Impeller (stamped) is pressed onto the shaft. Fan clutch seems to be OK. When engine is off you can spin the fan and it will not turn a full turn. Fan clutch should have no effect on the water pump turning and moving water. One of my first thoughts was that the shaft was broken internally. This would have the water pump pulley turning but the impeller not moving on the inside. This was not the case. When grabbing both ends of the shaft, (WP flange and impeller) there was very little axial or radial movement .

That's the reason I bring this up. This will happen to me or someone else a few years down the road and we will be wondering whats going on.


[Modified by DaBo, 12:35 PM 11/30/2003]

 

I think GENE mail have nailed it with backwards impeller. ONLY other possible thing would be some kind of blockage in the hoses or passageways.

Dep

 

I will compare it to another pump.

 

please do, thanks let us know!!!! one of the great things about this forum stuff, with enough imput we all get wiser...

 

No help......Looked exactly the same as 2-3 others I had laying around.

:confused: :confused:

 

DaDo, I'm like you. I got to know why :confused: I would like to see this pump installed on another car and see what happens????

 

I'm still wondering about blockage somewhere. If the pump is 100% functional, I don't see any other explaination.

Dep

 

Well the only other option that I can see is you had the belt on backwards :D :leaving: :lolg:

GENE

 

That's NOT even funny.


:lol: