96GS#007

From time to time I see threads where people are installing electric water pumps and ask about warning lights. I finally got around to digging into my photo archives and uploading a few shots of what I did when I had an electric pump on my GS.

Schematic (courtesy the F-body crowd)....


LED placement in the center vent. When driving, the LEDs are barely noticeable unless they are lit. I had to brighten this shot so they would show up. If you look close you can also see my shift light...


Bad pump or no power to the pump would illuminate the red LED...


A bad ground would illuminate the yellow LED...


The wiring and components are very straight forward. The challenge is routing the wires. The center vent, the bezel, the trim around the IP display, and the knee bolster on the driver's side all need to be removed so that you can neatly route the wires. Nonetheless, I think having a warning system is valuable since if an electric pump dies and you don't see the analog temp gauge spike....Boom!

The reason you have to watch the analog gauge is because with no water flow, the coolant in the water pump housing (where the sensor for the digital display is located) stays cool....right around 190*...ie perfectly normal...'cept the coolant in the block and heads (where the analog sender is located) is overheating.

mcm95403

Very cool and helpful post. The Mods should sticky this one!

Chuck Tribolet

If the pump stalls, but will still conduct electricity, the LEDs won't light.
Maybe with a properly sized fuse, the fuse will blow and light the LED.
A stalled pump will pull more current than a running pump. You may
need a slow-blow fuse to handle the start-up current of the pump.
Size the fuse to handle the steady state running of the pump by just
a little bit. Some experimentation will be required. Carry a bag of
spare fuses.

I'd put the fuse before the relay, and as close to the battery as
reasonable.

What's the logic behind an electric water pump? Mechanical pumps
are pretty bullet-proof except for the seals, and an electric has the
same exposure to seal failure.


Chuck

96GS#007

From a theoretical perspective, I suppose the pump could stall and still draw electricity. Realistically, I can't imagine how slim those odds would be. Certainly something for everyone to be aware of.

I haven't run an electric pump for years, but I did exactly as you mentioned, the fuse was just slightly bigger than typical current draw.

The reason for the pump....If it fails, it doesn't leak on the Opti. There is no external weep hole. At idle, the electric pump will keep the car cooler longer....it flows more. Drag racers like it because they can sit in the pits after a run, turn the engine off and turn the pump plus cooling fans on and cool things down very quickly. It also frees up ~7hp at the wheels. The added drag on the alternator is far less than the drag imparted by the mechanical pump.

Why did I get rid of it? I use my car for track days. At 6000 rpm, the electric pump flows roughly half of the mechanical pump. When I made the jump to my 383 and 500+hp at the crank, I was concerned about the ability of the pump to keep things cool during extended high rpm operation.

STEVEN13

Good information!

I always like your Threads!

Regards,
Steve

Chuck Tribolet

Thanks for the "why".

Most DC electric motors will still flow current when stalled, for example
by some debris in the coolant.

What sort of pump do they use? One like a mechanical pump? Or
an impeller type? Or ???

Chuck

96GS#007

There's no way debris in the coolant is going to stop or impede the Meziere or the stock pump for that matter. If it would happen, the engine has bigger issues...namely it's getting ready to grenade for some other reason.

At any rate, I've offered up a solution that gives some amount of warning. It served me well for the 5 or so years I ran an electric pump. If people don't like it, they can run blind or they can design their own setup. I have no skin in the game.

93 ragtop

Another advantage to the electric, it allows you to run a standard double roller timing chain, which is much stronger then any of the LT1-4 designs not to mention cheaper.

You eliminate the seal where the shaft passes from the motor to the pump with a freeze plug. (LT series are driven by shaft from the timing chain gear and not belt driven) The orig. pump housing is still used. You just remove the front plate and bolt the sealed pump in place of the pump. By doing this you have eliminated the weep hole as well. So a leak from the pump is virtually impossible with the electric version.

MarkBychowski

Thanks for the post! Now I just have to get my butt to Radioshack...