A Potpourri of Problems: Faulty floats, grumpy gauges, and cooling conundrums
Terry Krausz writes: I have a 1969 Plymouth Satellite protected by Hagerty. During restoration, a new gas tank, sending unit, and fuel line were installed. When the tank was filled, the in-dash gauge showed a little over half full, with a slow response time when the ignition was on. Thinking the sender was faulty, I bought a new one. The new sender was connected through the car’s original wiring but not installed in the tank. When tested, the in-dash gauge responded quickly, showing half, three-quarters, and full. I reinstalled the new sending unit and filled the tank again, but I still had the same slow response, with the gauge showing a little over half. Grounding seems good. How do I correct this issue?
Terry, I’m slightly puzzled over the slow response time, but regarding the fill level, if it reads correctly when you manually put it through its paces outside the tank, the sender, gauge, and wiring are fine. I think it’s likely you need to bend the float arm of the sensor down to get it to read full. I’d also recommend checking that the float isn’t filling up with gas, as that will certainly affect the level.
Tim Doyle writes: I own a 1973 BMW Bavaria and have an issue with my gauge cluster: I cannot unplug the round harness connectors from the back of the cluster. They are stuck, and I am afraid of breaking them if I force them too hard. I tried to carefully pry them off with a small screwdriver, but they wouldn’t budge. Any thoughts?
Tim, the round connectors should simply slide off the pins on the back of the cluster. Corrosion may be holding them in place. Try delivering some penetrating oil via a spray straw, then gently pry.
Franklin Henley writes: I recently added a Chevrolet performance serpentine kit to the engine in my ’67 Camaro 327. The kit is for use with reverse-rotation water pumps. As I understand it, the water flow is still the same, just the rotation is different. I also installed a reverse-rotation fan and a Holley Sniper EFI. When I started the car, I noticed that the engine got extremely hot within a matter of minutes—so hot you couldn’t touch the valve covers or any other part. The new radiator was also too hot to touch. I did not replace the 160-degree thermostat, but I did test it, and it was working properly. Any thoughts on what to look for on the overheating issue? I was trying to set the timing when I noticed the heat, so I shut the engine off. I’m not sure what the distributor was set at, and it had not been moved during the installation.
Franklin, I suppose it’s possible that the ignition timing is way too retarded (try setting it to 12–14 degrees of initial advance), but it sounds to me as if the coolant isn’t moving. The question is whether it’s not moving at all or just not flowing through the radiator. If you’re certain that the thermostat is good and the system doesn’t have an air pocket in it, you may need to pull off the water pump and verify that the reverse-rotation impeller on the back spins with the pulley.
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About the symptom of slow response in the gauges; The gauges in the Plymouth B Body are thermal bi metal. The wire needs to be heated for the gauges to respond. The IVR (Instrument Voltage Regulator) which is also thermal operated may not be functioning properly and this could be a warning that it is about to fail (and cause damage). I upgrade the IVR to electronic versions that have short circuit and over voltage protection (rt-eng.com is one vendor I have used).
Another reason why the fuel gauge is slow to read when it’s installed is grounding of the sender to the tank and grounding of the tank to the body of the car. Try running a temporary ground wire right to the instrument cluster’s ground. I think you’ll find the gauge responds quickly.
The radiator in Franklin’s Camaro being hot indicates coolant is indeed circulating so the pump and thermostat are working. 160 degrees is too hot for my hands so I’m not convinced there’s a problem. An IR thermometer is a terrific tool for this; if the system climbs much above the thermostat’s rating (radiator tanks are a good location to check) I’d investigate airflow.
My thoughts exactly. Is he sure he needed the reverse-rotation fan? If it’s now pushing air out the front of the radiator instead of pulling it through, then the cooling won’t be as effective when the car is sitting still, and will be nearly nonexistent when the car is moving.