PearsonFan

Does any one know if the fuel level sending unit from a 1973 98 will work in a 1971 98 . I cant seem to find one for a 71 but the NAPA store I work at can get one for a 73. My cousin tells me that his 71 has 2 pipes (fuel and vapor) facing toward the front of the car and in the pics of the two available for the 73, one of them has the same configuration. He has not removed the tank from his car yet, so he is going by what he can see from underneath and his 71 Olds Service Manual. Any help will be greatly appreciated.
Thanks.

Earl Nagle

jaunty75

I just put a fuel gauge sending unit made to fit a '73 Buick LeSabre into my '67 Delta 88 because I could not find a new sending unit correct for my car. It works like a champ. I would think that the '73 Olds unit would fit in the tank of a '71 just fine.

As far as the vent lines, the original unit in my car had only one outlet pipe, and that was for the fuel itself. The tank is vented by two openings on the front right corner that are connected to hoses, each about two feet long, that terminate up under the car. This was before anyone cared about fuel vapors escaping to the atmosphere.

The sending unit for the Buick DID have a second line coming out of it that apparently connects to a return line from the fuel pump or something like that when actually installed in a '73 Buick. All I did was cap this line when I put it in my car as it's not needed.

PearsonFan

Thanks for the input. I'm going to order the 73 unit and we will see how it goes. My experierence with jobs simlar to this in the past suggested it might work. I'll post how it works when we get it installed.

jaunty75

The gauges from that era (and maybe today, too?) all work the same way. They're variable resistors that go from zero to 90 ohms, with zero ohms meaning empty and 90 meaning full. The dashboard gauge is basically just a resistance meter where the ohm readings have been replaced with "E," "1/2", "F," etc.

The only real issue is whether or not the tank is deep enough that the unit will fit without the intake pipe and the filter attached to it contacting the bottom of the tank. On my car, the original intake pipe was about 1/2 inch off the bottom of the tank, and the new one fit in without a problem. I held the old and new sending units up side-by-side, and they looked identical in height.

This also shows you that you can never run your gas tank completely dry as the drain is not in the bottom of the tank like a bathtub. I'm sure this is to prevent sludge and debris that accumulates over the years from clogging the filter as getting inside the tank to replace it and clean things is not something that's part of routine maintenance.

When the level of fuel in the tank falls below the bottom of the intake pipe, there is still about 1/2-inch worth of gasoline on the bottom of the tank. Given the cross-sectional area of the tank on my car, that means that there would still about 1.5 to 2 gallons of gas left if I were to ever run out of gas. Keep that in mind if you're the type who likes to let their fuel gauge get down to the "E" mark regularly before filling up. Those 2 gallons are 2 gallons you can never get at. Your usable fuel capacity is about two gallons less than the listed fuel tank capacity.