[PJ Smalls]

I have a 65 fastback, that had a 15 gall tank installed and the gauge is not reading correctly, when i fill it up it only shows about 1/2 full, what do i need to do to correct that so it reads correctly. My temperature gauge is also not working. Also from time to time going down the road there's a noise under the hood that sounds like someone is sawing wood, and i've noticed the speedometer flickers in time with the sound, what do I need to do to correct that, would lubricating the speedometer cable work? Please help and thanks in advance.

[5.0 in a 66]

Most repop gas gauge senders dont have the rod bent so empty is empty and full is full. I'd drain the tank and bend the rod so you've got 3 gallons left at dead empty on the gauge, which is SOP for newer cars.

Yes I bet the speedo cable is binding due to lack of lube, and clicking and bouncing as a result. Some ATF or 3in1 oil down the cable should do it.

[fastbck65]

Sound like they still used to old sending unit. Either bend the rod like 5.0 said or get another sending unit for a 15 gal. tank. Speedo cable problem is easily taken care of.

Temperature sending unit contact and wire may need adjustment or replaced. Wiggle it around while someone sets in the car and see if the gauge moves.

[PJ Smalls]

Thanks, I will give it a try.

[red65mustang]

Do you have a plastic float on the sender? Those plastic floats will leak and fill with gas and not let the sender reach full. Both of my Mustangs 65/66 devolved that problem and I replaced with Scott Drake's sender assy with a brass float. There are a couple of things you can check. If you have a multi-meter check the Ohm reading at the sender between the screw post and ground full should read around 10ohms and empty around 60ohms 1/2 tank is about 30ohms. You can check the function of the gauge by jumping the wire that attaches to the sender to ground; the gauge should jump to full. You can check the water temp gauge the same by jumping the wire on the sender to ground and the gauge should jump to hot. If you replace the sender don’t use any sealer on the threads because this will interfere with the grounding for the sensor. As for the cable, the inner wire should come out to be cleaned and checked. If not there are replacements available.