If it takes 30.00 to top off the gas tank, but the gas gauge shows full on an 85 F150 4.9 Straight 6, it is likely that the gauge is not reading correctly. Replacing the gauge cable can remedy this.
My 2001 had the same problem. There is a GM recall to replace the sending unit.
You probably could A) replace the gauge or B) take it to a dealership and have them look at it
If you problem is that the gauge shows oil pressure with the engine off, you have a gauge or sending unit failure.
The gauge reading has nothing to do with the overheating problem. Misleading and irritating yes, but not involved in causing it.See "Related Questions" below for discussion on replacing the temperature sending unit, and also a comprehensive diagnostic guide for overheating problems.
Your check gauge light comes on if : your coolant temperature guage shows the temperature is high your oil pressure gauge shows the oil pressure is low or your fuel gauge shows the fuel tank is near empty
If it shows hot on the gauge and it is not hot, there is a gauge or sensor problem.
The gauge does not cause the heat; it only shows what it is.
check your answer
A fuel gauge.
Failed gauge, wiring, or level sensor.
Check your temperature gauge. If it shows the engine is running in the normal range then there could be a problem with the "air door" that controls how much air is brought in through the heater core. Or the core itself is plugged and needs to be flushed out. If the guage shows the engine is running cold , then you should have the thermostat replaced.
The symbol used on the Renault Scenic for a problem with the radiator is a thermometer. There should also be a temperature gauge on the dash that shows the current temperature of the radiator fluid.