Q: Check engine light was on and now temperature gauge go hot ? i replace the thermostat but still go hot .help ?

It sounds like you may have a number of issues going on. Overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, a clogged radiator or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. You may also have a water pump that is beginning to fail. Water pumps often times will begin to produce a bit of a whining sound when they are starting to fail. A common problem also associated with this is the water pump may begin to leak around the water pump shaft due to the seal being damaged. In addition to leaking around the pump, you may have a leak elsewhere in the cooling system coming from one of the hoses going to or from the radiator. Lastly, you may have a failing cylinder head gasket allowing coolant to leak from the water passages into the cylinders resulting in the coolant being burnt in the combustion chamber with the fuel. If this is the case, you may also notice a bit of white smoke coming from your exhaust which is a product of the coolant being turned into a steam like vapor.

The speedometer not working could be a result of a couple of things. The [instrument voltage regulator]((https://www.yourmechanic.com/services/instrument-voltage-regulator-replacement) regulates the voltage supplied to the various gauges in your vehicle’s dash. When this is not working properly, this may cause the gauges in your dash to dim or flicker erratically or in some cases provide false readings. This may also be caused by a faulty instrument gauge cluster.

This may also be caused by a faulty transmission speed sensor. The speed sensor reads the rotational speed of the reluctor wheel, located within the transmission. The speed sensor also controls the anti-lock braking system. Driving with a bad speed sensor usually causes the ABS to malfunction and can lead to loss of braking power and/or an accident. When this is not working properly, you may also notice the transmission hesitating to shift gears, erratic tachometer readings, the speedometer not working properly or the odometer not working properly. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle to properly diagnose and repair.