Hey guys I have a 96 honda accord lx. I recently did a coolant svc every since then my heat guage flu fluacutaes to hot and back to normal after drivin for a long time I check the coolant system to see if any air in system and bleed it and today started doin again check coolant is full lower hose is hot. Could it be a bad coolant temp sensor or small leak???

 

Do the cooling fans come on and cycle, when the car sits and idles? [temp about 1/2] Does the temp rise sitting at stops and drop when moving?

As far as a small leak, are you adding coolant? Hot coolant leaks have a funny 'sweet' smell.
The temp gauge sender unit is the single pin plug in the head under the distributor;
Alldata calls out approx. 150 ohms cold engine [70 degree] and 30-40 ohms at full engine temp [fans cycle]
The other thing to consider is that if the wire is grounding somewhere [low ohms] it will cause a rise of the gauge.

 

I would start with inspecting of what you can see. What condition is the radiator in? Feel the core down toward the bottom below the fans. Is it gluey? Let it idle and check the fans. If they do not come on you need to determine why. The coolant must circulate for them to come on. I have seen struck thermostats prevent the fan from coming on. Air in the system can give you similar problems. When you did the coolant service did you run the car until the fans came on? That is the way I decide that the thermostat opened and the engine is now full of coolant.

 

thanks guys for replyin and to answer ur guys question yes the fans cycle and yes it goes up at idle and goes down when drviing and yes i let the car run till fans came on when i did the service

 

ooo and also no im not losin coolant i think maybe coolant temp sensor is bad and thermostat lower hose is hot

 

Check the fan switch. one of my fans was randomly shutting off, and that was causing the car to "overheat".. that fixed it

 

yep i changed the fan control swtch by the themrostat seems to be good now thanks anyways