Hello,

I hope all is well with everybody. I have a 96 Accord DX, and a few days ago, the coolant temp gauge started to be lower than usual. I checked temps and they were within operating range (195-205 F) according to OBDII. The problem with this is my car has been having overheating issues because the cooling fan doesn't turn on properly, so I don't know if the temp gauge will show if my car is overheating or not. Both fans turn on when the AC is pressed on, and when shutting the car off one fan will continue running to cool down the engine I suppose.

The coolant level is fine, but sometimes the reservoir does go down a bit but there is no sign of leakage. Replaced radiator and t-stat 2000 miles ago. What should the next steps be that I should take?

I would be glad to receive any insight from anybody, thank you!

 

Did you use an OEM Honda thermostat when you replaced the thermostat? Did you notice the lower temperatures just after the replacement, or is this a new/recent symptom?

The temp gauge in your car is controlled by the engine coolant temp sending unit (ECT sending unit). The ECT sending unit only controls the temperature gauge in your car. The issue could be the ECT sending unit, wiring, or the gauge/instrument cluster. You will need to troubleshoot, but not critical for how the engine runs. You won't know if your car is overheating, so you need to address.

The fans not turning on while driving are controlled by ECT switch A. That switch is on or very near the thermostat housing and has a green plastic connector. If you unplug that connector and short the pins on the connector with a piece of wire or a thin paperclip when the engine is running, then both fans should turn on immediately.

 

Thanks for the reply!

1. I used an AutoZone thermostat (supposed to open at 180 F) around 3 months ago but this is a new symptom that popped out a couple of days ago.

2. The Temp gauge does rise and move up, but it is not at the location where it used to be. Would this be any concern? It rises up to the lower blue mark, in comparison to the mid 1/3 mark it used to be at.

3. WIll conduct the test tom, but if both fans do turn on, then what would the next step be? I'm using Prestone green coolant, don't know if that would make a difference in the fan turning on while driving

I appreciate the help!!

 

The coolant type won't matter.

If the fans turn on when you jump that connector, then you'll want to replace ECT Switch A as long as you are sure your coolant temp is over 200 °F. If not, you will have to work upstream electrically.

The Honda OEM thermostat opens fully at 194 °F, so you may want to install an OEM thermostat. They are worth the extra $ and seem to last a very long time. Plus you'll be in that area if you change the ECT switch A and will need to drain the coolant. Use a clean container and you can reuse the coolant.

If you temperature gauge starts to rise, turn on the heat in the car full blast with recirculation turned off. It will be miserable inside the car, but the can help cool the coolant and reduce chances of engine damage. This is just to get you home or to a shop. I don't recommend doing this all the time. Excessive heat can cause a warped cylinder head and a very expensive repair.

 

Will test out tomorrow for the switch. What about the temp gauge, what do you think could be causing a lower-than-usual temp gauge placement even though the operating temperature is 195-205 according to the OBDII.

Thank you!!

 

I'd assume the coolant temp sending unit that controls the gauge in your car is working if the needle moves. I'll look at the shop manual when I return home to see if it has a specific temp/resistance test.