I have Honda accord '95 - 4 cylinder v-tech engine, 155 K mileage. My car drives fine in freeway at 80 mph temp gauge always steady at 35% (1/3). But when I hit into traffic, (stop and go ) my temp gauge move up slowly to 65% and then only radiator fan comes on. Is this bad for for my engine or this is normal? If open the heater with full blast, my temp gauge comes down to again 35% (1/3). Then it goes back up slowly maybe about 50% if my car continue on traffic stop and go speed.

When my radiator fan came on, I checked the temperature with infra red thermometer pointing at thermostat area (i.e ECT switch A), it was showing about 200 F which about correct, right? If normal, should my temp gauge stay steady at 35% (1/3) controlled by the radiator fan and never allow temp gauge to go up 65% when engine is overheating?

Thanks,and appreciate your comment.

 

Since you have VTEC, is this an EX trim with A/C?

If the coolant temperature is above 199 degrees F at engine coolant temperature switch A, then the switch will close, which should turn on both cooling fans (radiator fan and A/C condenser fan). If normal, your temperature gauge should remain about the same and not show much, if any, change.

 

Both fans should turn on when the coolant is over 199F and the engine is running.

A quick test you can try is to start the car when the engine is cold, and turn on the a/c. This will force both fans on while the a/c compressor runs. If one fan isn't working, try tapping the fan motor with the end of a screwdriver with medium force. Keep clothing and your body away from the drive belts as they could easily injure you.

 

Also be sure there isn't air in the system.......a quick bleed of the system cost almost nothing.

 

Thank you all for your help.
My car is v-tec EX w/ AC (station wagon).
Yesterday, I started my car and turned the AC on, then both the fans came on. This means fans are working.
I also tested ECT switch A and measured its resistance at 200 F in hot water (Thermometer placed inside the water). It showed mostly about 700 ohms, and one time it showed 10 ohms (not consistant). If it is working well, should it be showing zero ohms?

By the way, temperature gauge at 50% (1/2) is approx. what temperature? There is no number scale written on it.

Thanks, and appreciate your help.

 

I admit I'm old, slow and stupid.

95 Accord 4 cyl.

There are four sensors/switches for the temp.......and I'm going to use my terms, sorry.

Thermo A - this is on the t-stat housing where the lower hose connects to the engine. Jump the wires to this green connector and turn the key to on and BOTH fans run. This switch "controls" the fans when the key/engine is on. At about 199 the switch will close...continuity.

Thermo B - this is on the housing where the upper hose connects to the engine. Again a green connector. When the car is "off", at around ~220 (too tired to look up the exact value) it will turn on "ONE" fan. There is a timer that controls how long it will run above the set temp....once below the set temp the fan will stop.

On the end of the head, under the dist. There is a single pin switch - this is the sender for the temp gauge on the cluster.

Also on the end of the head is a two pin switch/sensor. This is the "ECT" switch that tells the ECU/TCM the temp of the engine - resistance.

 

1. Engine Coolant Temperature Switch A is a normally-open type of switch. The test for this switch is to check for continuity when the switch is suppose to be closed. Switch A is suppose to close near or above 199 degrees F.

2. Each Accord may have slight variation showing on the temperature gauge in the dash; however, for most, it will show at about 1/3 up once the car has reached normal operating temperature (192 degrees F - 194 degrees F). 194 degrees F should also be when the thermostat has fully opened.



Overheating Troubleshoot for Honda's Cooling System

Based on the illustration, approximately 50% up would be somewhere above 208 degrees F. Although, not necessarily considered overheating yet, you should check what may be the cause for the rise on the gauge (i.e., is there a cooling problem?, etc.). Usually, most driving conditions will not cause the temp. gauge to rise much, if any, above that 1/3 mark. I had a 95 Accord for about 18 years before I got rid of it, and I never seen my gauge rise to the 1/2 mark.

 

Thanks all again for your comment. Today, I changed radiator fan thermo switch A (after market part). I tested in hot water, it gave continuaty resistance at 200 F (beeped). My old part does not do this. So, I hope my problem is solved.

Redbull-1, thanks on your illustration on temp gauge, says that normal range after 98 C (208 F) up until it reached almost to point red zone. That seems scary because it could damage ones engine if one waits till close to red zone, right?

Thanks again for your help.

 

If you can't bring the temperature back down quick enough when it actually begins to overheats, damage will probably occur. So, not a good idea to let it go all the way to the red zone.