Hi everyone,

I have a 1990 Civic wagon and have replaced the temp switch (on back of the block), temp gauge sending unit, and temp sensor. I had an issue with the cooling fans not coming on and discovered I had a bad engine temp switch. After changing all the parts, I took a photo of when the fans turn on in relation to the temp that the gauge indicates.

Does this look like a normal gauge temp for the fans to come on? To me, it seems a bit high but the fans bring the temp to just below the thermometer symbol on the gauge which seems like a normal operating temp.

I was idling at a traffic light recently and the temp started creeping up to about what the gauge indicates in the photo and then the fans turned on. I have driven the car several times since replacing those parts and the gauge really hasn’t read that high since before I replaced said parts. I just want confirmation that the fans are coming on at the proper temperature and not overheating the car. I have no coolant loss and no coolant in the oil. I have purchased a new radiator cap since that is about the only thing I haven’t replaced. I do have an infrared thermometer which is my next step but I wanted to ask here first.

 

Not normal, Did you buy the sensor/switches from the dealer?
Ive had issues with coolant sensors and stuff from autozone etc. They are not calibrated correctly. Got "new" ones at the junkyard free
Bleed yuor coolant.
Fan switch should trigger at about 180 oem thermostat is at 172

 

Thanks for confirming my suspicions. I believe the "OEM" Facet temp switch I bought is rated for 90-95 degrees Celsius, compared to the original switch, which is 88.5-91.5 degrees Celsius. I had a similar issue with a temp switch I replaced in my other Honda, which was not correct despite the manufacturer's claim.

To answer your question, I purchased this switch on eBay after finding out that the Honda part is discontinued. I try my best to use Honda parts, but it isn't always possible. The hunt begins for a properly rated temp switch. I'm considering going to the junkyard, but who knows how long the switch will last, especially coming from a 100k+ mile vehicle. The original temp switch on my car died after 138k miles.

 

The temp switch on my car has lasted 60k miles so far and it was free. just grab a couple

 

Here’s the update:

I was able to find a NOS Honda temperature switch for less than an OEM replacement. And in the original box which is fun.

I also replaced my radiator cap as well with a Honda branded cap just because. Looking at the switch that I replaced the original one with, it was calibrated to activate between 90-95 degrees Celsius. The factory service manual indicates that the switch should come on around 88-92 degrees Celsius.

Sure enough, after replacing it with the Honda switch, my fans come on when the needle indicates half way on the gauge. What a relief!

My note to everyone is to be careful with parts that are said to be “OEM” replacements. It’s always best to find NOS or genuine Honda parts when possible even if they are a bit more expensive or take longer to find. Beck Arnley is said to be the most reliable brand for OEM parts since they actually were a supplier for Honda back in the day.