Hi.
I'm trying to make sure my 94 civic is roadworthy for college daughter out of town.
A friend changed the water pump and timing belt...I replaced the radiator cap since it was bad and leaking. I now check the radiator and its always full and I see fluid go in and out of overflow.
So.... after driving for a while (with the temp gauge on low side) and then parking, the car engine feels REALLY hot I took a digital meat thermometer and measured the engine right near the temperature gauge sensor and the temp was 206 F. Is that normal or is it overheating ? Near the thermostat, it was around 190F. Is that ok ?

 

on the temp guage, sometimes when I start up, it quickly goes to 1/4 and then just stays there...sometimes when I start up it goes to 3/8 and stays there...
is there anything I could do to determine if the gauge is working right ?

 

It's designed to run at about 190 F, way too hot to touch. After stopping, some "heat soak" may occur.

Check if the gauge wire is secure on the temperature sender which is located underneath the distributor. It is the one toward the back with one wire on it. A high resistance in the circuit makes the gauge read low. Resistance of the sender with the engine at normal temperature should be about 75 ohms.

 

0. dumb question...do I measure the 75 ohms between the sensor and ground ?
1. is my meat thermometer reading of 206 too high (you mentioned 190)
2. if there was an issue with temperature sender would it CAUSE the engine to run hotter or does it just affect the reading on the gauge.

Thanks for your help !

 

Did you bleed the air out of the cooling system after the water pump? Air will cause the gauge to fluctuate. 206 is OK. with a 190 T-Stat. My 90 Civic in the summer is way to hot to touch. My gauge is steady at running temp about 3/8.

 

i have a feeling that the person that did my water pump did not...the guy at O'Reilly's said that Honda's dont need to do that.... so sounds like I should ?

I just did the test on the gauge ..which was to ground the wire, then turn key on and gauge should head toward H and to turn off before it did that.
When I turned on it went to the 1/4 point and stopped... so I was expecting it to move much farther...it should right ?

I would guess this implies a bad gauge ? Can anyone confirm this ?

Next thing I did (which probably wasn't good was to disconnect wire so it was open...when I turned key on, the gauge swung down quickly....I turned off right away.

And my other Q... if there was an issue with temperature sender would it CAUSE the engine to run hotter or does it just affect the reading on the gauge.?

Thanks so much !

 

The gauge did exactly what it should if it is GOOD. That is how you can check them. You need to bleed the cooling system of air. This is critical on Honda.
The way I bleed my 90 Honda Civic is I remove the radiator cap COLD, start the engine & let it run through HONDA SAYS 3 CYCLES I do 4 cycles of the electric fan coming on. It takes up to an hour. Many raise the front end. If you watch you will mostly see air bubbles at the radiator where the cap goes. Use a 50/50 mix of coolant. As the bubbles come out anti freeze may be lost, I just keep topping it off. Add coolant to reservoir if needed.

 

you said The gauge did exactly what it should if it is GOOD"............
wouldn't the gauge have to go towards HOT not to 1/4 ?
When the car reads 212F, the resistance from sensor drops to 32 ohms which I would expect to show as at least half way on gauge
it would seem if I short it, the resistance is 0 and the gauge should show hot

 

FWIW, my '97s temp gauge needle parks itself just shy of the middle anywhere after about 150*. According to my ScanGuage, highway temps are usually around 190, and go up to about 206* when I'm sitting in traffic. Even on the hottest days, I've never seen it higher than 208.

 

so i thought I could just buy a replacement guage from napa or o'reilly's but it turns out they don't see a direct replacement....
O'Reilly's said they sell an aftermarket gauge that would not go in the cluster and a new sender.... he said that if the sendor signal also went to computer it would not be compatible...best I can tell from the schematic that signal does not go to the computer....
Anyone had to replace and what have you done?

Still looking for confirmation that the needle going only 1/4 when grounded means its bad but I think so.
Thanks