I have an 85 rx7 gs, and the coolant light has started to stay on. The car is ful of antifreeze and does not appear to have any leaks. I am seeking advice on a possible fix. I was thinking it may be the sensor in the radiator. Can someone tell me in detail how to disconnect the sensor to replace it, or if it might be something else. my email is bparke3@yahoo.com or im at bp3376. any help is appreciated

 

As I remember the first gen sensor is the same as the second gen. It's in the top of the radiator and just screws right out. It grounds out when water (coolant) covers the probe, and when the coolant level goes down far enough it energizes it to send a signal to your trouble light. Screw it out and see if the coolant level is all the way up to the top of the radiator.
hanman

 

should the sensor be in coolant or should it not be covered? I do know where to unscrew it. it is connected by a wire or something, I am wondering how I would change out the sensor, I guess where I would disconnect to replace. Can you specify about the sensor, if it should be in coolant or just above, or how low it would get before the ligth should come on.

 

top

 

Mine comes on every now and then... I say "shut up", if that doesn't work, I say "shut up, Please" (ever see MIB? ) Then it goes out.

I think it's a poor connection in the warning light/beeper ECU. I noticed that my warning beeper stopped working about the same time...

 

The sensor should be covered by the coolant. It sits in it. When the coolant level drops below the sensor it turns the light on, and in my second gen it activates the most obnoxious buzzer I have ever heard in my life. In my first gen, just the light comes on.
If the coolant level is ok, I would guess the sensor is faulty and needs replacement. Again, as I can remember all the RX's use the same sensor, first and second gen.
hanman

 

Oh yeah,
Make sure the overflow tank is full also.
hanman

 

I ordered a new sensor to install, however I am concerned about how to disconnect and install new one. any idea on how exactly it is done? It looks as though the line connected to it goes down to the right front headlight area. I am unsure if there is a simple disconnect plug and I can plug a new one in or if it need to be spliced, etc. any help would be appreciated. The ligth is on however it does not make the buzzing sound like my 87 did.

 

It seems that the first gens SHOULD make a sound when the low coolant light comes on or when you leave the headlights on with the key out.

There is an oscilator somewhere that is flaky... I think it's in front of the battery... Mine doesnt make noise, but others have said it should.

 

it sounds like no one has had their 1st gen make the buzzer noise.. I know mine doesn't.

Should it?

85 GSL_SE

 

it's not a buzzer in mine, it's a BEEP, BEEP, BEEP, BEEP, ad nausium.

--matt

 

When the overflow tank is empty it satrs beeping, mine does it when it gets real cold. Like yesterday -40 C with the windchill.

 

My first 1st gen did not beep nor buzz, it dinged. The coolant level light would come on and it would ding once. If you chose to ignore this and continue on your merry way when the car got to operating temp it would start ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING ding DING. Untill it drove you freakin nuts.

At one point on one car I just stripped the sensor wire and grounded it to a screw on the chassis somewhere.

 

There is a connector in line. Disconnect it and unscrew the sensor. Usually a bubble in the rad will trip the sensor. Park the car uphill with e brake on and chock the tires. Start the car in neutral with the rad cap off and the sensor out. When the thermostat opens, it will burp out the air if you have enough uphill angle. Fill the rad until the fluid comes out the sensor hole and then put the sensor back. You should be devoid of air now. Any ringing or dinging now is from Mike Tyson hitting you in the head before he takes your car.

 

Mine buzzes, and the sensor needs the water to touch it or it will go off. the connector should be a few inches away from the sensor.

 

My buzzer would not shut up either. Many years ago I pulled some sort of box shaped relay up by the drivers headlight and it went off. To this day I have no idea what it was that I removed or how it fixed it, but since my light comes on every day now I am happy I did.

 

I'd like to have it worked... It'd have given me incentive to splice the wire to the sensor.

I'd like to have EVERYTHING work on the car after I'm done putting it together. I'll tell y'all what failed in my oscilator when I dismantle it.

 

If your O rings in the intake are bad you will lose coolant thru the combustion process. This also creates a vaccum leak in the coolant system and the radiator will not draw from the overflow reservoir tank. You must add fluid directly to the radiator if such a problem exists.

 

My '83 dings everyone once and a while when it's cold out. The sensor is located on the top of the radiator. the second gen sensors are shorter then the 1st gen one. I would try getting on from a junk yard thats what i did and now it works fine.