On my dashboard near my clock the "add coolant" light comes on. Then this annoying long beeeppp comes on. But my temperature is normal and I have coolant in my reserve tank. What should I do? is it that there's bubbles in the system? or is it that I have a leak somewhere? or should I just flush the cooling system...

 

So - you have air in the radiator top tank.

I assume you have refilled it & the air pocket returned.

Most likely the radiator cap is not sealing so coolant can't recover during cool down.

It could also be a small external coolant leak.

Hopefully it's not an internal coolant leak.

 

pull of the rad. cap and fill it , star the motor and look for tiny bubbles int he coolant this means you have a leak somewhere ( heater hoses, colant seal..etc)

 

I've been having the same problem. At first the radiator cap would not hold enouhg pressure and the coolant would leak out above the filler neck. Now the filler neck stays dry and the annoying coolant buzzer comes on like every other day and I can't get any of the reserve to be vacuumed back into the system, Ive replaced the radiator cap at least 4 times, the water pump is only about 2 years old and I don't have any high temp probs with normal city driving even in 100 weather, (I dont' have the underbelly and temp gauge is up about half way on a long hot trip because of the air deflection). If anyone else has suggestions please post them. I was just going to do an entire coolant system overhaul because I'm completely sick of that F****** buzzer!

 

It's has to be getting air in the system from somewhere.

I had a brand new radiator once with a small dent in the filler seal lip.
Even a new cap would not seal.
I also have had a cap whose recovery valve didn't clear the inside of the filler neck.

 

I'm having the same problem but I tried grounding the wire to the radiator (the add coolant wire) and it didn't do anything.

 

It's risky to just shunt that sensor.
You really should fix it.

The warning it gives can save you from being stranded, and can save your engine.

 

It could just be a wiring problem.. My car does it like once a week, but there are no air bubbles, my coolant seals are fine, and my radiator cap is new..

 

Sorry I didn't mean to confuse. I mean that it is acting like the above poster's car. I definitely definitely want to keep the buzzer.

What I meant was I *thought* that grounding the wire, while the buzzer is on, would turn the buzzer off because the coolant in the radiator completes the ground. If it is in fact the opposite, then I have a faulty sensor.

What would be great to have clarified is whether grounding the circuit turns the buzzer on or off. Like I said, I thought grounding would turn it off. Grounding the circuit does nothing to turn the buzzer off.

BTW my Add Coolant light is on otherwise I'd be checking the oil level sensor.

 

You are correct.
The sensor pin sees ground when it's wet.

The most common failure is right where the wire comes out of the plastic plug.
There is no strain relief there so the copper inside can crack.

Pull the plug out of the radiator & clip an ohmmeter on the sense pin & the connector.
Wiggle the wire & see if continuity drops.

 

i was going to say check the sensor and see if its still good. get some clr and clean the copper wire off and then stick it back in and see. if that doesnt work then good luck to ya lol

 

Recovery valve didn't clear the filler neck? Could you elaborate on this, and explain problems this would possibly cause?

 

i am having the same problem, but not as serious as u all, but it still beeps once in a while, but i have coolant and water leakin out of the sensor tho. and when i add coolant again and the beeper stop beepin. i hope i can get a bit advice from u all too.
thx

 

do i have to take off the plastic under body on my 91 NA to get to the bolt to drain the radiator? also where exactly is the bolt to drain it?...

 

My sensor is good. Well I should say, should be good. It is showing some resistance between the wire and a ground. Not horrible though. I removed the sensor and there was no air. Not sur ewhat to check now.

 

No, you can leave it on. Its kinda hard to get to. Remember that the radiator is oblique, so the bottom is farther in than the top. Its near centerline, more to the drivers side, and its a plastic plug that can be removed with a big philips. There is a hole in the underbody that you can look up and forward to see the plug. be careful not to crossthread it when you put it back in. The block plug is on the drivers side of the engine, between the spark plugs, near the bottom of the block.

edit: This is from my 1990 vert. other models may be slightly different.

 

Just wanted to post that I am a moron. While poking around last night looking for a missing vacuum line I found a black connector with a black or brown wire with a white stripe. Realizing that it had foam on it that would have been from around the radiator (sealing the radiator to the radiator support) I looped it up and it just reached the coolant sensor. Doh! I had another wire with a white clip connected to the black clip of the coolant sensor. Quickly tested the continuity and then hooked it up. No more buzzer!!

So don't be a dumbass like me.. hook up the correct wires.