I know we have a lot of coolant buzzer questions on this board, but I searched and couldn't seem to find anything that would explain my problem.


EDIT: Forgot to include my car! :: smacks self ::
The car is an 88TII.

Starting today, my car's add coolant buzzer will come on when I'm at idle or in lower RPMs. The temperature is normal, and if I rev into higher RPMs the buzzer turns off.

I checked the overflow etc. and they're all full. Curiously, when I checked the overflow with the car idleing and fully warmed up, it was still cold coolant in there. Also, the cap on top of the radiator was pretty cool to the touch, but the cap that looks like it's on the radiator hose on top of the engine was quite hot.

I'm not getting any smoke out the exhaust that I can tell (my buddy couldn't see any driving behind me either), but for a little while earlier today the engine was smoking a bit on the drivers side. It didn't really smell like coolant, but there might just not have been enough of it to smell or something. The temp has not risen above normal once warmed up.

Any ideas?

 

check the sensor wiring?

 

First things first... check the heater hose under the oil filter. I could have a very small crack and only leaks under pressure (this is what mine did)
Second thing... when your car is completely cold pull off your radiator fill cap and sorta massage the tube that runs from the radiator to the fill cap because you might have bubbles (mine also had bubbles)

Good luck

 

Check the water pump drain hole for leaks - should see discolouration below the weep hole if pump is failing - if so, will cause low pressure and trigger the sensor which is a PRESSURE SENSOR and not a LEVEL SENSOR as some dummies keep maintaining on this forum!
Ian

 

Some twits think it's a pressure sensor. Us dummies KNOW its a level sensor. When there is no water touching the sensor........buzzzzzzzzzzzzz.

Simple test. Take the sensor out of its hole. Turn the key to ON. Wait for a few seconds. Buzzzzzzzz. Now, while its buzzing reinsert the sensor in the radiator (I'm assuming its full of WATER not AIR. RESULT: The buzzzzzzz goes away. Dummies 1, Twits 0

 

 

Hailers is right. Not a presure sensor, but a conductivity sensor. No coolant, no conductivity.

The oil level sensor also will trigger the buzzer. Make sure you are not running low on oil and that it is not foaming at higher speeds because of it.

 

I've seen it where you can take off the filler cap, put in a few ounces of water and it will reach the top of the neck. That DOES NOT mean the system is full. By doing the above, and THEN removing the bleed screw on the left side of the radiator, the water level will fall from the top of the neck and NO water will go out th bleed screw opening. That's because you have a AIR POCKET in the top of the radiator itself. You need to pull the bleed screw, then fill at the filler neck til water exits the bleed screw. Then as the water flows out the bleed screw, install the screw and continue filling the neck til it tops off. Install the cap then.

If you have a defective filler cap, the engine will not be able to suck the water back into the radiator after/when the engine cools down. So the cap and the small hose the leads from the filler neck MUST not have a loose connection in the hose and the cap must be servicable.

There's an article at HOW STUFF WORKS.COM that shows how this works.

 

It triggers the same buzzer? Would it trigger the "add coolant" light as well?

Thanks for the replies guys! I'll get out there and start trying some of that stuff ASAP.

 

No, won't trigger the add coolant light, but will trigger the oil level light. Either (and high RPMs) will trigger the same buzzer.

Many people (who have cold solder joints in the clock/warning panel, and don't follow the factory checks) won't have any light come on.

 

BAD BAD BAD!!!!
Well you might have the Symtoms of!!
VOLCANO RADIATOR!!Do you notice your coolant resivor is getting full all the time??

Well it could be to 2 problems.
1- radiator car is worn out so it dosent hold the pressure in your system.(higher pressure means higher boiling point)or
2-combustion leak into the cooling system or vise versa.

It could be at low rpm's only because the water is low then and when you accelerate the motor the water pump pushes water up to touch the sensor.then when back at idle the engine water lever decreases..I had this problem before due to blown waterjacket seal.but i still drove it for about 30k miles just blockwelded it a few times =)..
Did you overheat the car or is it time for a rebuild??
It could be your Connections but If not bad bad bad..
Usually means you got a water\combustion leak..
mabey the waterjacket is cracked or just the seals are out and ur in need of a rebuild soon..mabey the radiator cap.
check this link for a few things you can do about it if it's not the sensor.
http://rotaryresurrection.com/coolantfix.html

Oh yea and Remember to check your water level everytime you start it up and turn it off..I reccomend a pressure reliefe radiator cap so you can bleed off the pressure while your car is hot and take off the cap while its still hot..I do it but be careful you bleed all the pressure first!!..