Last week my low coolant buzzer started going off in my '90 N/A vert. (approx. 208,000 miles). I pop the hood to find that my coolant tank is full, with nice bright green coolant. Kill the car, restart it, and after 10-20 seconds, buzzer goes off again. I repeat this two or three times, and finally the buzzer stays off.

Driving the car, I have no overheating issues at all. Temp stays dead center on the gauge once the car is warmed up. I started thinking that maybe my accessory belt was stretched out and not spinning the water pump fast enough, as occasional reving of the engine also SOMETIMES stops the buzzing. However, it will do this randomly, regardless of what the RPMs might be at any given time. Sometimes it's harder to get it to stop, and sometimes it will not stop at all. Other times it will start buzzing after I'm on the road. This morning, it ran fine and never triggered the low coolant warning at all. But leaving work....BZZZZZZZZZZZ.

Then on Saturday, I had something else start happening that had never happened before. Occasionally during brisk accelleration, and all the time during spirited hard left turns, water will come pouring out from under the dash into the passenger footwell. Now, I'm not talking about a few drops. I mean that after two or three left turns the carpet is SOAKED. I smelled and tasted it, and it's not coolant (though once today I caught a whiff of coolant when it happened). It's pure water. My original thought had been that it was condensation from the A/C system or the weekend rain storm had left me with some water pooled up somewhere. But it's been several days now since rain, and every time I drive, there's more and more water. And I had the top down all day today, so I didn't use the A/C at all. It started as a trickle on Friday, and has progressed until today it's like I'm dumping a glass of water on the floor.

Saturday morning at Cars & Coffee, I met HOZZMAN from on here. After mentioning the low coolant buzzer, he said it was probably a faulty sensor. But then the water issue started, so I'm hesitant to immediately blame the sensor. It's probably wisest to go ahead and change it since they're cheap, and then go from there if I still get the buzzing. But still......

Does anyone have any ideas regarding either (or both) of these issues?? The buzzing is about to drive me bat-**** crazy. And the water is starting to seriously irritating my OCD tendencies.

 

From what you described in the first 2 sentences, you have air in your system. Have you changed your coolant recently or something? Right after i got a coolant change my low coolant light and buzzer would go off. Scared the **** out of me too, i was on the highway and all i heard was BZZZZZZZZZZZZZZZZZZZZ.

About coolant coming out from under the dash...... I have no clue.

 

Have you actually checked to see if the level in the "Radiator" is full?

 

yours s4 or s5?

check the filler neck on the other end of the upper rad hose that goes to the top of the motor.. if yours is a s5 its plastic and might be like mine and cracked.. change that and it wouldn't hurt to get a new radiator cap as well if you haven't already changed it.. sometimes its the simplist crap that causes problems..

as for the water on the passenger side footwell.. i have no clue how thats happening?? sounds odd to me...

 

I would approach this as two separate problems that might be related but might not.

Your overflow tank issue could just be the result of a bad radiator cap or a faulty tube between the tank and the fill port...replace both and see what happens.

The underdash leakage can only be one of two things...excessive condensation from the AC or a leaking heatercore (either the fittings or the core itself).
There is a drain tube on the AC section of the underdash climate control, maybe it's clogged and not draining properly.

Both of these are relatively simple/inexpensive to try and might solve your problem(s).
If not, probably the next move would be a pressure test of the cooling system.

 

Thanks for all the helpful replies!

Nope. Haven't touched the cooling system, other than to check the fluid level in the overflow tank. It's not coolant coming out from the dash, it's pure water.
Not yet. I've only had the car for a few months. So I never noticed until a few minutes ago that I actually DO have a radiator cap. I had assumed the RX was like my Contours, with only the overflow tank fill to add coolant. I'll check this once she cools down.
It's an S5. I'll definitely check that out.
Thanks for the tip on the A/C drain tube. Is it buried under the dash, or is it easy to get to?

 

OK...ran outside to check a couple of things. The plastic elbow connecting the upper radiator hose to the engine does NOT appear to be cracked. Opened the radiator, and there wasn't coolant right up to the top. Since my overflow tank was full to the the rim, I siphoned some out and poured it in to the radiator. It probably took something around 20 oz. or so to fill the radiator up. I'm guessing there's a little air trapped somewhere in the system since the overflow tank was so full. If after I drive it this afternoon the overflow tank is full again, then I've probably got air trapped somewhere. But so far I've seen nothing to lead me to suspect I have an air leak into the coolant system. The lid appears good, but was definitely easier to remove (spring-loaded-wise) than any radiator cap I've ever taken off.

 

Have you checked to make sure the line that goes from the coolant bottle to the rad isn't leaking? It's easy for the system to dump coolant into the tank, but if the hose is damaged or leaking it will struggle to siphon it back into the rad.

 

I'll definitely check that too when I can get under it. I'm currently living out of a hotel for 7 weeks while I'm in training for work. So wrenching is a little difficult at the moment.