99 Mercury Sable LS low coolant light?

Question

My 99 Mercury Sable LS has a few problems just wondering if anyone has any advice or input.
First of all, the low coolant light is staying on. But the coolant resevoir is full. after driving the car about 25 miles today i stop to get gas. i filled up and upon starting the car up with the a/c on and taking off down the road- the heat gauge went up all the way to "H".
I heard that turning on the heater would pull hot air away from the engine- and causes cars to not overheat- so i did that and it went back to normal mid range b/w "C" and "H".
The car wasnt smoking, or the coolant boiling or anything funny. it ran fine also.
Im taking it to the mechanic in a couple of days- but before I wanted any advice of what to expect and prices.
If its just something that needs to be flushed or anything minor would it still cause the gauge to read hot even if the car may possibly not be overheating or does the gauge always accurately read that the car is hot and is overheated

Answer 1

The 99' Mercury Sable comes with several sensors which can malfunction. There is a sensor which determines if the coolant level is low. It might need to be removed and cleaned or replaced. You also have a thermostat which controls the gages the driver sees on the dash. If you are positive the vehicle was not overheating when this Gage read hot then it is more then likely this thermostat that is malfunctioning. Most coolant system parts are not that expensive. It will be the labor that will cost you the most.


After rereading this it sounds like you may be low on coolant anyway. It is possible that something is stopping coolant from returning to the radiator from the overflow reservoir as the engine cools down. What you should do is let the engine cool off (a couple of hours without running will do this). Then you should open the radiator cap and visibly check the fluid level. If you are low the shop should check your cooling system for leaks.

NOW, Mr. Knowitall, <<<---(That's what you think).... The thermostat/sensor I am talking about does actually measure temperature of the engine and sends a signal to the driver. (This thermostat/sensor, depending upon the model, is either screwed into the head or block and has wires running into the wiring harness).

Yes, there is a thermostat within the coolant path which regulates the flow of fluid therefore regulating engine temp. Which if malfunctions could actually cause an overheat situation. (They said the car was NOT overheating). All of the things Mr. Knowitall mentioned in his last sentence could not cause a vehicle to overheat and then cool down. The overheat situation would most likely persist if these were the problem.

Let me get specific:
1) I own this vehicle and had this exact same problem.
2) I had a hole in a radiator hose.
3) This caused a slow loss of fluid.
4) Due to this hole the system as it cooled would suck air instead of fluid from the overflow resovior.
5) The system due to having a low fluid level would heat up and cool off fast when the heater was turned on.

Answer 2

OK, now for my two Cents.

The thermostat does not control the gages as someone else suggested. It controls the temperature of the water in the cooling system.

I don't recommend flushing the coolant system yourself. Primarily because it's a pain in the butt, and, what will you do with the old coolant and flush stuff?

It is possible that your thermostat is not opening all the way.
It is also possible that your radiator is becoming plugged.

There are other things like, belts, water pump, head gasket, cooling fan not working., etc.

Answer 3

99 Mercury Sable

Answer 4

Perhaps the coolant bottle has a leak and needs to be replaced.

The low coolant light attaches to the coolant bottle. Having worked at a Ford dealership, a new bottle costs about $60-70 plus installation.

Replace the coolant bottle and the problem should go away. A friend of mine has a 97 Taurus and she needed a new coolant bottle when the heater stopped working.

Answer 5

i have the same problem with my car.i have a 97 mercury tracer.the only thing i can figure out is radiator needs to be flushed.you can buy radiator flush at an auto parts store.just tell them what you need .

Answer 6

sounds like the thermostat and those are real easy to replace on ur own ya know

Answer 7

It sounds like you need a new thermostat.