"Low Coolant" idiot light

02-02-2001, 11:52 AM

Hi all-

Lately the "Low Coolant" light has been popping on right after I start my car in the morning. It usually only happens on cold mornings (30-35 degrees, cold for Northern CA). It never happens in the afternoon, after work when the car is cold but ambient temp has gone up. I checked the puke tank and filled it to the "full" line, and the car doesn't seem to be running hotter.

Yet this problem persists. What do you think? Sending unit or sensor of some type maybe?

------------------
Greg
91 LX Convertible

spinemup · 02-02-2001, 11:54 AM

clean the little electrodes at the end of the sensor in the tank.

302 LX Eric · 02-02-2001, 12:06 PM

Good call, spinemup. Alot of crud will start to build up on the sensors after a while. I cleaned mine off last year - now they look good as new.

If cleaning them doesn't do the trick, it may be time for a new sensor from Ford.

Good luck,
E

------------------
1991 5.0 LX Coupe -37,800 miles

13.17 @ 106.14 mph w/ 2.138 60'

Pro-Charger D-1SC on the way!!!

02-02-2001, 12:16 PM

Thanks a lot guys, but could you tell me what sensor specifically so I can check it out?

------------------
Greg
91 LX Convertible

Jeff Chambers · 02-02-2001, 12:34 PM

The electrodes on my sensor actually corroded all they way off when the car was only two years old (1990 GT). I replaced the entire sensor with a new Ford/OEM sensor and haven't had a problem since.

'clean...We're talking about the sensor that actually extends down into the coolant in the overflow tank. Take the entire cap off the OF tank and there will be a sensor on the end of a 12" extension. There should be two exposed metal tips. The coolant completes the circuit between the tips and keeps the idiot light off. Clean off the tips (if they're still there) to get good, uncorroded contact with the coolant. If the tips are gone, you'll need to replace the entire cap assembly.

------------------
Jeff Chambers
Trophy Stock #3
11.97 Seconds / 114.5 MPH
Chambers Racing Team

02-02-2001, 12:53 PM

Excellent explanation, Jeff. And many thanks to spinemup and Eric as well for your quick diagnosis. I'll try this and let you know if it doesn't solve the problem, but it sounds like it will.

------------------
Greg
91 LX Convertible

[This message has been edited by cleangreenmachine (edited 02-02-2001).]

02-02-2001, 11:52 AM	#1
cleangreenmachine Guest Posts: n/a	"Low Coolant" idiot light Hi all- Lately the "Low Coolant" light has been popping on right after I start my car in the morning. It usually only happens on cold mornings (30-35 degrees, cold for Northern CA). It never happens in the afternoon, after work when the car is cold but ambient temp has gone up. I checked the puke tank and filled it to the "full" line, and the car doesn't seem to be running hotter. Yet this problem persists. What do you think? Sending unit or sensor of some type maybe? ------------------ Greg 91 LX Convertible

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02-02-2001, 11:54 AM	#2
spinemup Registered Member Join Date: May 2000 Location: middleboro,ma, usa Posts: 734	clean the little electrodes at the end of the sensor in the tank.

02-02-2001, 12:06 PM	#3
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	Good call, spinemup. Alot of crud will start to build up on the sensors after a while. I cleaned mine off last year - now they look good as new. If cleaning them doesn't do the trick, it may be time for a new sensor from Ford. Good luck, E ------------------ 1991 5.0 LX Coupe -37,800 miles 13.17 @ 106.14 mph w/ 2.138 60' Pro-Charger D-1SC on the way!!!

02-02-2001, 12:16 PM	#4
cleangreenmachine Guest Posts: n/a	Thanks a lot guys, but could you tell me what sensor specifically so I can check it out? ------------------ Greg 91 LX Convertible

02-02-2001, 12:34 PM	#5
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	The electrodes on my sensor actually corroded all they way off when the car was only two years old (1990 GT). I replaced the entire sensor with a new Ford/OEM sensor and haven't had a problem since. 'clean...We're talking about the sensor that actually extends down into the coolant in the overflow tank. Take the entire cap off the OF tank and there will be a sensor on the end of a 12" extension. There should be two exposed metal tips. The coolant completes the circuit between the tips and keeps the idiot light off. Clean off the tips (if they're still there) to get good, uncorroded contact with the coolant. If the tips are gone, you'll need to replace the entire cap assembly. ------------------ Jeff Chambers Trophy Stock #3 11.97 Seconds / 114.5 MPH Chambers Racing Team

02-02-2001, 12:53 PM	#6
cleangreenmachine Guest Posts: n/a	Excellent explanation, Jeff. And many thanks to spinemup and Eric as well for your quick diagnosis. I'll try this and let you know if it doesn't solve the problem, but it sounds like it will. ------------------ Greg 91 LX Convertible [This message has been edited by cleangreenmachine (edited 02-02-2001).]