Low Coolant Sensor

[SolarSteve]

I am away from my Bently at the moment and though I'd ask you guys a quick question about my low coolant sensor.

I got in my Jetta this afternoon and started it and the coolant light started flashing.  With the engine running I checked the coolant level.  It was full, but I topped it off a little more, the light kept flashing.  I unplugged the sensor connection and plugged it back in, the light kept flashing.  I check the water pump belt (on and spinning) and felt the top radiator hose (firm) and decided I need to go, so I drove it. 

I kept a close eye on my temp gage and it acted totally normal.  Once it got to normal operating temp, I stopped and with the engine running I checked the top hose again, it was hot and firm.  So I pressed on.  I drove about 40 miles and the temp gage remained normal.

I took a look in the owners manual and the horn is on the same fuse as the fan (which is hard wired to a switch from 2 owners ago) and the horn works, so I am assuming the fuse is good (didn't have time to check it).  The coolant ball is pretty old and not very see through and I wanted a new one anyway, so I just ordered one from GAP with a low coolant sensor installed.

So, is it common for a sensor to just fail?  Yesterday, no light, this afternoon, its flashing...  the ball was only $18, so I figured thats not too bad.  I don't like to to just through parts at something, but like I said I was ready to change out the ball anyway.

So what do you think?

Thanks

[Big Daddy Roth]

You figure this out, you let me know. I have the same problem with my AAZ B3

[Powered by Spearco]

Once the engine has started and the light comes on due to low coolant. You have to turn off the ingnition to reset the light after the coolant level is topped up.
If it still flashes, it could be the sensor itself, wiring, relay, or the voltage stabillizer.
I just went through a simular experence.

[SolarSteve]

Once the engine has started and the light comes on due to low coolant. You have to turn off the ingnition to reset the light after the coolant level is topped up.
If it still flashes, it could be the sensor itself, wiring, relay, or the voltage stabillizer.
I just went through a simular experence.

That makes sence because last night when I started it to go home the light no longer flashed.  I guess I need to start looking for a coolant leak.

My new coolant ball arrived today, GAP is FAST!!  So at least I will easily be able to see how much coolant is in there.

[smutts]

That low coolant sensor has saved me at least two engines. It is well worth sorting out and keeping.

[SolarSteve]

It seems most stuff pops up when I am short for time and trying to get somewhere.  After thinking about this for a while I remember when I first got the car and it had oil and coolant leaks (mostly from the plastic T-stat housing which I switch to an aluminum one).  As I was working to get them all sealed the low coolant light came on and I topped it off but the light was still flashing.  I shut the engine off to prevent any damage and checked everything over.  When I couldn't find any problems I re-started the engine and the light stopped.

I found a coolant connection that was a little wet and took care of it.  I will keep my eye on it as well as the level of coolant (after I swap balls) and hopefully the light won't come back on!

[smutts]

I topped it off but the light was still flashing

Don't panic! that is normal, it is bit of a pain if the coolant level has got to the point where movement causes the coolant thingymajig to trigger the warning light because it latches on.
It's silly, because either you flick the ignition off a moment to reset it, whilst moving with or without the steering lock engaging! Or you just assume that there is enough coolant, it's just a little low. Then BANG and expense to prove otherwise.

[SolarSteve]

I topped it off but the light was still flashing

Don't panic! that is normal, it is bit of a pain if the coolant level has got to the point where movement causes the coolant thingymajig to trigger the warning light because it latches on.
It's silly, because either you flick the ignition off a moment to reset it, whilst moving with or without the steering lock engaging! Or you just assume that there is enough coolant, it's just a little low. Then BANG and expense to prove otherwise.

Agreed.

I should have remember to just turn it off topped it off and restarted it, but at that time I was going to be last and couldn't see anything major.  The bright side is I now have a nice new coolant ball!

[Big Daddy Roth]

I thought my problem was the coolant level sensor as well. But I unplugged it and jumpped the two wires together, light still flashed. So that's not my problem. My temp and fuel guages appear to read correct, so I don't think it could be the voltage stablizer.

[SolarSteve]

I believe it will also flash under an over-heat condition.

Mabey a temp sensor has failed?

[fatmobile]

If the ground wire for the sensor is corroded or disconnected the voltage will go high.

 That will trigger the light.
 IF you can pull back the rubber boot (oh wait no rubber boot on the coolant ball style) and check the voltage while it's plugged in that will give you some info on how high it is reading across the sensor.

[DieselBalz]

I know its an old thread, but just wanted to point out how awesome the search feature is.

I usually warm the Eco up in the morning for about five to ten minutes before I head into work. Thursday I got in it after it warming up and the coolant light was flashing but the temp gauge was normal. Not having time to diagnose the problem, I shut it down and took the F150 to work for the next few days.

Got up this morning full on thinking the thermo was bad, but decided to hop on the GTD forums and see what others had to deal with when the light was flashing. Low coolant. Topped it off and unplugged/plugged the sensor started it up, no light. Awesome, but, why am I loosing coolant? After closer inspection, a small leak is coming from the ball.

I have been wanting to change that thing as it is so weathered I cant tell how much coolant is in it without actually opening it. So, thanks GTD for keeping me from getting all dirty for no reason, off to GAP to order a new ball.

[8v-of-fury]

I know its an old thread, but just wanted to point out how awesome the search feature is.

I usually warm the Eco up in the morning for about five to ten minutes before I head into work. Thursday I got in it after it warming up and the coolant light was flashing but the temp gauge was normal. Not having time to diagnose the problem, I shut it down and took the F150 to work for the next few days.

Got up this morning full on thinking the thermo was bad, but decided to hop on the GTD forums and see what others had to deal with when the light was flashing. Low coolant. Topped it off and unplugged/plugged the sensor started it up, no light. Awesome, but, why am I loosing coolant? After closer inspection, a small leak is coming from the ball.

I have been wanting to change that thing as it is so weathered I cant tell how much coolant is in it without actually opening it. So, thanks GTD for keeping me from getting all dirty for no reason, off to GAP to order a new ball.

You need to warm your car up for 10 minutes in FLA? WOW. lmao. I don't think my car gets that here in negative temperatures! haha

[DieselBalz]

Lol, I probably don't need to warm it up for that long, but I like to. This way if I have to jump on the go pedal to get on the interstate, I'm not throwin 20 psi into a cold motor. Also I went ahead and purchased a low temmp (for hot weather) tstat, can of lubromolly radiator flush, and three bottles of g11, as well as the new exansion tank.

Figured if I was going to have to drain the coolant, I might as well freshen up the whole cooling system, put the right coolant in it, flush it, and I'll be ready for summer.