Low Coolant Message

2000 Silhouette, 3.4, I get a low coolant message when I first start my van, which slowly goes off after a little while of driving,but it seems to be staying on longer and longer as the outside temp drops lower. check the bottle and not low. This issue is driving my wife nuts which in turn is driving me nuts. I was told that I just needed to reset the sensor but he didn't know how to do it. Is that possible or is it just a line to keep me returning the van to him, as we purchsed the van less than 1 month ago from him. Is ther ea way to reset the sensor or do I just need to buy a new coolant level sensor.

the low coolant sensor is not in the bottle [resevoir] it is 3" below the radiator cap. loosen the radiator cap [easier said than done]and see if any coolant comes out .if not then take the rad cap off and see how far down the coolant is.if it is not up by the cap then fill it up and put the cap back on.see if the low coolant light stays off.if it comes back on let it cool down and open the rad cap again and see where the coolant is if it is low again .i would put a new rad cap on and see if this fixes it.a bad rad cap will not let the radiator pull coolant from the resevoir when it needs it. and it will loose cooolant down the side of the radiator.do not open a hot radiator cap -let it cool down..........

I have to say that the low coolant sensor has been an issue for my engine too. When the head gaskets went bad, I had a lot of overheating and the sensor light would come on often. The level never got low in the rad, but I guessed that air bubbles in there made the sensor activate.

I replaced the head gaskets on that engine and still the sensor would go off at random times. I replaced the sensor and the problem went away for about 1 year. That engine then broke the cam shaft and I replaced the engine with a rebuilt.

Again, I had the sensor light come on from time to time, mostly when the new engine was hot. I also switched to green coolant when I installed the new engine, and thought perhaps that might have been the problem with the sensor.

Bottom line for me now (after about 8000 miles on new engine) is the low coolant light still comes on once in a while, the coolant is never low anymore, and I am not shelling out another $50 bucks for another sensor.
I have learned that the low coolant sensor does not connect to any aspect of the computer other than the dash light. If you disconnect the cable from the sensor, the light will go out, and no codes will set.

I have a new engine and at least for a year or so I have confidence that there is no underlying reason for the low coolant light to come on. I would not suggest anyone else disconnect that sensor, I'm just passing along the information. I think the sensor is overly sensitive to air in the system and comes on needlessly -- You need to be sure the coolant level isn't really low by opening the radiator cap and checking it. Also try to sniff the engine for coolant leaks--if there is any coolant leaking out, you should get a whiff of it.

I have been getting a low coolant message for about 3 weeks now. Check the coolant level and it is fine. Been getting the message on startup and depending on outside temp. stays on from 5 to 20 minutes, then goes outand stays out till next startup. Talked to the dealer where I brought the van and he says the sensor needs to be reset, but didn't know the procedure to do it. Is he just pulling my leg on resetting the sensor? Or is the message telling me that I may need to replace the sensor.

I am not familiar with your particular vehicle. On other vehicles there is a sensor in the bottom of the coolant resivoir. These can become contaminated with sludge or just go bad.

The coolant sensor is located on the passenger side of the radiator, about 6 inches below the filler cap. If you remove the cable from the sensor, the light will go off. There is no connection between the sensor and anything other than the instrument warning light--meaning it will not set any codes.

The sensor is a conductivity type, so when its wet the circuit passes enough current to hold the light circuit turned off. If it can't pass enough current (because its not wet), then the lamp circuit is able to turn on and ground the bulb, completing the circuit to light the bulb.

If you have bubbles in your coolant, or if the coolant is low, it will come on. I'm not sure I trust mine because it seems to come on frequently, but the coolant is never low. It could be that there are some bubbles in there, but I've never had any other problem with this new engine.

if the rad is low(thats below the sensor) the dash lamp will turn on showing the coolant is low. the over flow tank should be low or below the full cold line when the light is on. you can remove the rad cap when the rad is "cold"and have a look. the coolant should be full in the rad. the rad cap may be the problem in not letting coolant flow both in and out of the rad. the cap is a ACDELCO Part # RC27 {replaces RC36B #10409635, 25060216, RC36B}
CAP,RAD at 16 lbs $7-10 range. hopefully your gaskets are good and not letting the cooling and oil mix or leak. keep us updated and we sould be able to get this resolved for you. Trueman

Ok - Here is the overall issue. The Coolant level is where it is supposed to be. I have no leaks and the oil/coolant is not mixing. The light comes on whenever I start the van, and goes off after 5 to 20 mintues depending on outside temp. The colder it is outside the longer the light is on. Once the light goes off it stays off until I shut the van off, and if I start the van right after turning it off the light comes on, repeating the above issue over and over again. The carlot I got the van from told me that the sensor needs to be reset, but he didn't know how to do it. I think he was pulling me leg on resetting the sensor as the issue started just 1 week after getting the van, and he didn't want me to return the van to him. So my question is can the sensor be reset, if so what is the procedure to do it, or is the sesnor just going bad, and needs to be replaced.

Not to belittle the point, but I've described exactly what the sensor is and how it works. The is no reset, there is no loose connection (light goes off when disconnected), there is no connection to the car computer. Its just a sensor with a built in switch circuit that lights the dash light.

You can buy a new one ($50+), you can unplug the current one (light goes out), or you can just ignore it. You can not reset anything.
John

I have been getting a low coolant message for about 3 weeks now.

Your prior post on this issue and new post have been merged. Please try to keep one thread only on the same issue otherwise it may cause confusion and redundant replies.

i know of no way to reset the low-coolant sensor either if the sensor acts up when it is cold then the sensor is bad .it could have a crack in it and the cold makes it not sense the coolant. if the dealer won't put it in then let him pay for it put in. if he can reset it let him -just make sure he does not just unplug it.....i guess i'm still on topic?

i no on a p.a. low coolant sensor is on passenger side in the side of radiator

Thanks to all those to replied to my question. I guess I am buying a new sensor. Sorry for the double posting, my wife didn't know I was posting that question, therefore posted it herself.

I believe my low coolant sensor got contaminated from a failed intake manafold gasket which causes the light to remain on.
I eventually replaced the low coolant sensor ( twice, once with an aftermarket sensor which gave the sme false indication and then with a GM sensor) The GM sensor worked corectly for awhile and then the light came on , then went off of a few weeks and now comes on again.
I believe it is caused by remainig contamination in the coolant fluid.
The coolant level is always OK!

You most likely have air in the system. I used a spill free funnel and inclined the front of the vehicle and get almost all of the air out. The light will go off even when coolant is around it if there is air in the system. The bleeder valves only work most of the air out. Hope this helps.

I had the same issues with a false low coolant light.
I researched this question and found in other forums that when the low coolant sensor gets contaminated , it can no longer conduct and thus give the low coolant indication.
I replaced my original sensor but found that shortly thereafter the new sensor got contaminated and it too gives a false reading.
This all started when the intake manifold gasket went bad (replaced twice) and this likely caused contamination in the cooling system, that new antifreeze did not cure.
i also found a procedure suggesting to remove the sensor and clean it with a brush. it will then work again, for awhile, until it gets contaminated again.

Thanks for the suggestion on the air bubbles, i wil give it a try