Low Coolant problem/question
#1
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My '99 Firehawk has been showing me the low coolant light off and on for about two weeks now and in the beginning it would turn off if I was driving on the freeway or something like that, however, it hasn't turned off for several days now regardless of how I was driving. The engine is still running at normal operating temp despite this.
Every time I check the radiator it's always full and so is the reservoir. I have squeezed the hoses while the engine is running to try and force out any possible air pockets or to push some coolant into the block but, that doesn't seem to help. Here's the kicker though, after the car has been running and has gotten up to operating temp I can go and take the radiator cap off without any problem and coolant doesn't spew out as it normally would. The coolant is still hot though and it seems to be circulating but, I don't see any fluid coming out of the hose/opening at the top of the radiator just under the cap as I did when I replaced the water pump on it with a brand new, not refurbished, water pump about 6 months ago and was bleeding the system.
My thought at this point is that the issue could possibly be that the thermostat (SLP 160º stat) could be bad?! It's several years old so it could be that but, I'm not sure. There seems to be a lack of pressure in the system and I don't know if a bad thermostat would cause that or if it was something else. I've never heard of a thermostat going bad but, I don't know what else it could possibly be. Any thoughts or ideas? Thanks!
Every time I check the radiator it's always full and so is the reservoir. I have squeezed the hoses while the engine is running to try and force out any possible air pockets or to push some coolant into the block but, that doesn't seem to help. Here's the kicker though, after the car has been running and has gotten up to operating temp I can go and take the radiator cap off without any problem and coolant doesn't spew out as it normally would. The coolant is still hot though and it seems to be circulating but, I don't see any fluid coming out of the hose/opening at the top of the radiator just under the cap as I did when I replaced the water pump on it with a brand new, not refurbished, water pump about 6 months ago and was bleeding the system.
My thought at this point is that the issue could possibly be that the thermostat (SLP 160º stat) could be bad?! It's several years old so it could be that but, I'm not sure. There seems to be a lack of pressure in the system and I don't know if a bad thermostat would cause that or if it was something else. I've never heard of a thermostat going bad but, I don't know what else it could possibly be. Any thoughts or ideas? Thanks!
#2
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maybe the sensor is just going bad? if your not overheating and the only real indication of a problem is the low coolant light then i see it as you have two options: replace the low coolant sensor (i think located on the lower passenger side of the radiator, or just unplug it. Either way i think that is your only problem if it is not overheating then it is not broke and if it aint broke don't fix it...
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maybe the sensor is just going bad? if your not overheating and the only real indication of a problem is the low coolant light then i see it as you have two options: replace the low coolant sensor (i think located on the lower passenger side of the radiator, or just unplug it. Either way i think that is your only problem if it is not overheating then it is not broke and if it aint broke don't fix it...
Thanks for the response!
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What about the seeming lack of pressure in the system? I shouldn't be able to remove the radiator cap without coolant spewing everywhere when it's at operating temp and I can do that with no problem? Any thoughts on that issue?
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On the sensor:
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
![](http://www.familycar.com/Classroom/Images/PressureTester.jpg)
#7
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On the sensor:
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
![](http://www.familycar.com/Classroom/Images/PressureTester.jpg)
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
![](http://www.familycar.com/Classroom/Images/PressureTester.jpg)
Thank you to everyone that contributed, I really appreciate the help! I'll let you know how it turns out.
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
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#9
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On the sensor:
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
![](http://www.familycar.com/Classroom/Images/PressureTester.jpg)
You have a common issue, do this instead to save some $, take the old one out and CLEAN off the tip, it just gets funked up and throws the bum signal. Should work unless the unit is bad which is often not the case. OR, do as others have done and UNPLUG that biotch! I've cleaned mine before too and it worked for me.....
On the pressure issue:
Take it somewhere where they have one of those pump up pressure testers, this will tell if your cooling system is holding pressure or has a leak.
![](http://www.familycar.com/Classroom/Images/PressureTester.jpg)
#10
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You could just have a bad radiator cap. They have adapters for those pressure testers that fit various types of radiator caps. In fact, you can rent the kit at Autozone.
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I found a new GM radiator cap for $7 plus shipping so I was going to replace that anyway for that price. Why not, right?!?!
#12
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#13
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I just got done pulling off the old sensor and it was all gunked up so I cleaned it out and re-installed. I replaced the coolant that leaked out when I pulled the sensor off and ran the car for a bit and it worked fine. The low coolant light on the dash never came back on and after the car got up to normal operating temp I tried to take the radiator cap off to check it and coolant started spewing out so it seems that the issue was just the sensor being gunked up... at least for now. Thanks to CajunFirehawk for suggesting cleaning out the sensor first! That was certainly much easier on the wallet than having to spend $40-$50 needlessly!
And thanks again to everyone else that contributed with their great thoughts and ideas as well. It is much appreciated!!!
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
And thanks again to everyone else that contributed with their great thoughts and ideas as well. It is much appreciated!!!
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
![Cheers!!](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_cheers.gif)
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