low coolant light
Thread Starter
Heel & Toe
Joined: Sep 2002
Posts: 23
Likes: 0
From: Toronto Ontario
low coolant light
I have an 89 and have been having trouble with the low coolant light. It is not a consistant problem. Somedays the light is on the entire time and other days it is on and off.
I had the sensor replaced but that didn't help.
The cap has been replaced, the coolant flushed, the radiator has been pressure tested. This was all done when I had to replace the water pump. All of which have made no difference.
I am continuely checking the level in the radiator and have to top it up on occasion.
I don't understand why the light comes on when the coolant level is always over the sensor.
Any suggestions would be greatly appreciated.
Thanks
Dutchie
I had the sensor replaced but that didn't help.
The cap has been replaced, the coolant flushed, the radiator has been pressure tested. This was all done when I had to replace the water pump. All of which have made no difference.
I am continuely checking the level in the radiator and have to top it up on occasion.
I don't understand why the light comes on when the coolant level is always over the sensor.
Any suggestions would be greatly appreciated.
Thanks
Dutchie
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Originally Posted by Dutchie
I am continuely checking the level in the radiator and have to top it up on occasion.
You have air pockets trapped in your system, hence the intermittent low coolant light.
You need to let the car idle to operating temps.
Periodically squeeze the upper radiator hose with a shop rag around your hand. When the hose is no longer rock hard, the thermostat has opened, and coolant is now circulating.
Have someone inside the car raise the idle to 1500 RPM or more and hold it there. Then carefully remove the radiator cap, fill the radiator, and install the cap before the person inside the car lets the idle back down.
Holding the idle RPM's up causes the coolant level in the radiator to drop further down.
This "packs" your radiator full.
Driver the car and repeat the process over the next several days untill the coolant level remainst constant, and air pockets have been expelled or "burped" out of the system.
Obvisouly make sure your coolant is not leaking from somewhere.
Drifting
Joined: May 2002
Posts: 1,581
Likes: 2
From: The Motor City
This could be the sign of a very big problem... I know because that's what happened to my '89.
For the longest time, my coolant light would sometimes come on, then sometimes not. And there was no rhym or reason for it. And I monitored the coolant level constantly and I ALWAYS walked away from the car with a full cooling system. Yet after a couple of days of driving, the light would come back on, and I couldn't figure out why. Until one day when I fired the car up and white pillowing smoke came out the exhaust - BLOWN HEAD GASKET! What I think was happening was that my car had a very very small coolant leak. Nothing that caused an overheating condition, but that just got worse over time until it finally let go.
Don't get me wrong, I'm not saying you have a head gasket leak! That was just my experience. This could just be a simple fix.
The first suggestion I would make is to ensure that the cooling system is fully packed. Because the radiator in a C4 sits below the engine, you can't fill the cooling system at the radiator as you would in a 'normal' vehicle. Follow the Helms manual on packing the cooling system. If you don't have the manual, the procedure is as follows:
1. Fill the cooling system to capacity at the radiator
2. Start the vehicle with the radiator cap off
3. Rev the engine to approximately 1500rpm and hold the RPMs at that speed
4. The coolant level in the radiator will drop as the water pump draws in coolant to pack the system.
5. With the engine at 1500 RPM add additional coolant to fill the radiator.
6. Replace the radiator cap, then allow the engine revs to return to idle.
Once you've done this, the cooling system should be properly packed. Because of this, it is important that you DO NOT CHECK THE COOLANT LEVEL AT THE RADIATOR!!! The coolant level in these cars should ALWAYS be checked at the overflow tank. If you take the radiator cap off the car, you will "unpack" the system, and you'll have to pack it all over again.
Another suggestion I would make would be to replace your thermostat with a high-flow unit that has a steam-hole in it (this would be a good time to go with a 160deg unit too). This will make it alot easier to pack the cooling system.
Good luck!
For the longest time, my coolant light would sometimes come on, then sometimes not. And there was no rhym or reason for it. And I monitored the coolant level constantly and I ALWAYS walked away from the car with a full cooling system. Yet after a couple of days of driving, the light would come back on, and I couldn't figure out why. Until one day when I fired the car up and white pillowing smoke came out the exhaust - BLOWN HEAD GASKET! What I think was happening was that my car had a very very small coolant leak. Nothing that caused an overheating condition, but that just got worse over time until it finally let go.
Don't get me wrong, I'm not saying you have a head gasket leak! That was just my experience. This could just be a simple fix.
The first suggestion I would make is to ensure that the cooling system is fully packed. Because the radiator in a C4 sits below the engine, you can't fill the cooling system at the radiator as you would in a 'normal' vehicle. Follow the Helms manual on packing the cooling system. If you don't have the manual, the procedure is as follows:
1. Fill the cooling system to capacity at the radiator
2. Start the vehicle with the radiator cap off
3. Rev the engine to approximately 1500rpm and hold the RPMs at that speed
4. The coolant level in the radiator will drop as the water pump draws in coolant to pack the system.
5. With the engine at 1500 RPM add additional coolant to fill the radiator.
6. Replace the radiator cap, then allow the engine revs to return to idle.
Once you've done this, the cooling system should be properly packed. Because of this, it is important that you DO NOT CHECK THE COOLANT LEVEL AT THE RADIATOR!!! The coolant level in these cars should ALWAYS be checked at the overflow tank. If you take the radiator cap off the car, you will "unpack" the system, and you'll have to pack it all over again.
Another suggestion I would make would be to replace your thermostat with a high-flow unit that has a steam-hole in it (this would be a good time to go with a 160deg unit too). This will make it alot easier to pack the cooling system.
Good luck!
Last edited by TheCorvetteKid; Aug 14, 2006 at 08:35 PM.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
[QUOTE=TheCorvetteKid]This could be the sign of a very big problem... I know because that's what happened to my '89.
For the longest time, my coolant light would sometimes come on, then sometimes not. And there was no rhym or reason for it. And I monitored the coolant level constantly and I ALWAYS walked away from the car with a full cooling system. Yet after a couple of days of driving, the light would come back on, and I couldn't figure out why. Until one day when I fired the car up and white pillowing smoke came out the exhaust - BLOWN HEAD GASKET! What I think was happening was that my car had a very very small coolant leak. Nothing that caused an overheating condition, but that just got worse over time until it finally let go.
Don't get me wrong, I'm not saying you have a head gasket leak! That was just my experience. This could just be a simple fix.
The first suggestion I would make is to ensure that the cooling system is fully packed. Because the radiator in a C4 sits below the engine, you can't fill the cooling system at the radiator as you would in a 'normal' vehicle. Follow the Helms manual on packing the cooling system. If you don't have the manual, the procedure is as follows:
1. Fill the cooling system to capacity at the radiator
2. Start the vehicle with the radiator cap off
3. Rev the engine to approximately 1500rpm and hold the RPMs at that speed
4. The coolant level in the radiator will drop as the water pump draws in coolant to pack the system.
5. With the engine at 1500 RPM add additional coolant to fill the radiator.
6. Replace the radiator cap, then allow the engine revs to return to idle.
Once you've done this, the cooling system should be properly packed. Because of this, it is important that you DO NOT CHECK THE COOLANT LEVEL AT THE RADIATOR!!! The coolant level in these cars should ALWAYS be checked at the overflow tank. If you take the radiator cap off the car, you will "unpack" the system, and you'll have to pack it all over again.
Another suggestion I would make would be to replace your thermostat with a high-flow unit that has a steam-hole in it (this would be a good time to go with a 160deg unit too). This will make it alot easier to pack the cooling system.
Good luck
For the longest time, my coolant light would sometimes come on, then sometimes not. And there was no rhym or reason for it. And I monitored the coolant level constantly and I ALWAYS walked away from the car with a full cooling system. Yet after a couple of days of driving, the light would come back on, and I couldn't figure out why. Until one day when I fired the car up and white pillowing smoke came out the exhaust - BLOWN HEAD GASKET! What I think was happening was that my car had a very very small coolant leak. Nothing that caused an overheating condition, but that just got worse over time until it finally let go.
Don't get me wrong, I'm not saying you have a head gasket leak! That was just my experience. This could just be a simple fix.
The first suggestion I would make is to ensure that the cooling system is fully packed. Because the radiator in a C4 sits below the engine, you can't fill the cooling system at the radiator as you would in a 'normal' vehicle. Follow the Helms manual on packing the cooling system. If you don't have the manual, the procedure is as follows:
1. Fill the cooling system to capacity at the radiator
2. Start the vehicle with the radiator cap off
3. Rev the engine to approximately 1500rpm and hold the RPMs at that speed
4. The coolant level in the radiator will drop as the water pump draws in coolant to pack the system.
5. With the engine at 1500 RPM add additional coolant to fill the radiator.
6. Replace the radiator cap, then allow the engine revs to return to idle.
Once you've done this, the cooling system should be properly packed. Because of this, it is important that you DO NOT CHECK THE COOLANT LEVEL AT THE RADIATOR!!! The coolant level in these cars should ALWAYS be checked at the overflow tank. If you take the radiator cap off the car, you will "unpack" the system, and you'll have to pack it all over again.
Another suggestion I would make would be to replace your thermostat with a high-flow unit that has a steam-hole in it (this would be a good time to go with a 160deg unit too). This will make it alot easier to pack the cooling system.
Good luck!
[/Q"Burp" the system. Good post.
