Low Coolant Light
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Joined: Feb 2005
Posts: 61
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From: Mahwah NJ
Low Coolant Light
I had the coolant flushed on my 1995 Coupe by a local shop, and now for the 1st few minutes of driving and every once and a while while I drive, the LOW COOLANT light comes on. I have checked the level in reserve tank at start up, when warm, when light is on, and off and it is within the lines. Anybody lend a hand as to why?
It never had come on before flush.
Thanks..Angelo
It never had come on before flush.
Thanks..Angelo
Melting Slicks
Joined: Jan 2002
Posts: 2,531
Likes: 35
From: Lecanto Florida
I'll bet my next annuity check that the shop didn't get the system filled all the way. My light was coming on also. Here's quick and dirty way of filling it up.
Jack up the front end a bit.
Cold engine, take the radiator cap off.
Make sure the overflow tank is at the level is should be.
Start the engine and let it idle till it starts to get hot. You might see the level of the water start to raise, so reach over and turn the throttle body lever so the revs come up. You'll notice that the water level will drop as the revs raise. The water is going into the engine and filling the space where there was air.
Have a container of 50/50 mix handy so you can reach it without letting the revs drop. Fill the radiator with the 50/50 mix as much as it will take without coming out the filler hole. When it's filled, reach over (still keeping revs up) and tighten down the radiator cap.
Let the revs drop down to normal. That should get all the air out and you shouldn't see the "Low Coolant" light anymore.
Jack up the front end a bit.
Cold engine, take the radiator cap off.
Make sure the overflow tank is at the level is should be.
Start the engine and let it idle till it starts to get hot. You might see the level of the water start to raise, so reach over and turn the throttle body lever so the revs come up. You'll notice that the water level will drop as the revs raise. The water is going into the engine and filling the space where there was air.
Have a container of 50/50 mix handy so you can reach it without letting the revs drop. Fill the radiator with the 50/50 mix as much as it will take without coming out the filler hole. When it's filled, reach over (still keeping revs up) and tighten down the radiator cap.
Let the revs drop down to normal. That should get all the air out and you shouldn't see the "Low Coolant" light anymore.
Le Mans Master
Joined: Aug 2002
Posts: 7,441
Likes: 421
From: Ventura County, CA
St. Jude Donor '05 thru '24
Originally Posted by CREWZIN
I'll bet my next annuity check that the shop didn't get the system filled all the way. My light was coming on also. Here's quick and dirty way of filling it up.
Jack up the front end a bit.
Cold engine, take the radiator cap off.
Make sure the overflow tank is at the level is should be.
Start the engine and let it idle till it starts to get hot. You might see the level of the water start to raise, so reach over and turn the throttle body lever so the revs come up. You'll notice that the water level will drop as the revs raise. The water is going into the engine and filling the space where there was air.
Have a container of 50/50 mix handy so you can reach it without letting the revs drop. Fill the radiator with the 50/50 mix as much as it will take without coming out the filler hole. When it's filled, reach over (still keeping revs up) and tighten down the radiator cap.
Let the revs drop down to normal. That should get all the air out and you shouldn't see the "Low Coolant" light anymore.
Jack up the front end a bit.
Cold engine, take the radiator cap off.
Make sure the overflow tank is at the level is should be.
Start the engine and let it idle till it starts to get hot. You might see the level of the water start to raise, so reach over and turn the throttle body lever so the revs come up. You'll notice that the water level will drop as the revs raise. The water is going into the engine and filling the space where there was air.
Have a container of 50/50 mix handy so you can reach it without letting the revs drop. Fill the radiator with the 50/50 mix as much as it will take without coming out the filler hole. When it's filled, reach over (still keeping revs up) and tighten down the radiator cap.
Let the revs drop down to normal. That should get all the air out and you shouldn't see the "Low Coolant" light anymore.
Perfect.
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by CREWZIN
Thanks. 
Whoa! That is way wrong advise for a 95 LT1. Don't do any of that, it is waste of time and won't ge the air out. Look at the top of the Tstat housing (passenger side front of motor by the throttle body) and you will see a brass slotted head bleeder valve. THAT IS THE ONLY WAY TO PURGE THE AIR OUT OF YOUR COOLANT SYSTEM. And if you don't use the bleeder screw you will never get the air out and continue to have problems. Wrap some rags around it, bleed it cold and then again after reaching operating temps, then refill surge tank and you are good to go.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
I'm betting that the shop did not purge air from the system by using the bleed valve. This is an important step to insure that air pockets are out of the system.
The surge tank has to be filled so that the water level is right at the base of the filler neck.
Once you have the system purged of air, run the motor at about 1200 RPM and fill the tank. Replace the presure cap and you can shut the motor off.
Fill the overflow tank to the HOT line and watch the level over a few days and refill as needed.
The service manual also states that after a flush and refill is done, you should let the motor go thru three completel cycles of going from cold to operating temp and back to cold berfore doing any full-throttle operation. This cycle step will also help to purge any remaining air from the system.
The surge tank has to be filled so that the water level is right at the base of the filler neck.
Once you have the system purged of air, run the motor at about 1200 RPM and fill the tank. Replace the presure cap and you can shut the motor off.
Fill the overflow tank to the HOT line and watch the level over a few days and refill as needed.
The service manual also states that after a flush and refill is done, you should let the motor go thru three completel cycles of going from cold to operating temp and back to cold berfore doing any full-throttle operation. This cycle step will also help to purge any remaining air from the system.
Melting Slicks
Joined: Jan 2002
Posts: 2,531
Likes: 35
From: Lecanto Florida
Originally Posted by aminnich
Whoa! That is way wrong advise for a 95 LT1. Don't do any of that, it is waste of time and won't ge the air out.
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Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by c4cruiser
I'm betting that the shop did not purge air from the system by using the bleed valve. This is an important step to insure that air pockets are out of the system.
The surge tank has to be filled so that the water level is right at the base of the filler neck.
Once you have the system purged of air, run the motor at about 1200 RPM and fill the tank. Replace the presure cap and you can shut the motor off.
Fill the overflow tank to the HOT line and watch the level over a few days and refill as needed.
The service manual also states that after a flush and refill is done, you should let the motor go thru three completel cycles of going from cold to operating temp and back to cold berfore doing any full-throttle operation. This cycle step will also help to purge any remaining air from the system.
The surge tank has to be filled so that the water level is right at the base of the filler neck.
Once you have the system purged of air, run the motor at about 1200 RPM and fill the tank. Replace the presure cap and you can shut the motor off.
Fill the overflow tank to the HOT line and watch the level over a few days and refill as needed.
The service manual also states that after a flush and refill is done, you should let the motor go thru three completel cycles of going from cold to operating temp and back to cold berfore doing any full-throttle operation. This cycle step will also help to purge any remaining air from the system.
That's what I said, or hope I said. Also, the low coolant probe is not in the overflow tank, it is in the surge tank (right side just in front of the engine cowl).
