change/flush cooling system
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
Granted that it pretty easy when the temps are above freezing, but the trick to not to trap air in the system.
Start off by draining the old fluid through the valve on the back of the radiator passenger side. Next, if you still have a Newish stock T stat in place, pull it, drill a 1/8" hole on the out flange, then reinstall the T stat with the new drilled hole top dead center back in the housing. This small hole will prevent air from being trapped in the system. If the T stat is old (couple or years or more), then change it out to a new T stat with vent channel. The water pump T stat is easy to change since it on the front of the pump housing, and the bolts get torqued to 11ft lbs.
The system holds about 12.6 quarts of water/Dex-Cool mix. So for fluids, pick up two gallons of Dex-Cool (straight) and 6 gallons of distilled water from any grocery store.
With the fluid drained, and a vent channel through the T stat so the system will not trap air, fill the system up with straight distilled water (again, do this when the temps are not going to drop below freezing), then go drive the car for a day/ or at least a few hours.
Now drain the radiator again, and this time, Take a look at the water and if it pretty murky still, then fill again with straight distilled water and drive the car for another day/few hours at least, then drain again.
Interjection here, If the tank looks pretty ugly with side wall film, its pretty easy to clean. Just pull the tank since you have the system drained, fill the tank up with crushed ice, and ice water, put screw the cap back on, then shake the tank hard so the ice scraps off the film inside the tank.
When you go to fill the car back up, you need to first add 6.1 quarts of dex-cool, then finish the fill off with distilled water. There will still be water in the system after the drain, so if you just try to fill with 50/50 mix, the dex/cool mix level will be off (more water than dex-cool).
As for the tank full fill level, on the front side of the tank (head light side) there is a line across the tank that is the full fill mark. So the tank only get filled to the line, leaving the tank about half empty.
As for the extra half gallon of straight Dex-cool you have left over, match it distilled water, them mark the bottle 50/50 for top offs if needed.
And to add, with the small vent hole now in the T stat, filling the system back up will be snap (no pressure/vacuum locking).
T stat with vent channel,
T stat without vent channel that you would want to drill a small vent channel instead.
Start off by draining the old fluid through the valve on the back of the radiator passenger side. Next, if you still have a Newish stock T stat in place, pull it, drill a 1/8" hole on the out flange, then reinstall the T stat with the new drilled hole top dead center back in the housing. This small hole will prevent air from being trapped in the system. If the T stat is old (couple or years or more), then change it out to a new T stat with vent channel. The water pump T stat is easy to change since it on the front of the pump housing, and the bolts get torqued to 11ft lbs.
The system holds about 12.6 quarts of water/Dex-Cool mix. So for fluids, pick up two gallons of Dex-Cool (straight) and 6 gallons of distilled water from any grocery store.
With the fluid drained, and a vent channel through the T stat so the system will not trap air, fill the system up with straight distilled water (again, do this when the temps are not going to drop below freezing), then go drive the car for a day/ or at least a few hours.
Now drain the radiator again, and this time, Take a look at the water and if it pretty murky still, then fill again with straight distilled water and drive the car for another day/few hours at least, then drain again.
Interjection here, If the tank looks pretty ugly with side wall film, its pretty easy to clean. Just pull the tank since you have the system drained, fill the tank up with crushed ice, and ice water, put screw the cap back on, then shake the tank hard so the ice scraps off the film inside the tank.
When you go to fill the car back up, you need to first add 6.1 quarts of dex-cool, then finish the fill off with distilled water. There will still be water in the system after the drain, so if you just try to fill with 50/50 mix, the dex/cool mix level will be off (more water than dex-cool).
As for the tank full fill level, on the front side of the tank (head light side) there is a line across the tank that is the full fill mark. So the tank only get filled to the line, leaving the tank about half empty.
As for the extra half gallon of straight Dex-cool you have left over, match it distilled water, them mark the bottle 50/50 for top offs if needed.
And to add, with the small vent hole now in the T stat, filling the system back up will be snap (no pressure/vacuum locking).
T stat with vent channel,
T stat without vent channel that you would want to drill a small vent channel instead.
Intermediate
Joined: Feb 2014
Posts: 34
Likes: 0
From: California
Granted that it pretty easy when the temps are above freezing, but the trick to not to trap air in the system. Start off by draining the old fluid through the valve on the back of the radiator passenger side. Next, if you still have a Newish stock T stat in place, pull it, drill a 1/8" hole on the out flange, then reinstall the T stat with the new drilled hole top dead center back in the housing. This small hole will prevent air from being trapped in the system. If the T stat is old (couple or years or more), then change it out to a new T stat with vent channel. The water pump T stat is easy to change since it on the front of the pump housing, and the bolts get torqued to 11ft lbs. The system holds about 12.6 quarts of water/Dex-Cool mix. So for fluids, pick up two gallons of Dex-Cool (straight) and 6 gallons of distilled water from any grocery store. With the fluid drained, and a vent channel through the T stat so the system will not trap air, fill the system up with straight distilled water (again, do this when the temps are not going to drop below freezing), then go drive the car for a day/ or at least a few hours. Now drain the radiator again, and this time, Take a look at the water and if it pretty murky still, then fill again with straight distilled water and drive the car for another day/few hours at least, then drain again. Interjection here, If the tank looks pretty ugly with side wall film, its pretty easy to clean. Just pull the tank since you have the system drained, fill the tank up with crushed ice, and ice water, put screw the cap back on, then shake the tank hard so the ice scraps off the film inside the tank. When you go to fill the car back up, you need to first add 6.1 quarts of dex-cool, then finish the fill off with distilled water. There will still be water in the system after the drain, so if you just try to fill with 50/50 mix, the dex/cool mix level will be off (more water than dex-cool). As for the tank full fill level, on the front side of the tank (head light side) there is a line across the tank that is the full fill mark. So the tank only get filled to the line, leaving the tank about half empty. As for the extra half gallon of straight Dex-cool you have left over, match it distilled water, them mark the bottle 50/50 for top offs if needed. And to add, with the small vent hole now in the T stat, filling the system back up will be snap (no pressure/vacuum locking). T stat with vent channel, T stat without vent channel that you would want to drill a small vent channel instead.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
Yes, that brass button piece through the through the small channel on the bottom right of the flange in your photo is the vent channel to prevent pressure/suction locking as the system is being refilled.
When you install the T stat (installs in the cover, then the cover with T stat is bolted to the front of the pump), make sure to have the brass button piece in the flange channel set top dead center up of the Pump housing before reinstalling hose attachment cover plate. The tab on the T stat rubber outer gasket should have it set correctly when the tab is mated to the corresponding channel on the pump, but if not, you may need to spin the rubber gasket on the T stat to potion the tab correctly, and index the T stat flange vent TDC.
And again, 11ft lb total torque on the T stat water cover bolts, so start off with hand tight on the bolts to make sure that you have the T stat with outer rubber ring seated correctly in the pump face recess channel for it, torque to say 5ft lbs on each bolt, then final torque to 11ft lbs on each bolt. And again, on a dead cold engine to prevent stripping the threads in the aluminum parts. Also to note, not a bad idea to use a touch of Blue loctite on the cover bolts.
When you install the T stat (installs in the cover, then the cover with T stat is bolted to the front of the pump), make sure to have the brass button piece in the flange channel set top dead center up of the Pump housing before reinstalling hose attachment cover plate. The tab on the T stat rubber outer gasket should have it set correctly when the tab is mated to the corresponding channel on the pump, but if not, you may need to spin the rubber gasket on the T stat to potion the tab correctly, and index the T stat flange vent TDC.
And again, 11ft lb total torque on the T stat water cover bolts, so start off with hand tight on the bolts to make sure that you have the T stat with outer rubber ring seated correctly in the pump face recess channel for it, torque to say 5ft lbs on each bolt, then final torque to 11ft lbs on each bolt. And again, on a dead cold engine to prevent stripping the threads in the aluminum parts. Also to note, not a bad idea to use a touch of Blue loctite on the cover bolts.
Last edited by Dano523; Feb 11, 2014 at 07:48 PM.
Le Mans Master
Joined: Jan 2008
Posts: 6,457
Likes: 297
From: corpus christi Texas
Dano553:In the past on some older cars that I've had,I would drain the Rad & maybe pull the lower hose then start the engine and let it run for awhile,watching the temp gage & that would get more of the coolant out.Would that work on the vette?..Thanks..
Last edited by Cherokee Nation; Feb 12, 2014 at 06:12 PM. Reason: add
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
Even with just running a 160* T stat and the system fully charged, you chance shocking the piston sleeves with cold water when the T stat first opens; end up damaging the sleeves and pistons from the metal contracting since the tolerances are so tight on motor.
Furthermore, not sure if anyone brought you up to speed on the aluminum LS motors, but until the engine oil gets up the temp as well (say 170* of better on the gauge), you should not be hard rev'g the motor for the same reason.
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Le Mans Master
Joined: Jan 2008
Posts: 6,457
Likes: 297
From: corpus christi Texas
On a aluminum engine, not no, But HELL NO!!!!!!!!
Even with just running a 160* T stat and the system fully charged, you chance shocking the piston sleeves with cold water when the T stat first opens; end up damaging the sleeves and pistons from the metal contracting since the tolerances are so tight on motor.
Furthermore, not sure if anyone brought you up to speed on the aluminum LS motors, but until the engine oil gets up the temp as well (say 170* of better on the gauge), you should not be hard rev'g the motor for the same reason.
Even with just running a 160* T stat and the system fully charged, you chance shocking the piston sleeves with cold water when the T stat first opens; end up damaging the sleeves and pistons from the metal contracting since the tolerances are so tight on motor.
Furthermore, not sure if anyone brought you up to speed on the aluminum LS motors, but until the engine oil gets up the temp as well (say 170* of better on the gauge), you should not be hard rev'g the motor for the same reason.