cooling problems
04-12-2011, 10:08 PM
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cooling problems I am having issues with coolant boiling in my 98 Z28, I put in a new radiator last November as the side tank developed a crack in the original radiator, it boiled over right away pushing coolant out of the resv. tank but I thought that I might have over filled it, everything seemed to be working fine until the weather here in the south warmed up, and it is boiling over when the temp gauge reaches the 220 mark, I have replaced everything except the water pump and the heater core, I can see water flow through the filler neck and it is blowing hot air, fans are also kicking in, my concern is the replacement has the bungs and the internals for the automatic transmission and mine is a manual, oreilly auto has only one part number for the part and it is universal for both automatic and manual transmission any help would be appreciated
04-13-2011, 09:16 PM
#4
to bleed air unhook the little coolant hose at the throttle body. this is the highest point in the cooling system.
with engine off and cold, remove radiator cap and slowly fill the radiator with coolant and keep filling radiator till coolant comes steadily out the throttle body hose. You will make a slight mess and have a few ounces of coolant on the motor, hose it off when finished. It's a slow process and should take 5-10 minutes once coolant is at the top of the radiator neck. Reconnect throttle body hose, top off radiator and install radiator cap. You will have minimal air in the system at this point that should pose no problem and will work itself out under normal warm up cool down cycles.
If you do this and don't have the plastic coolant recovery tank connected, you initially won't have an overheat problem but the cooling system will push out coolant once it heats up to normal operating temp. If the coolant recovery tank is not connected and functioning, when the system cools it will want to draw coolant back in and if it doesn't get coolant from the recovery tank it will pull air into the system, so you need a coolant recovery tank.
cause of coolant boiling is
a) air in the system resulting in system not building up pressure
b) bad radiator cap which results in system not holding pressure resulting in (a)
c) coolant boils under normal operating temp because of (a) and (b)
d) less than a 50/50 mix of antifreeze and water which results in (c), this easily happens when you flush the cooling system with water then fill with a 50/50 mix and you have a significant amount of water left in the block. check your coolant mix ratio and verify system holds pressure. 50/50 coolant should not boil till 265 F under 15psi.
with engine off and cold, remove radiator cap and slowly fill the radiator with coolant and keep filling radiator till coolant comes steadily out the throttle body hose. You will make a slight mess and have a few ounces of coolant on the motor, hose it off when finished. It's a slow process and should take 5-10 minutes once coolant is at the top of the radiator neck. Reconnect throttle body hose, top off radiator and install radiator cap. You will have minimal air in the system at this point that should pose no problem and will work itself out under normal warm up cool down cycles.
If you do this and don't have the plastic coolant recovery tank connected, you initially won't have an overheat problem but the cooling system will push out coolant once it heats up to normal operating temp. If the coolant recovery tank is not connected and functioning, when the system cools it will want to draw coolant back in and if it doesn't get coolant from the recovery tank it will pull air into the system, so you need a coolant recovery tank.
cause of coolant boiling is
a) air in the system resulting in system not building up pressure
b) bad radiator cap which results in system not holding pressure resulting in (a)
c) coolant boils under normal operating temp because of (a) and (b)
d) less than a 50/50 mix of antifreeze and water which results in (c), this easily happens when you flush the cooling system with water then fill with a 50/50 mix and you have a significant amount of water left in the block. check your coolant mix ratio and verify system holds pressure. 50/50 coolant should not boil till 265 F under 15psi.
04-14-2011, 08:56 PM
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coolant was the issue, i cut corners when i installed the new radiator and used one pre mixed jug of coolant, when it started to boil off i refilied with strait water, once i put in 2 gallons of properly mixed dexcool, and ensured that the air was out of the system everything is fine, cutting corners cost me a $100 tow and a day of vacation
