DIY Feeding and Burping a cooling system
#1
03-09-2009, 12:09 PM
Join Date: Mar 2009
Location: Western PA
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DIY Feeding and Burping a cooling system
SO, you just installed a new radiator and thermostat in your rig, got all the hoses hooked back up and filled it with 50/50 mix coolant, took it for a ride and 
it's running HOT. You take it back home, remove the rad cap and it's low, dump in another 1/2 gallon or so of coolant and it looks good. Then a few days later it's running a little warm again, so you add some more coolant and it's good.
Want to avoid all that, and only have to fill it once. Read below and find out how to FEED and BURP your cooling system.
When you drain a cooling system you have basically added LOTS and LOTS of air to it. Just like a hydraulic brake system, air in a cooling system is BAD (we'll get into brake system bleeding in a later article). One of the first things is filling it correctly, and getting all the air out when filling it. All cooling systems have a restriction system built in them, it's called a thermostat. When filling the system the stat wolnt allow the coolant past it till it gets hot and opens (the reason it got hot after your first test ride). Now something I've noticed on most newer factory thermostats is a bleeder valve, most replacement stats don't have this but, it's easy to add. All you have to do is drill one or two 1/8" holes in the flange of the stat. These small holes wolnt mess up the way the system cools, just make it easier to fill.
TYPES OF COOLING SYSTEMS
There are basically two types of cooling systems, the so called OPEN and so called CLOSED. The OPEN system is identified as having a pressure/fill cap on the radiator. The closed has the pressure/fill cap located somewhere else in the system, commonly a "anti-aeration bottle", which most people call a pressure bottle and is usually located near the rear of the engine compartment on the firewall. The "CLOSED" style systems are becoming popular due to space constraints in newer cars.
Both systems works pretty much the same with the "OPEN" system using the radiator it's self for anti-aeration. A little about anti-aeration systems. Basically this is the highest point in the system, and any air will eventually find it's way to the highest point.
FILLING THE SYSTEM.
Make sure you are working a fairly level surface.
CLOSED SYSTEM
OK, you got the new rad in, your vented thermostat installed, and the lower hose hooked up and the clamps tightened down. STOP, don't tighten down that upper hose just yet. Put it on the rad and twist it around so the engine end of the hose is pointing UP, now snug the clamp on the rad just a little, and find a funnel that fits in the open end of the upper hose. That's where you're gonna start filling the system from. Remove the cap from the pressure bottle, and start pouring the coolant in. Fill from the rad hose till coolant starts trickling from the thermostat housing (see what that vent did for ya), loosen the clamp on the rad and finish installing the upper hose. Now, get your jack and raise the rear about 6" (this makes sure the pres bottle is the HIGHEST point in the system). Continue filling the system at the bottle till it hits the COLD fill lines on the bottle. Fire it up, run it for 10 min to get the stat to open up, shut it off and top off the coolant, continue doing this till the the bottle stays full. Keep away from the bottle when it's running, if any air burps out it could spray some HOT coolant out of the bottle. Shut it off, put the cap on, lower it off the jack, and take it for a good test run to get it hot. Check the coolant level when you get home, it should be full.
NOTE: If you are working on an incline try to have the rear of the vehicle higher than the front.
OPEN SYSTEM
Well it's just a little different procedure for this system, here you want all the hoses connected and tight. Raise the front about 6" (this makes sure the radiator is the HIGHEST point in the system), and fill through the fill neck. You will hear the coolant gurgling as the air is pushed past the vent holes you drilled in the thermostat. When the rad gets full, wait a few min for the coolant to settle and fill it again. You don't want to fill it FULL, leave about 1/2" below the fill neck for anti-aeration. Start it up with the cap off and run it for 10 min to get the stat to open up, shut it off and top off the coolant, continue doing this till the the rad stays full (1/2" below the fill neck). Keep away from the opening when it's running, if any air burps out it could spray some HOT coolant out. Shut it off, put the cap on the rad, lower it off the jack, and take it for a good test run to get it hot.
NOTE: If you are working on an incline try to have the front of the vehicle higher than the rear.
I have been filling cooling systems this way for years and I usually don't have to go back to top them off them a few days later.
it's running HOT. You take it back home, remove the rad cap and it's low, dump in another 1/2 gallon or so of coolant and it looks good. Then a few days later it's running a little warm again, so you add some more coolant and it's good. Want to avoid all that, and only have to fill it once. Read below and find out how to FEED and BURP your cooling system.
When you drain a cooling system you have basically added LOTS and LOTS of air to it. Just like a hydraulic brake system, air in a cooling system is BAD (we'll get into brake system bleeding in a later article). One of the first things is filling it correctly, and getting all the air out when filling it. All cooling systems have a restriction system built in them, it's called a thermostat. When filling the system the stat wolnt allow the coolant past it till it gets hot and opens (the reason it got hot after your first test ride). Now something I've noticed on most newer factory thermostats is a bleeder valve, most replacement stats don't have this but, it's easy to add. All you have to do is drill one or two 1/8" holes in the flange of the stat. These small holes wolnt mess up the way the system cools, just make it easier to fill.
TYPES OF COOLING SYSTEMS
There are basically two types of cooling systems, the so called OPEN and so called CLOSED. The OPEN system is identified as having a pressure/fill cap on the radiator. The closed has the pressure/fill cap located somewhere else in the system, commonly a "anti-aeration bottle", which most people call a pressure bottle and is usually located near the rear of the engine compartment on the firewall. The "CLOSED" style systems are becoming popular due to space constraints in newer cars.
Both systems works pretty much the same with the "OPEN" system using the radiator it's self for anti-aeration. A little about anti-aeration systems. Basically this is the highest point in the system, and any air will eventually find it's way to the highest point.
FILLING THE SYSTEM.
Make sure you are working a fairly level surface.
CLOSED SYSTEM
OK, you got the new rad in, your vented thermostat installed, and the lower hose hooked up and the clamps tightened down. STOP, don't tighten down that upper hose just yet. Put it on the rad and twist it around so the engine end of the hose is pointing UP, now snug the clamp on the rad just a little, and find a funnel that fits in the open end of the upper hose. That's where you're gonna start filling the system from. Remove the cap from the pressure bottle, and start pouring the coolant in. Fill from the rad hose till coolant starts trickling from the thermostat housing (see what that vent did for ya), loosen the clamp on the rad and finish installing the upper hose. Now, get your jack and raise the rear about 6" (this makes sure the pres bottle is the HIGHEST point in the system). Continue filling the system at the bottle till it hits the COLD fill lines on the bottle. Fire it up, run it for 10 min to get the stat to open up, shut it off and top off the coolant, continue doing this till the the bottle stays full. Keep away from the bottle when it's running, if any air burps out it could spray some HOT coolant out of the bottle. Shut it off, put the cap on, lower it off the jack, and take it for a good test run to get it hot. Check the coolant level when you get home, it should be full.
NOTE: If you are working on an incline try to have the rear of the vehicle higher than the front.
OPEN SYSTEM
Well it's just a little different procedure for this system, here you want all the hoses connected and tight. Raise the front about 6" (this makes sure the radiator is the HIGHEST point in the system), and fill through the fill neck. You will hear the coolant gurgling as the air is pushed past the vent holes you drilled in the thermostat. When the rad gets full, wait a few min for the coolant to settle and fill it again. You don't want to fill it FULL, leave about 1/2" below the fill neck for anti-aeration. Start it up with the cap off and run it for 10 min to get the stat to open up, shut it off and top off the coolant, continue doing this till the the rad stays full (1/2" below the fill neck). Keep away from the opening when it's running, if any air burps out it could spray some HOT coolant out. Shut it off, put the cap on the rad, lower it off the jack, and take it for a good test run to get it hot.
NOTE: If you are working on an incline try to have the front of the vehicle higher than the rear.
I have been filling cooling systems this way for years and I usually don't have to go back to top them off them a few days later.
#3
03-10-2009, 08:43 PM
Join Date: Mar 2009
Location: Western PA
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Just wanted to mention something about the above burping article, if after about 100 miles of driving all the air should be burped out of the system. If you are losing coolant and can't find a leak or still finding air in the system there are other more serious problems than a clogged radiator.
