Burping the cooling system
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Burping the cooling system
Ok, I've seen this topic come up about 3 times in the past couple of months but I'll be darned if I can find any of the topics anywhere, and of course I didn't write them down. So, How do you do it? Thanks guys.
Race Director
Joined: Jun 2001
Posts: 10,956
Likes: 680
From: Marlboro country MA
Re: Burping the cooling system (mn_vette)
You throw a towel over your shoulder. Then you pick up the car and hold it on top of the towel. Gently patting its backside, allow that baby to burp. :D :D :D
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Burping the cooling system (mn_vette)
Starting with a cold engine, loosen rad cap to the last stop where you have to push down to further loosen. Start engine and when it gets to the thermostat opening temp, race engine by pulling on the throttle link and remove the rad cap all the way. If you had air in the cooling system the coolant level will be below the filler, and so you just fill it up, put the cap back on , and then release the throttle link to normal idle. You may have to do this more than once to get all the air out. If you do this with the car parked on an incline, nose up, you have a better chance of getting all the air out the first time. Never, never ,never open the radiator cap with a hot engine because it will explosively boil out of the filler and scald you, and may blind you. Start cold.
Racer
Joined: Jul 2000
Posts: 421
Likes: 0
From: Glen Burnie Md
Re: Burping the cooling system (mn_vette)
MN Vette,
This comes to you directly out of TPiS' Insider Hints:
When you fill the radiator on a Corvette, you need to do what the local Corvette mechanic calls 'packing'.
With the radiator as full as you can get it, and the motor 'off', put on the radiator cap.
Start the motor, and let it warm up a little (to about 100*).
Before you carefully remove the radiator cap, squeeze the top radiator hose.
If you feel pressure, shut off the motor, and let it cool. Do not take off the cap, if you feel pressure in the hose.
When the motor is warm, and there's no pressure in the radiator hose, remove the cap slowly, using a rag to protect your hands. With the cap safely off, and the motor running, reach over to the throttle and raise the RPM to about 2500 RPM.
Hold the engine speed there while you add coolant until the radiator is completely full. Put the cap back on while the motor is still at 2500 RPM.
This purges all the air from the block and the radiator is now full. Any excess will be vented to the catch tank.
Hope this helps.
This comes to you directly out of TPiS' Insider Hints:
When you fill the radiator on a Corvette, you need to do what the local Corvette mechanic calls 'packing'.
With the radiator as full as you can get it, and the motor 'off', put on the radiator cap.
Start the motor, and let it warm up a little (to about 100*).
Before you carefully remove the radiator cap, squeeze the top radiator hose.
If you feel pressure, shut off the motor, and let it cool. Do not take off the cap, if you feel pressure in the hose.
When the motor is warm, and there's no pressure in the radiator hose, remove the cap slowly, using a rag to protect your hands. With the cap safely off, and the motor running, reach over to the throttle and raise the RPM to about 2500 RPM.
Hold the engine speed there while you add coolant until the radiator is completely full. Put the cap back on while the motor is still at 2500 RPM.
This purges all the air from the block and the radiator is now full. Any excess will be vented to the catch tank.
Hope this helps.
Racer
Joined: Aug 2001
Posts: 272
Likes: 0
From: Somewhere in GA
Re: Burping the cooling system (mn_vette)
In addition to that there are two brass screws that will evacuate some of the the air pockets. One is located near the thermostat from the left side of the motor and one near the throttle body from the right. I performed the "burp" routine and still found that there were air pockets in these areas. If you're changing fluid or refilling a very low system these areas might be beneficial to check out too. At least I know they are there on my 94.........
:seeya
[Modified by Dragon2U, 7:50 AM 3/12/2002]
:seeya
[Modified by Dragon2U, 7:50 AM 3/12/2002]
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Burping the cooling system (Dragon2U)
For my car, I removed the driver's side upper radiator hose, then filled the system until coolant started coming out of the vent plug on top of the thermostat. Another way is to remove the small vent hose at the top of the radiator passenger's side instead of the large hose on the driver's side.
Advanced
Joined: May 2001
Posts: 68
Likes: 0
From: Leominster MA
Re: Burping the cooling system (mn_vette)
Pardon my ignorance, but what do you gain by burping, aside from making sure you have all the coolant the car will hold? Does some air in the system make all that much difference?
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Racer
Joined: Jul 2000
Posts: 421
Likes: 0
From: Glen Burnie Md
Re: Burping the cooling system (Spike T)
Spike,
I am a perfect example of why this 'burping' should be done.
I changed a thermostat...filled my radiator,...and took my Vette out for a run.
First thing I noticed, was the fact that I was'nt getting a 'steady' reading, as far as coolant temperature was concerned. Went from 180* to 210* continuously...up and down...this after replacing a 2 year old 160* tstat.
Little did I know at the time, I had created 'air pockets' when I changed the thermostat.
I took it to a mechanic who did exactly what TPiS' Insider Hints suggests...concerning 'packing'...or in this case 'burping'...described earlier in a previous reply to this posting.
No problems since. Runs 180* or below. I'm happy!!
I am a perfect example of why this 'burping' should be done.
I changed a thermostat...filled my radiator,...and took my Vette out for a run.
First thing I noticed, was the fact that I was'nt getting a 'steady' reading, as far as coolant temperature was concerned. Went from 180* to 210* continuously...up and down...this after replacing a 2 year old 160* tstat.
Little did I know at the time, I had created 'air pockets' when I changed the thermostat.
I took it to a mechanic who did exactly what TPiS' Insider Hints suggests...concerning 'packing'...or in this case 'burping'...described earlier in a previous reply to this posting.
No problems since. Runs 180* or below. I'm happy!!
Advanced
Joined: May 2001
Posts: 68
Likes: 0
From: Leominster MA
Re: Burping the cooling system (UDLUV12)
This sounds like "vapor lock", a condition I used to have to deal with as a boilerman in the Navy. When a water moving system gets hot, any significant amount of air in the system heats up, essentially blocking the movement of liquid, and the whole thing goes nutty, overheats and defeats its own purpose. That would be why it could kill an engine. In the ship's firerooms we used to break out a firehose and hose down the vapor locked water pump with cold sea water to break the lock, but I guess that's not practical in a C4 Vette. Burping sounds like a better approach.
Thanks for the info! :cheers:
Thanks for the info! :cheers:
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Burping the cooling system (mn_vette)
The funny thing about the vette, the 92 at least is how the coolant is routed. Somehow it is routed such that enough coolant can bypass the thermostat, you can do some cool things.
The best of which comes if you have an electric water pump, you can flush, burp, purge, fill, whatever, your coolant system while the motor is cold. Turn on the water pump and start filling it with water. Open the bleed screws every few minutes to make sure there is no air in that part of it. When the coolant return is a solid stream with no air bubbles, and the bleed screws let out a solid stream, and it won't take any more water, you're full. All of this is done without getting burned.
I'm not sure what it is about the coolant routing on the vette, the same trick doesn't seem to work on a camaro.
The best of which comes if you have an electric water pump, you can flush, burp, purge, fill, whatever, your coolant system while the motor is cold. Turn on the water pump and start filling it with water. Open the bleed screws every few minutes to make sure there is no air in that part of it. When the coolant return is a solid stream with no air bubbles, and the bleed screws let out a solid stream, and it won't take any more water, you're full. All of this is done without getting burned.
I'm not sure what it is about the coolant routing on the vette, the same trick doesn't seem to work on a camaro.
