Need to burp system ???
Thread Starter
Instructor
Joined: May 2012
Posts: 122
Likes: 0
From: Waxhaw NC
Need to burp system ???
I just cleaned my throttle body on my '93 and obviously during the process air was introduce in the system when the coolant hoses were pulled off.
Do I need to burp the system or does it burp by itself? If so, how do I burp it? Thank you.
Do I need to burp the system or does it burp by itself? If so, how do I burp it? Thank you.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
There should be a screw on top of the water neck. Locate this screw and determine if you need a screwdriver or wrench to open it. Get your needed tool. Place a shop rag under the water neck. be sure that the rag is clear of the belt and pulleys with lots of room for clearance. Start the car and let it run. Turn the screw or use the wrench to turn the bolt slowly. You should see bubbles come out along with the trapped air. When coolant starts to come out, tighten it back up. Let the car run a couple of minutes longer and do the same thing again.
Do this 3-4 times and you should have removed most or all of the air from the system. The rag is under the water neck to catch the coolant so it does not get on the OPTI.
Do this 3-4 times and you should have removed most or all of the air from the system. The rag is under the water neck to catch the coolant so it does not get on the OPTI.
Thread Starter
Instructor
Joined: May 2012
Posts: 122
Likes: 0
From: Waxhaw NC
There should be a screw on top of the water neck. Locate this screw and determine if you need a screwdriver or wrench to open it. Get your needed tool. Place a shop rag under the water neck. be sure that the rag is clear of the belt and pulleys with lots of room for clearance. Start the car and let it run. Turn the screw or use the wrench to turn the bolt slowly. You should see bubbles come out along with the trapped air. When coolant starts to come out, tighten it back up. Let the car run a couple of minutes longer and do the same thing again.
Do this 3-4 times and you should have removed most or all of the air from the system. The rag is under the water neck to catch the coolant so it does not get on the OPTI.
Do this 3-4 times and you should have removed most or all of the air from the system. The rag is under the water neck to catch the coolant so it does not get on the OPTI.
Now do I need to get the car warmed up before I can do this procedure or can I start right away as soon as I get the car running?
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
You should open the bleed valve(s) then add coolant to the surge tank. If you have the engine running, you may see coolant coming out of the bleed valves because the W/P is working.
My old 92 had a bleed valve on the TB, too. It was next to the throttle body hose on the driver's side of the TB. Open both of the valves then add coolant. Once you see coolant coming out of the valves, close them and then finish filling the surge tank.
Start the engine and let it run until the thermostat opens. You will see a drop in the coolant level when that happens. Raise engine RPM to something like 1000-1200RPM and fill the tank to the bottom of the filler neck, then replace the cap. Shut the engine off and let the coolant temp drop to about 100 degrees. Remove cap and check the level. Re-start the engine, raise the RPM and add coolant as necessary.
The FSM specifies to do this 3 times if doing a flush and refill. It also says to not do any WOT stuff until the engine has gone thru 3 cycles of going to operating temp and cool down to 100 degrees or less.
My old 92 had a bleed valve on the TB, too. It was next to the throttle body hose on the driver's side of the TB. Open both of the valves then add coolant. Once you see coolant coming out of the valves, close them and then finish filling the surge tank.
Start the engine and let it run until the thermostat opens. You will see a drop in the coolant level when that happens. Raise engine RPM to something like 1000-1200RPM and fill the tank to the bottom of the filler neck, then replace the cap. Shut the engine off and let the coolant temp drop to about 100 degrees. Remove cap and check the level. Re-start the engine, raise the RPM and add coolant as necessary.
The FSM specifies to do this 3 times if doing a flush and refill. It also says to not do any WOT stuff until the engine has gone thru 3 cycles of going to operating temp and cool down to 100 degrees or less.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
The LT1 in your '93 is self-bleeding. Just fill the expansion tank to the brim, and the overflow tank to the 'cold' level. Run the engine at idle, or go for a drive to bring the temp to op level (190-210). After cool-down, add coolant, if necessary. Done.
PS... yes, I'm aware of the bleed screws, and have read all the horror stories about the gigantic bubbles in the system. If you are apprehensive
about not bleeding your vette, go right ahead and open the bleed valves.... it's your vette.
PS... yes, I'm aware of the bleed screws, and have read all the horror stories about the gigantic bubbles in the system. If you are apprehensive
about not bleeding your vette, go right ahead and open the bleed valves.... it's your vette.
Last edited by don hall; Jan 4, 2015 at 06:27 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
Due to the expansion tank being above the bleed fitting on the thermostat housing and on some models that is ONE on the throttle body also on the front drivers side...down low on it.
I bleed BOTH. AND I do this without the engine running. As stated in the FSM. NOW...sometimes I have to crank the engine when I am adding coolant in the expansion tank and it does not go down and the coolant does not flow out of the bleed fitting(s).. So I close off the bleed fitting and run the engine for about 30 seconds....then shut off the engine and open the bleed fitting again and keep adding coolant until a SOLID stream of coolant comes out.....when this is achieved...I close off the bleed fitting(s) and your done. Then add more coolant to the tank and that is it.
This coolant system is reverse flow....so bleeding off the air at the thermostat housing is important. I choose to follow the book and not take a chance with a customers car.
Then...when I crank the engine with the radiator cap off....I either look or put my finger in the expansion tank and VERIFY that the hose coming from the TOP of the radiator is flowing coolant INTO the expansion tank. This hose that connects to the expansion tank, top radiator fitting port and also goes to the rear passenger side of the engine can get plugged up.....so I often times remove the ends and blow it them out to make sure that the hose is not plugged up.
DUB
I bleed BOTH. AND I do this without the engine running. As stated in the FSM. NOW...sometimes I have to crank the engine when I am adding coolant in the expansion tank and it does not go down and the coolant does not flow out of the bleed fitting(s).. So I close off the bleed fitting and run the engine for about 30 seconds....then shut off the engine and open the bleed fitting again and keep adding coolant until a SOLID stream of coolant comes out.....when this is achieved...I close off the bleed fitting(s) and your done. Then add more coolant to the tank and that is it.
This coolant system is reverse flow....so bleeding off the air at the thermostat housing is important. I choose to follow the book and not take a chance with a customers car.
Then...when I crank the engine with the radiator cap off....I either look or put my finger in the expansion tank and VERIFY that the hose coming from the TOP of the radiator is flowing coolant INTO the expansion tank. This hose that connects to the expansion tank, top radiator fitting port and also goes to the rear passenger side of the engine can get plugged up.....so I often times remove the ends and blow it them out to make sure that the hose is not plugged up.
DUB
