# Air in cooling system **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [November 14, 2007, 2:34am UTC](https://community.cartalk.com/t/air-in-cooling-system/7251 "2007-11-14T02:34:01Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![2000JIMMY](https://avatars.discourse-cdn.com/v4/letter/2/3e96dc/32.png) [@2000JIMMY](https://community.cartalk.com/u/2000JIMMY)\ **Post date:** [November 14, 2007, 2:34am UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/1 "2007-11-14T02:34:01Z")
I just installed a new thermostat in my 97 Chevy S-10 Blazer with a 4.3. How do I get the air out of the cooling system? I filled the radiator at the radiator cap and made sure the overflow jug was full, ran vehicle until hot, checked fluid at the radiator cap, still full and still fluid in jug. Did same again. Still full at radiator. I keep getting a gurgling sound from the heater. Engine gage says engine is operating just fine and heater works great, just that noise. Any help would be appreciated. Thanks. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 14, 2007, 2:53am UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/2 "2007-11-14T02:53:33Z")
Get the engine up to operating temperature. And while the engine is idling, loosen the upper radiator hose clamp slightly at the radiator neck. Slip a thin flat blade screwdriver between the hose and the neck until all the air is purged from the cooling system. Tester ---
**Author:** ![pleasedodgevan](https://avatars.discourse-cdn.com/v4/letter/p/51bf81/32.png) [@pleasedodgevan](https://community.cartalk.com/u/pleasedodgevan)\ **Post date:** [November 14, 2007, 5:36am UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/3 "2007-11-14T05:36:22Z")
Sometimes you can run the engine while parked on a steep uphill. It doesn’t always work but sometimes it does. ---
**Author:** ![edb1961](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/edb1961/32/122_2.png) [@edb1961](https://community.cartalk.com/u/edb1961)\ **Post date:** [November 14, 2007, 1:28pm UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/4 "2007-11-14T13:28:52Z")
I use ramps when I change the coolant in my 2000 Blazer. I back up the Blazer onto the ramps to raise the rear to help drain the fluid. I drive onto the ramps to raise the front end when I add coolant. I run the engine with the radiator cap off to let the air escape. I monitor the coolant level while the engine is running and add coolant as needed. Ed B. ---
**Author:** ![2000JIMMY](https://avatars.discourse-cdn.com/v4/letter/2/3e96dc/32.png) [@2000JIMMY](https://community.cartalk.com/u/2000JIMMY)\ **Post date:** [November 15, 2007, 1:15am UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/5 "2007-11-15T01:15:02Z")
I TRIED THE UPPER RADIATOR HOSE AND SCREWDRIVER. LET IT RUN UNTIL UP TO TEMPERATURE, RELEASED THE CLAMP, INSERTED SEREWDRIVER UNTIL COOLANT CAME OUT WITHOUT AIR. STILL SAME. WILL TRY OTHER “TRICKS”. THANKS ---
**Author:** ![2000JIMMY](https://avatars.discourse-cdn.com/v4/letter/2/3e96dc/32.png) [@2000JIMMY](https://community.cartalk.com/u/2000JIMMY)\ **Post date:** [November 15, 2007, 10:38pm UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/6 "2007-11-15T22:38:07Z")
Well i tried the hill, that didn’t work either. So, I cut the heater hose and installed a flush port. I then got the vehicle up to temperature, opened the cap with engine running and left it open until I got a good bit of coolant out. I then recapped the port and let it set overnight. I drove it about 50 miles today and so far, it seems to be OK. ---
**Author:** ![Craig58](https://avatars.discourse-cdn.com/v4/letter/c/3da27b/32.png) [@Craig58](https://community.cartalk.com/u/Craig58)\ **Post date:** [November 15, 2007, 10:42pm UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/7 "2007-11-15T22:42:15Z")
That sounds like it should work. I don’t know the layout of your system, but when I drain/flush/fill my coolant system I usually disconnect the heater hose and directly fill the core with the hose held higher than the core. I also make sure the heater control valve is in the open position. That seems to work. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 15, 2007, 11:34pm UTC](https://community.cartalk.com/t/air-in-cooling-system/7251/8 "2007-11-15T23:34:57Z")
You could also install a purge valve in the upper heater hose…if your vehicle doesn’t already have one.