Purging the Cooling System Guide

[MountaineerTom]

Guide posted here for people to have access to until they get posted in the appropriate section here at GM-TC.

 

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Purging the Cooling System

 

If you have a gurgling sound coming from what sounds like inside the dashboard, you probably have and air pocket in your cooling system. It’s an easy fix, here’s what you need to do.

 

1) Get a jug of DEXCOOL (Havoline brand is GM approved).

2) Park on level ground.

3) The engine needs to be cool, or just slightly warm is fine too.

4) Add fluid in the surge tank until the level is slightly above the split line on the tank (an inch or so).

5) Put cap back on loosely, don't allow it to build pressure.

6) Start engine and let it idle for a minute.

7) Cycle the engine from idle to 3000rpm in 30-second intervals until the engine coolant reaches operating temp and the thermostat opens.

8) Shut off engine and remove the cap.

9) Start engine and let it idle for a minute. Fill the tank to 1/2 inch above the "Cold Full" mark on the tank & put cap back on loosely.

10) Cycle the engine like before and wait for the thermostat to open again, then shut off the engine.

11) Put more fluid in if necessary, the fluid should be a half-inch or so above the Cold Full mark.

[k1500chevy97]

Gonna have to give that a try . Thanx Tom

[99silveradoz71]

Definitely a current issue I hope to adress in a few weeks when a buddy comes up from KY to do some work on our Rados.

[chevroletmb]

back flushing the heater core car help with the noise as well

some vehicles have a fluid restrictor at the heater core that can make this type of noise as well.

just some tips if flushing doesn't help

[JayMan]

I used to have a gurgling sound from the heater core when I kept the coolant at the recommended level.

 

I forget if I read the post here or at another site, but folks were really upset about Dex-Cool, which they called "Death-cool." I guess a few folks that never checked their cooling systems, ran the coolant 6 inches low, suddenly had problems with corrosion and head gasket failures!

 

This summer, with only 50,000 km / 30,000 mi on the truck, I took it to the dealer to have it flushed, new thermostat, etc. The service dude thought I was nuts but happily took my money

 

I like how you have to change the entire thermo housing just to change the thermo! Good money-maker there!

 

They let me observe while they flushed and checked everything. The flush came out clean, and several rinses came out clean. Oh well. The mechanics thought it was all good, clean fun.

 

The service dude then suggested that I fill the surge tank to the top, as they did. The excess will go out the overflow anyway, and the coolant level will stabalize about 2 inches below the filler neck. No more gurgle.

[02denali]

i have found another way to do this.if you have done the tbbypass or not. if you drain the coolant.

remove the line from the throttle body--no bypass--on the inlet side of throttle body and block off the yhe fitting with something--finger--and hold it up. begin filling the cooling system until you get some fluid coming out of the hose. then hook it up. may spill a tiny bit.leave the cap off and start her up and run for a few minutes. then install the cap and drive around the block. shut her off and let her sit a few minutes and then remove the cap.this has worked for me several times. good luck.