Burping A Cooling System

[c3po]

This is a small block chevy engine, the car is a 1983 Chevrolet El Camino, so there are NO BLEED SCREWS.

I had recently put in a Stant 195 thermostat, I did not put any coolant in because I wanted the thermostat gasket to dry. I had drilled a tiny hole in the thermostat since I do not have a heater core and I have pipe plugs in the water pump and intake manifold where the hoses go. I had left the radiator cap off as well as the lower hose, and I left the upper hose off, so a lot of air must have been trapped.

I added the coolant but forgot to bleed the cooling system, the coolant gauge was fluctuating so the next day I took the radiator cap off and started the car and I waited for the coolant to heat up and bubble into the radiator, temp was more consistent.

I took the thermostat out yesterday and put in a Robertshaw high flow thermostat since I have an Edelbrock high flow water pump, my feeling was that the Stant thermostat was running a little to hot because it could not keep up with the flow.

Hopefully this will lead to less air in the cooling system, after I drained the radiator, I attached the lower hose, and I took off the radiator cap. I poured the coolant into the intake manifold ( thermostat housing area) and it filled up the radiator halfway, I stopped pouring before the coolant reached the top of the thermostat housing.

I then put in the thermostat, and tightened down the housing and put the hose on, I put the radiator cap back on.

Of course I drilled a small hole in the thermostat just in case there are any air bubbles. Again the radiator is halfway full, I will be starting the car later today or tommorow.

So, How do I bleed this cooling system properly, correct me if I am wrong.

1) Take radiator cap off
2) Start car
3) run it until coolant gets hot
4) wait for it to bubble
5) Put radiator cap on

Any advice would be appreciated.

 

[jldcol]

That should work, if the radiator neck is the highest thing in the system. May need to raise from of car, any ramps handy?

 

[c3po]

Originally Posted By: jldcol
That should work, if the radiator neck is the highest thing in the system. May need to raise from of car, any ramps handy?


The radiator neck is the highest point in the system on my car, but I will check to make 100% sure that it is the highest point.

I do have pipe plugs in my intake manifold, so I will have to see if these are higher or lower, but I do have ramps.

 

[Kestas]

I don't fuss much. When refilling the cooling system, I fill up, then run the engine until it sucks in the fluid (sometimes quickly), then top off until it looks like it won't take more. That makes it good for starters.

I try not to waste gas, so I just top off the coolant every morning until it takes no more (usually just one iteration). I imagine proper bleeding is more for shops who work on cars for a living and don't have the luxury of multiple mornings.

 

[Drew99GT]

I try and run the engine with the cap off until the thermostat opens, but lately that has led to the coolant expanding and spilling out all over everything while I'm inside getting a beer. So I just run it with the cap off until it's about to overflow, then I stick the cap on. Always do the obligatory morning checks for a few days after working on the cooling system.

 

[c3po]

I noticed with the other thermostat that also had the whole drilled into it, that I could hear gurgling from the thermostat housing area, I will see how it goes with this different thermostat.

It is higher flowing and I did drill a larger hole, about 1/8th or so, the other thermostat that I drilled the hole in was even smaller, I will let everyone know what happens.

The gurgling sound was when the car was shut off, maybe I should have listened when the engine was running, oh well.

 

[demarpaint]

Fill the radator to the weep hole, fill the overflow tank to between the cold and hot mark drive the car till the T-Stat opens. When the car is cool check both levels, add and repeat, it takes a few times, the system will bleed out.

 

[c3po]

The strange thing is that the coolant level was always where it needed to be in the radiator and the overflow tank.

 

[jldcol]

I think that is why you burp, the air bubble traps fluid so it can't flow and levels won't change.