Technical Bleeding Coolant System

[Sasha1995]

Hello again all,

I need some help. I've just changed the radiator cross support on my B and have therefore changed the coolant.

When it comes to bleeding the system what is the best protocol? I started with the car with expansion tank cap off and did try to run it up to temperature but then the coolant started flowing out the tank (so I stopped the engine). I did also try to loosen the bleed nipple on top of the radiator but no air system to come out (heater was also set to max temperature).

Is there anything I'm missing or a specific protocol I should be following?

Many thanks,

Sasha

 

[Voko]

Hello again all,

I need some help. I've just changed the radiator cross support on my B and have therefore changed the coolant.

When it comes to bleeding the system what is the best protocol? I started with the car with expansion tank cap off and did try to run it up to temperature but then the coolant started flowing out the tank (so I stopped the engine). I did also try to loosen the bleed nipple on top of the radiator but no air system to come out (heater was also set to max temperature).

Is there anything I'm missing or a specific protocol I should be following?

Many thanks,

Sasha

Sound like you are on the right lines. I normally remove the bleed nipple completely, while I fill with coolant, and as soon as liquid starts to appear pop it back in again. Once the engine is running squeezing a few pipes, with the expansion cap off can help clear air…after a run you might need to bleed a bit of air and top up…

 

[Noideadave]

Sound like you are on the right lines. I normally remove the bleed nipple completely, while I fill with coolant, and as soon as liquid starts to appear pop it back in again. Once the engine is running squeezing a few pipes, with the expansion cap off can help clear air…after a run you might need to bleed a bit of air and top up…

I don’t think you need to bleed the system after a refill. There are two bypasses. One is the heater matrix and the other is the throttle body (on some models). These help bleed the system. I emptied mine a couple of times because of a small leak on the oil cooler and it all worked fine after.