Knocking sound...?

[Jim Lepage]

I've tested it tonight and there's no bubbles in the system but when I was r3ving it with the thermosthat open, I've noticed that the coolant was going up and down a little bit, so I think something in the system is blocking it.

Could it be something in my heater core or maybe the heater valve because it's knocking quite a lot in this area ?

Next step is to bypass the heating system...

[Jean]

Does it make the noise when the fan is OFF?

[Jim Lepage]

Does it make the noise when the fan is OFF?

Yup.

[Jean]

I would bypass the heater core next as it's the next easiest thing to do... if the noise goes away, you know where to look.