[pavulis97]

Completely normal.
Coolant expands with heat and creates the system pressure and increases the boiling point.
Releasing that pressure with a hot engine will produce localised boiling at the hottest parts of the system, so not a good idea to open when the engine is hot.

The max pressure should be marked on the coolant cap.

Thank you!
What do you think about bubbles?

 

[pavulis97]

What you wrote here seems pretty normal to me .

Do you have some coolant-cooling-heating issues?

If not, nothing to worry about. What you wrote is completely normal behaviour.

Experienced a overnight coolant leaks from one of the coolant system hoses, tightened it and now seems like the leak is gone. Im asking about a pressure because another alfa 147 1.9 jtd 8v (mine is 1.9 jtd 16v) has almost no pressure in cooling system and no bubbles in expansion tank with cap detached and engine running.
I also experience starting issues and blueish smoke described in this section 1.9 JTD Poor hot start / Oil Smoke

Thank You!

 

[pavulis97]

Thank you for your kind answers, will try a compression test and a sniff test!

 

[pavulis97]

Thanks guys! Right now my car sits in the garage for winter time, still waiting for a sniff test to arive, will try a sniff test and post the results.

 

[pavulis97]

Tried sniff test, fluid did not change its colour, but i definitely see air going through this fluid, strange