The spring and cap are heat/pressure(usually pressure) activated, meaning that as pressure/heat increases the spring in there will coil upwards and open itself slightly for excess water from pressure and allows for that water to come out and into an expansion tank.
There are certain vehicles literally equipped with stronger/stiffer springs in them to handle different amounts of pressure; usually 13psi is the usual but sometimes they are rated upwards of 18psi, each manufacturer is different.
I’m sorry you have ZERO clue how these systems operate, don’t come in here giving bad information especially when it’s a well known item in modern cooling systems since about the 80s and you could have simply googled it if you were unsure.
This nipple is after the spring and cap, the other end of this hose it drains into unpressurised expansion tank that is open to the air. How any pressure can build in it? Doesn’t absence of any clamp on the hose gives any clue?
The last two Hondas I worked on where push on style hoses like this with no clamps because they were low pressure systems.
Both had pressure caps and I was asked specifically which year when at the parts counter because they apparently changed them between model years for the refresh.
The spring and cap are heat/pressure(usually pressure) activated, meaning that as pressure/heat increases the spring in there will coil upwards and open itself slightly for excess water from pressure and allows for that water to come out and into an expansion tank.
There are certain vehicles literally equipped with stronger/stiffer springs in them to handle different amounts of pressure; usually 13psi is the usual but sometimes they are rated upwards of 18psi, each manufacturer is different.
I’m sorry you have ZERO clue how these systems operate, don’t come in here giving bad information especially when it’s a well known item in modern cooling systems since about the 80s and you could have simply googled it if you were unsure.
This nipple is after the spring and cap, the other end of this hose it drains into unpressurised expansion tank that is open to the air. How any pressure can build in it? Doesn’t absence of any clamp on the hose gives any clue?
I’m a mechanic and have been one for 15 years. As someone else said there’s no clamp on the hose. That should give you a clue.
Yes, SOME cars are different, especially newer ones that self burp air out of the system. But 90% of vehicles, do not have pressurized overflow lines.
The springs in radiator caps are there TO allow air and coolant to escape to the overflow tanks when the rest of the system is pressurized.
The last two Hondas I worked on where push on style hoses like this with no clamps because they were low pressure systems.
Both had pressure caps and I was asked specifically which year when at the parts counter because they apparently changed them between model years for the refresh.