Coolant Reservoir Venting

[gsd112]

Hi Guys,

Hopefully someone can help me?

I had a coolant flush last Monday and I supplied a new coolant reservoir and cap (repco). All went well till Thursday when I got to work 50km drive it vented the whole tank on the ground. This is the first time I had run the car without the a/c on since the flush. I let it sit all day and I topped it up to half way between Min cold and Max cold marks. I drove around 25kms with a/c on and stopped and it was just below the hot max mark and stayed there. The rest of the way back to the mechanics I turned off the a/c and when I got to the mechanic it vented again. So the mechanic said it was the cap due to the radiator hose being soft and the system wasn't holding pressure.

So I changed the cap with a genuine one and took it to work today and it did it again with a/c off.

Any ideas what might be causing this? The temperature hasn't changed, its not going over half even if giving it a hard time.

[julesk_1972]

Imho air trapped in the system, me, I fill then squeeze top hose, repeat until takes no more fluid.

Or use a bleed nipple if it exists.

[barnz]

Shouldnt you also do it with the heater on as well?

[gsd112]

All this has been done. I don't know where to go from here. I don't know if I should go back to the original guy and say fix it or just cut my loses and go to a forum sponsor who normally services it but I thought the local guy cant mess a coolant change up. Any idea why its only when the A/C is off?

[gsd112]

I have no pressure in the system. I can take off my reservoir cap after a 30min drive without any issues what is going on?

[Wilko16]

Shouldnt you also do it with the heater on as well?

Coolant is always flowing through the hearter core, the temp control knob/button just controls a little door inside the climate control

Blending hot and cold air to get the set temperature

Old cars had heater taps, anything with climate control has a blending door

[Spookyluke]

I have no pressure in my cooling system at normal running temperature. Once switched off it starts boiling in the top radiator hose and build’s pressure up till boiling stops but don’t lose coolant. Any one know what’s happening?

[k31th]

Thermosiphon, is likely what is occurring with that boiling.

 

you'll definitely have pressure in the system at normal running of the engine, or you'd most certainly have a leak. Have you tried "gradually" loosening the radiator cap (very slowly), while it's running, to see if it has pressure?

 

[Puffwagon]

14 minutes ago, k31th said:

Have you tried "gradually" loosening the radiator cap (very slowly), while it's running, to see if it has pressure?

 

Squeeze the top hose 

[Ivn543]

Has anyone found a solution to this because I'm having the same issue.