Bleeding coolant system

[warrick]

just had the coolant changed in my 6.0 calais and ever since the top radiator hose is collapsing when the motor cools down to cold. fully pressurised when hot though. is this normal ? do these motors have a bleed nipple or are they self levelling?
thanks for any help
cheers
warrick

 

[ChRiDDa]

Time to replace your radiator cap

 

[warrick]

thanks for the reply. if the radiator cap was faulty wouldnt the system not hold pressure when it was hot?

 

[scaredyet]

Change the cap

 

[ChRiDDa]

thanks for the reply. if the radiator cap was faulty wouldnt the system not hold pressure when it was hot?

The rubber seal on the cap will be knackered - it will cause issues when the system heats up and cools down again ie allowing excess coolant to flow to the overflow bottle when at operating temp and drawing it back from the overflow when it cools down again

The giveaway sign is the top hose not retaining its shape - I believe new caps are around $20 for a genuine item

 

[warrick]

cool thanks for that.will get one tomorrow. strange that it went when the coolant was changed.must have been just hanging in there and being undone and on a couple of times was enough to finish it off.
cheers
warrick

 

[LodiBruce]

Radiator caps are two-way devices. They hold pressure via a spring. You get the pressure when the closed cooling system is heated. No place for the expanding fluid to go. UNTIL the pressure exceeds the capacity of the spring. Then the fluid escapes into your reservoir tank. BUT, when that same closed system cools down, it is NOW under a vacuum. This is where your cap is failing. Because, there is a valve in the cap that is supposed to open under vacuum allowing the excess fluid in your reservoir tank to be pulled BACK INTO your cooling system. Thus keeping it topped off all the time. B.

 

[warrick]

thanks for everyones info. will get the cap and all should be good
cheers

 

[warrick]

replaced cap and all good again guys. thanks for the help. must admit it is the first cap i have had to replace in the last 5 cars i have owned. 5 years doesnt seem very long to need replacing, only done 58k.
thanks again
cheers
warrick

 

[Anthony121]

My V6 calias had the same problem in less than 3 years. Just a part failure.