Dalek cap

[ricicles]

Any one of you clever
People worked a way of testing one of these blighters?

[itchyfeet]

Should quack when you blow down it but if in doubt buy a quality new one.

https://www.brickwerks.co.uk/brickwerks ... -reposted/" onclick="window.open(this.href);return false;

[jrt]

Gives me another chance to show my favourite video again
https://www.youtube.com/watch?v=RT8Ew43mNg4" onclick="window.open(this.href);return false;
David.

[Mr Bean]

Correct me if I am wrong but the quack test, while proving the one way action of the valve, gives no indication of the pressure and thereby the coolant temperature at which it would vent into the overflow tank. Probably only of academic interest unless the coolant is mysteriously boiling over.

[itchyfeet]

Correct me if I am wrong but the quack test, while proving the one way action of the valve, gives no indication of the pressure and thereby the coolant temperature at which it would vent into the overflow tank. .

It's a test
No test is perfect.

Even if you tested the valve the other way you won't have tested it at high temperature or with the correct pressure coolant on one side and air on the other, or tested the plastic has not degraded and about to crack, or that the seal to tank is still OK ....need I go on?

Easier to just buy a quality new one from time to time.

[Aidan]

only way to test one properly is with the proper radiator cap and pressure system test gear which only good garages bother to have nowadays, temp shouldn't come into it really they are a pressure release valve should hold one bar over atmospheric pressure one way and reverse pass under vacuum

[itchyfeet]

temp shouldn't come into it really

Plastic expands a lot when it gets hot and I suggest it could have an affect on the dimensions of the cap which may be critical, only the engineer who designed it will know.

[maxstu]

Gives me another chance to show my favourite video again
https://www.youtube.com/watch?v=RT8Ew43mNg4" onclick="window.open(this.href);return false;
David.

What a colourful chappy. Makes me laugh every time

[ricicles]

Thanks for your replies. Been having trouble since fitting a brand new gen vw one with leaks.
I have replaced most of the hoses and also put in front to rear stainless pipes.
Leaks have poped up all around the system since fitting the cap.
Have odered and fitted a repro one and given it a thrash around so hoping its not going to leak again.
I will check levels in the morning when cool and let you know.

[itchyfeet]

Thanks for your replies. Been having trouble since fitting a brand new gen vw one with leaks.
I have replaced most of the hoses and also put in front to rear stainless pipes.
Leaks have poped up all around the system since fitting the cap.
Have odered and fitted a repro one and given it a thrash around so hoping its not going to leak again.
I will check levels in the morning when cool and let you know.

Maybe it's just working as it should and the old one was not holding pressure, or maybe you used jubilees instead of spring clips, they will tend to leak at first until you tweak them.

[ricicles]

Update!
New cap fitted and no leaks during test run.
As the engine is cooling its started leaking from a new part of the coolant system.
At a total loss now as to how this is happening.
If the pipes were dodgy surely it would leak when under max pressure ie hot and revving.
But it leaks after running when cooling down?

[itchyfeet]

Update!
New cap fitted and no leaks during test run.
As the engine is cooling its started leaking from a new part of the coolant system.
At a total loss now as to how this is happening.
If the pipes were dodgy surely it would leak when under max pressure ie hot and revving.
But it leaks after running when cooling down?

no heat expands parts some materials expand more than others so they may seal hot, cool down parts contract at different rates contract they leak.

You can get leaks hot only due to coolant pressure or cold only due to expansion and contraction.

What pipes exactly and what clips? pics please


You can add pics here and copy BB code link then paste in you post on here
https://www.techpowerup.org/upload" onclick="window.open(this.href);return false;

[itchyfeet]

Also leaks hot can just evaporate so you don't see them

[ricicles]

Ok thanks i get the heat and expansion. The leaks are popping up in different places. On monday at the joint between the brand new stainless front to rear with the new flexi bit in the middle fitted with brand new proper coolant hose clips supplied. Today from the out to the front to rear! If that makes sense? Time before that from the return to the thermostat.
Poor old van

[itchyfeet]

When ever you do a load of work on the cooling system it takes a while to get everything sealed it's common.

Don't despair, they don't call them waterleakers for nothing