Rad cap pressure

[lynnx22]

Re: Rad cap pressure

Hi Andy,
I would say that there are only 2 reasons for losing water out the cap.
1) The cap leaks (for a variety of reasons)
2) The system is over pressuring (also for a variety of far more EXPENSIVE reasons)
Given that the cap is ancient, looks past it and only costs pennies, thats what I,d change first, and for a standard pressure cap.
One solution at a time, or you never know which one cured it.
Good Luck !
Tim

[philcoyle]

Re: Rad cap pressure

As a precaution measure the rad neck inside, from top to where the cap seal sits, not all rads and caps are compatible. Shallow depth of neck and greater length of rad cap should seal .
Basically measure the cap under the top to the seal and measure the depth of the rad neck, cap length must be greater than neck depth to seat properly.

If all checks out okay, but you are still pushing out water, then I am sorry to say you may be experiencing head gasket failure.

[andyf]

Re: Rad cap pressure

So, what looked like water being pushed out past the radio cap is actually a leak from the top hose where it joins the rad :-(

[stevejgreen]

Re: Rad cap pressure

Was it a higher pressure rad cap that caused the issue to become more observable, or just chance?

[andyf]

Re: Rad cap pressure

The rad cap is the same pressure, I have a nasty feeling that tightening up the hose just cracked it some more at the joint. The hose is not as tight as I'd like on the rad end so I wrapped some tape round it to make it a tighter fit. Now either that's just made the problem worse or it's just that the joint to the rad has cracked, either way it's leaking more than ever now, I've actually got visible drips today

[andyf]

Re: Rad cap pressure

I've cleaned up the join from the pipe to the header tank and I can't see any sign of cracking so I think it must be the sloppy hose fit...

[andyf]

Re: Rad cap pressure

I cleaned up the inlet to the header tank and used some evostic steel reinforced epoxy stuff to strengthen the join between the inlet and the header tank and re-fit the hose. A quick test and it still leaks

The thermostat outlet and the radiator inlet are both 32mm OD and the pipe I have is 32mm ID... the question is is that right or should I go for some 30mm ID pipe?