Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Varche]

..... How can you tell they have failed? ....

They leak coolant 

Where do they actually leak from?

There's a diaphragm in side it that the vacuum acts on to move the valve. The diaphragm had perished on mine which was where the leak was from.

Sorry if I am being a bit dim but while I can understand the diaphragm perishing, leaking and stopping the hbv from performing as it should surely it is contained within the sealed casing and the only place the coolant can go is elsewhere within the system i.e. down one of the 3 hoses connecetd to the hbv? How is the coolant able to leak out if it is not the casing that is also at fault?  :-?

That is a jolly good question!! I too would like to know? My Dad just asked me has his 5 year old Corsa got the same component? Don't know.

On Saturday I got up and went to my nearest Opel Daler to order a new one anyway. When I got there he was shut, winter hours only Monday to Friday closed 1.30 to 5.30 too. I was less than impressed -40 miles round trip for nada. Still didn't lose any coolant

[Abiton]

Well I've never actually got my hands on one of these to look (my missus's car doesn't have one), but...
There's a wet bit (the coolant passages) and a dry bit (the vacuum diaphragm).  For the dry bit to be able to move a valve in the wet bit, there must be some sort of actuator shaft connected to the vac diaphragm going through some sort of seal into the wet bit, which I would imagine is where it fails/leaks.

[Malcolm_D]

Well I've never actually got my hands on one of these to look (my missus's car doesn't have one), but...
There's a wet bit (the coolant passages) and a dry bit (the vacuum diaphragm).  For the dry bit to be able to move a valve in the wet bit, there must be some sort of actuator shaft connected to the vac diaphragm going through some sort of seal into the wet bit, which I would imagine is where it fails/leaks.

Hmmm... but if it leaking through to the actuator which is operated by a vacuum delvered by the small black pipe to the top wouldn't the coolant just end up going into the vacuum pipe?  :-?

[Abiton]

No 'cos it would be leaking towards the other side of the diaphragm, and there must be a seal round the edges of the diaphragm to keep the vacuum on the 'pull' side. 

The lower side of the diaphragm will have some vents to atmosphere, however, so that it can move, which is where the coolant comes out, I suspect.

[ffcgary1]

It could also be the oil cooler plate leaking mate and then sealing it's self, my dads 3.2 had this symptom and we found the oil cooler was very crusty with coolant deposits all around the plate.  check that before any thing else.

[Richard A]

Sorry 'ENTWOOD' (pretentios prig) maybe the expression 'MIX' was not GRAMMATICAL correct, but yours said the same, the vacuum moves the valve hot or not. (on or off) the mix gives a constant cabin temp.
Anyway, the valve leaks coolant to the 'outside world' because the seals wear, why because it's made of plastic.
regards
richarda

[Entwood]

Sorry 'ENTWOOD' (pretentios prig) maybe the expression 'MIX' was not GRAMMATICAL correct, but yours said the same, the vacuum moves the valve hot or not. (on or off) the mix gives a constant cabin temp.
Anyway, the valve leaks coolant to the 'outside world' because the seals wear, why because it's made of plastic.
regards
richarda

Thank you for your few kind words ... you think of it how you want .. I strive for accuracy when giving information ..

BTW .. worth a read ..

http://dictionary.reference.com/browse/pretentious

[Richard A]

Ok, maybe a little harsh, I was trying to 'paint a picture', on/off valve to keep temp in the cabin constant.
I have had 4 Omega's, 3 Carlton's before them.
HBV is always the first place to look for 'unexplained coolant loss.
Entwood, sorry I had a bad day, you explained the HBV workings correctly.
regards
richarda   

[Entwood]

Ok, maybe a little harsh, I was trying to 'paint a picture', on/off valve to keep temp in the cabin constant.
I have had 4 Omega's, 3 Carlton's before them.
HBV is always the first place to look for 'unexplained coolant loss.
Entwood, sorry I had a bad day, you explained the HBV workings correctly.
regards
richarda   

Not a problem .. we all have them ..

 

[05omegav6]

Both HBVs that I've changed had hairline cracks around/near the upper coolant pipes and the base of the diaphragm housing. Different heater settings producing varying amounts of coolant loss.