HBV??

[Omega-MV6]

Hi Guys,

Did a search but nothing really answered my question on this.

I'm loosing coolant.
Not in the oil, as oil is clean and clear.
No external leaks, so I'm guessing it's the HBV, as the car keeps steaming up.

My question is this:
On the HBV, does the coolant leak when it is on or off?
Also:
What turns the HBV on or off?

Cheers.

Matt

[Admin]

HBV is vaccum controlled.

It could be your problem, look for signs of water below it, especially round the bell housing.

More common to leak when heater is on.

[Omega-MV6]

Thanks Laidback....

I see I'll check for water peeing out the on the bell houseing..

Cheers

Matt

[Markjay]

The HBV is a valve that stops coolant from circulating through the heater matrix when the aircon is switched on.

[Craig_R]

Worst Case it could be your Head Gasket I was having Coolent Vanishing Checked everything until i got a Test Done on the Coolent System and it detected HydroCarbons meaning the Head Gasket.

Craig

[Markjay]

Worst Case it could be your Head Gasket I was having Coolent Vanishing Checked everything until i got a Test Done on the Coolent System and it detected HydroCarbons meaning the Head Gasket.

Craig

On the V6, coolant lose is due to - in order of probability - (a) HBV, (b) oil cooler, (c) other leak e.g. hose/rad/matrix etc, and (d) head gasket...

[Omega-MV6]

The HBV is a valve that stops coolant from circulating through the heater matrix when the aircon is switched on.

When It's engaged or disengaged?

It happened after I hacked... and I do mean hacked, the air con system out.

Well the system is in place, but the pipe that runs from the top right of the engine (As you look at it from the front, over the oil filler.)
to the Aicon Pump at the bottom right of the engine, I have hacked that out.

Cheers.

Matt

[TheBoy]

The HBV is a valve that stops coolant from circulating through the heater matrix when the aircon is switched on.

When It's engaged or disengaged?

It happened after I hacked... and I do mean hacked, the air con system out.

Well the system is in place, but the pipe that runs from the top right of the engine (As you look at it from the front, over the oil filler.)
to the Aicon Pump at the bottom right of the engine, I have hacked that out.

Cheers.

Matt

If aircon on, it prevents heated coolant entering heater matrix.  No point heating cabin to chill it...

[EddieX]

I beg to differ. With the direction control on 'screen&feet' and heat control about half, the screen sometimes mists up a bit. So I switch aircon on to provide dry air to the screen and misting disappears sharpish. Air coming out the vents is still warm though.

[TheBoy]

I beg to differ. With the direction control on 'screen&feet' and heat control about half, the screen sometimes mists up a bit. So I switch aircon on to provide dry air to the screen and misting disappears sharpish. Air coming out the vents is still warm though.

I was over generalising, but thats the principal...

[rpont]

The HBV is a valve that stops coolant from circulating through the heater matrix when the aircon is switched on.

I beg to differ - sorry.

The HBV is a valve that stops coolant from circulating through the heater matrix when the heating is switched off. It doesn't care if the aircon is on or not - at least on cars with manual aircon.

[x25xe]

Hope you don't mind me chipping in.

I would have thought that the Evaporator (the part of the A/C system which provides the cooling) is sited at the firt point of air flow entering the car.  In other words, the air hits this first upon entering the car.  From here, it flows over the heater matrix for heating if required.  The reason for this is to dry the air which in turn prevents (or removes) the misting as mentioned above.  In the winter, the air has to be heated somehow for this facility (which is a side effect of A/C) to be employed.  In any case, it does not matter which way around the Evaporator and Matrix sit, the effect is the same.

Going back to the HBV issue, if this is leaking, please get it sorted quickly or you will be looking at a new DIS module as well!

Just my thoughs on the matter and hope I have not offended.

[Markie]

Hope you don't mind me chipping in.

I would have thought that the Evaporator (the part of the A/C system which provides the cooling) is sited at the firt point of air flow entering the car.  In other words, the air hits this first upon entering the car.  From here, it flows over the heater matrix for heating if required.  The reason for this is to dry the air which in turn prevents (or removes) the misting as mentioned above.  In the winter, the air has to be heated somehow for this facility (which is a side effect of A/C) to be employed.  In any case, it does not matter which way around the Evaporator and Matrix sit, the effect is the same.

Going back to the HBV issue, if this is leaking, please get it sorted quickly or you will be looking at a new DIS module as well!

Just my thoughs on the matter and hope I have not offended.

Correct on evaporator, correct on HBV and knock on effects on Dis as its right below it!

[Omega-MV6]

cool, well it's definatly the HBV....

Looked on Fleabay, but they don't have any....

Any idea where I can get one from, and rough estimate on price.

Cheers

Matt

[Markjay]

cool, well it's definatly the HBV....

Looked on Fleabay, but they don't have any....

Any idea where I can get one from, and rough estimate on price.

Cheers

Matt

Vx Dealer - around £30eeesh