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[Lizzie Zoom]

I have just replaced the HBV.  I had two in stock, always ready for the inevitable need to change when water starts leaking at the back of the engine.

These are the two in stock:


The right hand one was purchased from Autodoc, manufactured in Denmark, for £17.50.  The one on the left was bought some time ago from a forgotten source.

After looking at the markings, and the apparent quality of the one from Autodoc, that was the one I decided to fit.  But, although I think that was the best one, is it really?   How can we know if the apparent build quality/markings mean it is the best?

In fact, apart from when they fail with water dripping/pouring out, what internally means one is better than the other?

I have now replaced the HBV at least once on all the Omega's I have owned, but I am still at a loss to understand what goes wrong with them.  I would love to know after all these years!

Any thoughts, knowledge, observations, please?  

[Sir Tigger KC]

You could try breaking open the knackered one you've removed? 

[Field Marshal Dr. Opti]

You could try breaking open the knackered one you've removed? 

 2 stroke petrol chainsaw.....

But don't hold the HBV in your spare hand.

What could possibly go wrong?

Apparently four finger Frankie swears by this method.

[Sir Tigger KC]

You could try breaking open the knackered one you've removed? 

2 stroke petrol chainsaw.....

But don't hold the HBV in your spare hand.

What could possibly go wrong?

Apparently four finger Frankie swears by this method.

I was thinking more along the lines of a junior hacksaw to be honest. 

[Lizzie Zoom]

Yes, fine, but if I was to saw the bloody thing into two a) am I not going to damage the internals  b)destroy the evidence of what was wrong and c) I don't think I would know what I was looking for in the internals of these magical devices ??

Anyway, life is too short now for all that.  Just thought some "expert" on here would know

[Nick W]

It's a crimped together plastic case that contains a plunger, spring and a vacuum diaphragm.


The failure points are the case leaking, the diaphragm no longer holding vacuum, the plunger sticking or some clumsy oaf knocking the vacuum port off the top(ask me how I know ). None of it is serviceable even if you could get it apart without damage.

Good luck trying to tell the difference between a good and poor quality part, especially considering how many Vauxhalls they were used on...

[Lizzie Zoom]

It's a crimped together plastic case that contains a plunger, spring and a vacuum diaphragm.


The failure points are the case leaking, the diaphragm no longer holding vacuum, the plunger sticking or some clumsy oaf knocking the vacuum port off the top(ask me how I know ). None of it is serviceable even if you could get it apart without damage.

Good luck trying to tell the difference between a good and poor quality part, especially considering how many Vauxhalls they were used on...

Thanks for that Nick. I thought somebody, like you, would know :

[Field Marshal Dr. Opti]

You could try breaking open the knackered one you've removed? 

2 stroke petrol chainsaw.....

But don't hold the HBV in your spare hand.

What could possibly go wrong?

Apparently four finger Frankie swears by this method.

I was thinking more along the lines of a junior hacksaw to be honest. 

Chainsaw makes for a better slasher film.

[Doctor Gollum]

The plastic degraded with repeated hot/cold cycles and eventually fails.

Fortunately, the Omega doesn't have much plastic withing the cooling system... The main two items are the expansion tank and the HBV and both fail and leak.

To better understand the foibles of having plastic parts throughout the cooling system, just speak to any BMW owners.

[Sir Tigger KC]

You could try breaking open the knackered one you've removed? 

2 stroke petrol chainsaw.....

But don't hold the HBV in your spare hand.

What could possibly go wrong?

Apparently four finger Frankie swears by this method.

I was thinking more along the lines of a junior hacksaw to be honest. 

Chainsaw makes for a better slasher film.

Yes they should have used one in the Psycho shower scene.     

[YZ250]

…………..
After looking at the markings, and the apparent quality of the one from Autodoc, that was the one I decided to fit.  But, although I think that was the best one, is it really?  How can we know if the apparent build quality/markings mean it is the best?

You can’t tell unfortunately, as even a batch of genuine Vauxhall HBV’s with the hologram on the packet were shite. I got 75K out of the original one but less than 5K out of its replacement. The second replacement was still on the car when I sold it, having done around 25K, so it’s pot luck really. 

[Lizzie Zoom]

…………..
After looking at the markings, and the apparent quality of the one from Autodoc, that was the one I decided to fit.  But, although I think that was the best one, is it really?  How can we know if the apparent build quality/markings mean it is the best?

You can’t tell unfortunately, as even a batch of genuine Vauxhall HBV’s with the hologram on the packet were shite. I got 75K out of the original one but less than 5K out of its replacement. The second replacement was still on the car when I sold it, having done around 25K, so it’s pot luck really. 

Thanks for that interesting and informative info

With every Omega (5) I have owned I have had to replace the HBV, and at all different mileages, reflecting what you have experienced.  The current one I have owned for 12 years now, covering over 31,000 miles, taking the total mileage from 55k at purchase to 86K now, so I am relatively happy with that.

[Doctor Gollum]

Everything that goes wrong on the Omega happens between 80k and 120k.

Carefully driven you might get more out of the suspension, but the car will have been horrible to drive for about 30k.

HBVs being the exception... They will fail randomly. Dropping them or knocking them in the course of other work, coupled with variable production qualities will see them fail out of the box. Get lucky and they'll make it to 100k.

[Lizzie Zoom]

Everything that goes wrong on the Omega happens between 80k and 120k.

Carefully driven you might get more out of the suspension, but the car will have been horrible to drive for about 30k.

HBVs being the exception... They will fail randomly. Dropping them or knocking them in the course of other work, coupled with variable production qualities will see them fail out of the box. Get lucky and they'll make it to 100k.

Thanks DG