Print

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

[sophos9]

Thats a lot of water to lose!

Personally I would take car for a spin, get it up to temperature, top up coolant, then let it idle. Would get it up on stands and get under with a torch and watch for the steam show.

Lots of places for coolant to leak, HBV, oil cooler plate, coolant bridge, heater core etc.

Look for evidence (white/coloured stains) of a leak, HBV will spill down rear of engine (and all over your DIS pack leading to rapid failure), check air con drain (above gearbox)

Another place to check is the radiator drain plug, the washers perish...

[Entwood]

Non-consistent loss of water is, I believe, often the HBV as it responds to changes in demanded temperature in the cabin and the outside temperature... it therefore sometimes leaks, sometimes doesn't  

What can help is to leave the car idling at normal temperature and make several large changes to demanded cabin temperature, leaving things to run between each change, and watching the HBV area like a hawk. It is then, sometimes, possible to see a leak as the HBV cycles to change the cabin temp.

Did this on my mates troublesome beast and sure enough, the HBV leaked when supplying HOT water (initial heating of cabin), but not once the cabin warmed up and the HBV backed off to maintain temp.

HTH

[sophos9]

Heater core also has the potential for conditional leaks. Aircon on will reduce or stop a leaking matrix as the demand for temperature stops the circulation through the core...

[DaveyDavey]

Thanks chaps.

I don't use the aircon at all at the moment (we'd need some decent weather for that) in fact I think I have only used it 4 or 5 times all summer(?). Certainly not used the aircon in the last couple of weeks since this issue first arose.

Now then, my next question would be: Where can I find a new HBV? Is this something I have to source directly from my local Vauxhall garage?

[sophos9]

Diagnose then buy mate  

Main stealer or give Autovaux a call....

[Entwood]

It's also possible that you only get the leak once the system is on high temperature/pressure .. ie a decent length run.. this may well point to a header tank cap problem as there is a relieve valve built into that. If it is relieving early it could be the source of the problem.

[DaveyDavey]

Success!! Okay, only 50% success in the grand scheme of things but my I am happy as I have finally diagnosed the problem as definitely being the HBV. Well I'm as certain I can be at any rate  

So I will be picking up a replacement later on with a view to changing it at the weekend. Thanks to all so for your replies, they have been most helpful in the diagnosis.

My final question though: How long does it take to change the HBV?

[Andy B]

.....
My final question though: How long does it take to change the HBV?

You should be able to comfortably change it in about an hour. Remove wipers, scuttle & wiper mechanism to give you a reasonable amount of room to work in.

[DaveyDavey]

Thanks Andy, I might be able to borrow my friend's garage for that if it only takes an hour or so. Plus I might be able to rope him into helping too  8-)

I'll be printing off PeteG's "How-to" for the HBV shortly as it looks pretty comprehensive. Just need to borrow some Torx bits and a couple other tools that I don't posses to make my life easier.

[sophos9]

Nice one mate, hope it all gets sorted!