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[monza789]

hi guys....my 97 Omega 2.5 has a very poor heat output in cabin.  I have changed the HBV and its still not getting above luke warm at best.
If i switch blower on anything above speed setting 2 then its even worse...in this weather its not cosy in the cabin.
There are no external water leaks anywhere and its not using coolant.
Any ideas?

monza

[Mike Collins]

Are both pipes supplying the heater hot?

If the lower one is cool,I have a similar problem, so far I have flushed out heater matrix, replaced HBV and refilled using Vauxhall's method of removing the upper heater pipe.

The only action so far which has helped a little was to fill with the upper pipe disconnected from the HBV untill liquid appeared.

My thought is the HBV seems to be the highest point in system, could it be an airlock?

[Rank]

Same problem- just discovered it's the secondary coolant pump, having changed the water pump already and flushed the heater matrix!.

Symptoms were poor heat output from heater, a tendency to overheat in traffic (although the radiator fan cut in to bring temp down again) and for it to keep switching back to petrol from LPG especially in cold weather.
 The coolant pump is over £100 from vauxhall dealers I've just been told.

Hope this helps

[mark.adams]

Do all omegas have secondary coolant pumps??

[Kevin Wood]

That's interesting. I'd assumed the secondary coolant pump was only used for heating using residual engine heat when the car is parked with the climate on. Maybe it's used during running too?

.. or maybe it had just clogged. :-/

If it's not actually running during normal operation I'd remove it and see how the heater works. Heating the car when parked is not worth 100 quid IMHO!

Kevin

[Mike Collins]

As far as I can work out, all V6 have a secondary coolant pump at top left of the radiator. This runs after shutdown, if the temperature is high enough, to lower the head temperature. If it fails you get coolant overflow after shutdown.

Facelift cars after some point had a second pump under the expansion tank, this is to allow the heating to function after shutdown.

Pressing auto with the engine off turns the system on for as long as there is heat in the block.

I don't know if this second pump runs at any other time.

I doubt a 97 car would have this pump.

[bigdods]

Facelift cars after some point had a second pump under the expansion tank, this is to allow the heating to function after shutdown.

Pressing auto with the engine off turns the system on for as long as there is heat in the block.
.

According to the manual my 2000 Elite 3.0 has this feature. I've never tried it though...

Re: the original post, are you relying on the climate control to set the temp i.e. leaving it on say 22 then finding no hot air coming out ? If you set it to Hi on one side do you then get toasty hot air or is it still cold ?

[Big_Roger]

Hi All,
Thank goodness for an explanation of how all the elec water pumps are supposed to operate.

I see a lot of posts generally about the cabin heating system, although mine seems to be very good, they do seem to be a problem and a bit over complicated.

Can anyone tell me if the HBV modulates to control heater, or is it just on or off all the time ?

Roger

[Kevin Wood]

As far as I can work out, all V6 have a secondary coolant pump at top left of the radiator...

Yep. This is correct and the pump on the rad. has nothing to do with the heater. It runs when the engine has been shut down AND the coolant is hot enough to cause the cooling fan(s) to run.

The pump under the expansion tank is connected only to the climate panel as far as I can see, so I don't believe it would have any other function than to circulate water through the matrix. Question its, is it used during running to supplement the flow from the engine coolant pump or only when parked with the climate on?

Can anyone tell me if the HBV modulates to control heater, or is it just on or off all the time ?

There are flaps to divert more or less air through the heater matrix so these are used individually (left and right) to control the temperature. I would imagine the HBV only closes when there is no demand for heat to the cabin.

Kevin

[Mike Collins]

I am sure Kevin is right about the HBV being on/off.

I have run our 2.5 with a vacuum gauge on the HBV line and have only seen no vacuum when heating, or around 4 inches when closed.

I still have not managed to get a good flow through the matrix though.