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[Bod1969]

As expressed in a previous posting, my paranoia of blown head gaskets has finally been justified by the fact my header tank needs a topping up every 100 miles or so with a half litre or so of water. Is it likey to be the HG or the HBV?
Any help would be appreciated, thanks

[sneakypenguin]

if there's no oil in the header tank and no water in the oil then unlikely to be hg. Could either be hbv, thermostat or coolant bridge (not sure if the 2.2's have this). Have a feel around the hbv first rather than taking the engine apart only to find it is the hbv

[Bod1969]

Thank you Sneaky Penguin, there is no oil or water where it shouldnt be so its a big sigh of relief. Never thought I,d get attached to a Vauxhall but this is a damn fine car!

[mathewst]

Can you see residue of water anywhere?

[mathewst]

There are several possibilities.
About head gasket and oil cooler you have a diagram somewhere on the forum that explains which is wrong.
Also one thing you can try.
Start the engine, leave it to heat up, turn on aircon and then start to check for leaks.
I had a small loss of water and couldn't find where. but when aircon was turned on car actually was pissing like a drunk man with a belly full of beer
It turned up to be a rubber hoose which was loose.

[tunnie]

1) When you top up the expansion tank, sniff the tank itself. Does it smell of petrol?

2) Any excessive white smoke from the exhaust from cold?

3) Is it lumpy on startup, but then clear?

4) Check HBV

[Bod1969]

Happily the answers are No, No, No and will do. Thanks for that.

[tunnie]

Happily the answers are No, No, No and will do. Thanks for that.

Suggests not HG then as you should get at least 1 of those, check rad for any leaks, HBV, and coolant pipes.

[OwenV6Elite]

Hi,

I had a similar problem with my V6 - my car was using a lot of coolant, but there were no signs of any leaks anywhere. I checked all the obvious places: HBV, around the coolant bridge and from the top of the oil cooler plate. There was no oil in the water, but the coolant system did seem to be overpressurising. When the engine was cold, I made sure it was filled up to the max line, and started the engine with the pressure cap off.

I checked for a smell of combustion gases in the header tank, and thought I could detect a slight whiff. When I revved the engine, I noticed a stream of bubbles energing from the small pipe that feeds back into the top of the header tank. I suspected that it was definitely a water / combustion chamber leak in the HG at this stage - and bought one of these:

http://www.uktools.com/product_info.php/block-tester-p-12508?osCsid=b63026950a5cc6107220f26c0c8536a6

which tests for gases in the coolant. It's a blue dye which goes yellow when combustion gases are present.  It's a useful test to do, before you go down the HG route and pull your engine to pieces!

Mine went greeny / yellow meaning I had a big project coming up! When I took the head off I found a leak beween one of the combustion chambers and a water channel.


Hope this helps.

[jonnycool]

1) When you top up the expansion tank, sniff the tank itself. Does it smell of petrol?

2) Any excessive white smoke from the exhaust from cold?

3) Is it lumpy on startup, but then clear?

4) Check HBV

Why does it do this if the HG's gone?

[Abiton]

1) When you top up the expansion tank, sniff the tank itself. Does it smell of petrol?

2) Any excessive white smoke from the exhaust from cold?

3) Is it lumpy on startup, but then clear?

4) Check HBV

Why does it do this if the HG's gone?

Because one (or more!) pots will have some coolant in when the engine is first started.  This will increase compression in that cylinder, perhaps dramatically. In the extreme, the pot will be full of coolant, if there's a really bad leak. That would be very bad.

Assuming the HG failure is from waterway to pot.

[tunnie]

1) When you top up the expansion tank, sniff the tank itself. Does it smell of petrol?

2) Any excessive white smoke from the exhaust from cold?

3) Is it lumpy on startup, but then clear?

4) Check HBV

Why does it do this if the HG's gone?

Because one (or more!) pots will have some coolant in when the engine is first started.  This will increase compression in that cylinder, perhaps dramatically. In the extreme, the pot will be full of coolant, if there's a really bad leak. That would be very bad.

Assuming the HG failure is from waterway to pot.

^^ what he said!

HG can leak, and let water into the cylinders, which causes it to run lumpy until its burnt off.

[OwenV6Elite]

This happened to mine - when the HG went - It would struggle to start, then run really lumpy until the coolant cleared from the cylinder - then it would be fine.

I had symptoms 1 and 3 - but didn't see all that much white smoke from the exhaust.

This one doesn't sound like a HG problem - but just had a thought - could it be a very small, pin-hole leak in a hose, in a place that is hard to see - then the water is squirted out of the hose under pressure, onto something like an exhaust part - evaporating it quickly? Is there any evidence of steam after a long run?

[Bod1969]

No evidence of steam but current investigation is now to determin if it only uses water with the heater on. Its too bloody cold and wet (steamy windows) to try to commute without heating in rainy Manchester but I'll let you all know.
I seem to remember it didnt use water the other week when it was warm here, but will have to test for definate.

Cheers Peeps!