ZX Diesel heater blower runs cold when on hot!

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xsive33
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ZX Diesel heater blower runs cold when on hot!

Post by xsive33 »

I've just purchased a 1992 ZX turbo diesel for £307.99p!

It has 107000 on the clock and is in pretty good nick. The only fault I can find with it, is the blower sometimes loses it's heat when it's switched to the red/hot position. The water temperature guage stays just under the halfway mark normally and doesn't move much from there.

I had a look at the radiator coolant level when it was stone cold this morning. As I unscrewed the cap it was under pressure, letting out a small amount of orange water. The rad looks relatively new (as confirmed by the previous owner. The coolant level is still at the top of the rad.

I'm wondering if there's some sort of air-lock in the system?

Has anybody any ideas?

Cheers.
Peter.N.
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Post by Peter.N. »

Could be that you have an air lock or that its clogged with rust. Try disconnecting the heater pipes and flushing it through with a hosepipe. When you reconnect the pipes fit the bottom one first and fill the reservoiur until water comes out of the pipe from the heater, that will make sure there is no trapped air. Make sure also that the pipes are on the right way round, if its possible to swap them, the feed in should be the bottom one.

If you have pressure in your cooling system when cold it would seem that the head gasket is leaking, but as long as its not continually blowing water out I wouldnt worry about it.
xsive33
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Post by xsive33 »

Thanks Peter, I'll give that a go.

I think it'll need the coolant/antifreeze changing anyway as the colour of the water was pure rust orange!
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Clogzz
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Post by Clogzz »

The orange colour may be normal, it’s Citroën’s original glycol coolant, which is orange.

Story here:
http://www.aussiefrogs.com/forum/showpo ... stcount=20
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xsive33
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Post by xsive33 »

Hmmmmm.....

Never seen that before.

Bugger! Is it rusty water (but it's a new rad) or is it Citroen's own anti-freeze/coolant?

Now I need to check the viscosity of the glycol/water content.

Cheers.
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Post by Clogzz »

If it’s the orange coolant, it will be transparent, and of a uniform colour and clean look.
That’s assuming it hasn’t been in there since 1992, not likely with a new radiator.
If it’s rusty water, it will have an opaque, dirty look.
The coolant has a slightly sticky feel, while the rusty water is just watery.
Wet a tissue with the ‘fluid’, and spread it on a surface to dry.
The coolant won’t dry for long, while the water will dry in the time it takes for water to dry.
You may also have the new type of coolant without glycol.
It’s also orange, but I know nothing else about it.
This topic talks new coolant, 3.6 Megabytes, too big for my 3 KB/sec:

http://www.frenchcarforum.co.uk/forum/v ... php?t=8275
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Coolant

Post by mrjohnson »

If you can't measure the specific gravity....

Extract a spoonful or so of coolant.

Bung it in a jar in your freezer. After a few hours....

Liquid - stands a chance of being OK.

Slushy - some antifreeze, but probably not enough to stop corrosion.

Solid - Water or much too weak antifreeze mix.

Cheers

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Post by citroenxm »

Hi

Strange, my Partners 306 xtdt 1994, has a similer problem!

She has warm air from the face vents but stone cold from the window and foot vents, even with the temp on MAX and regardless of the direction flow!

Need to get it investigated as its cold days and nights (so she says)

Regards
citroenxm
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Post by jeremy »

I notice that the original post states that the problem sometimes doesn't occur. The ZX heater is an air blender - and the matrix gets hot all the time and does not have a water valve. This means that its output is controlled by the flaps - and I wonder if the problem lies there.

Classic for a blocked matrix is for the thing to blow hot air which rapidly cools . You may be able to feel a cool return hose which would confirm the matrix theory. If this is the case I'd first trace the pipework and look for somewhere convenient to disconnect it (not the special twist clips on the matrix as they are difficult and may break) and then connect it to a hose and see if I could flush it. Be careful - garden hoses can run to 90 psi - which is about 6 times what the cooling system runs at. If its really clogged - you'll have to replace it - dash out job on a ZX.
jeremy
xsive33
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Post by xsive33 »

Thanks for your comments.

Since then, the blower is running cold at all times, temp guage stuck on cold until 15minutes into journey when it shoots up to just under the red. When I pull over, coolant is boiling over.

I changed the thermostat and the problem still exists.

A thorough flush through seems in order.

I'm now hoping the head gasket isn't knackered as a result of overheating!
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Post by Clogzz »

Probably low coolant caused by air in the system.
The top heater hose has a vent valve.
Open the valve with the engine running, and close it when fluid comes out.
If air comes out before the fluid arrives, that’s what it was.
Check the fluid level in the header tank after that.
2002 C5 2.0i AL4 230,000 km 76372389
xsive33
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Post by xsive33 »

Well, the head gasket has been replaced and left me a few hundred quid lighter.
I wouldn't say it blows out red hot air but at least the engine doesn't overheat!
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