disappearing coolant

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froggy
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disappearing coolant

Post by froggy »

My, 1995 zx diesel, is losing coolant !
I fill it up to maximum on the exspansion bottle, then usually after a few miles of driving the coolant is at the minimum mark . It never drops below the minimum mark, and there is no external leak.
Anyone got any ideas.
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Post by spider »

That could well be normal.

If you fill it to max when its cold that is overfull in effect, so it may push some out when it gets hot.

If you wanted a practical example, my 205 if I fill it to the normal mark it will push a bit out, however it never will drop below say an inch below that ever. Adding coolant above normal is the same, it will "lose" that bit and just sit slightly below normal when cold. When hot (usual cautions with pressurised coolant systems = drop in pressure when you take cap off = coolant boils = easy to burn yourself) it is higher.

If it does not drop below minimum I would suggest that's normal. Let it sit at minimum (after all, its still in the 'safe' area) and just keep an eye on it.
Andy.

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Post by Chlorate »

I'm not sure if I would say coolant dropping to the minimum mark in a few miles was normal. That's a heck of a lot of coolant to lose so quickly.

Sure if you completely top it up it'd drop a little bit, but not much below the maximum mark.

How much pressure is the coolant system under after the car has been driven?
You can tell by grabbing hold of the big hose that connects to the top right of the radiator. It should be a little firm.
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Post by wrinklet1 »

Hi, just have a look at the hoses on your system and see if the is what looks like a tyre valve cap on it somewhere. If there is, connect a tyre foot pump or elec tyre inflatore to it and put a few psi into the system, ideally when it is warm but not hot. If you have a leak the pressure will force the water out from where it is leaking. Maybe a core plug hase corroded?
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Post by Xantidote »

Has it always run with coolant at a particular mark, and you're now saying that things have changed?

May be that the pressure cap is weakening, and now allows a bit of coolant to escape via the overflow pipe(presume you have one?). Easy to check if losing coolant this way by placing old beanz tin to catch any escaping coolant. Had this on my '95 Xantia TD a few years ago.

My Xantia doesn't like coolant at max level, and it very slowly drops to around the minimum level, where it sits month in/month out (though funnily enough, in this case, never see a trace of the escaping coolant in the tin)
Martin

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Post by spider »

Xantidote wrote:My Xantia doesn't like coolant at max level, and it very slowly drops to around the minimum level, where it sits month in/month out (though funnily enough, in this case, never see a trace of the escaping coolant in the tin)
This is more or less what my 205 does and always has done. It never gets below minimum however.
Andy.

91 205D-Turbo, gone but still missed
02 106D, TUD5B, gone but not really missed apart from the MPG
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