uno heat problem

I have a strange problem. During the drive in the city radiator fan switch on and off. But when I stop and switch off car( engine is hot), radiator fan never turn on.
Antifreeze then start to leak on radiator cap (there is much presure). the car is uno 70sl with 1301ccm.(1986).
sory on my bad english.
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does the car overheat?
perhaps the thermostat or the thermoswitch which turns the fan on

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On 17 Jul 2003 22:36:49 -0700, snipped-for-privacy@netix.co.yu (pedja) wrote:

Like I said you may be switching off the fan/thermostat supply when you turn off the ignition.
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(pedja) wrote:

I check that too, radiator fan works when engine is off.
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Fan switch and fan motor have latching connectors, ease the latch and thet pull off. Then it's just top and bottom hoses and a couple of clips to remove the radiator, to give it a good flush through with the garden hose. With a large bowl underneath you can collect/save the antifreeze as you ease the bottom hose off, better to refill with fresh though. You can also give the radiator a good shake when full of water, that stirs up the rust and gunge. A cleanout of the cooling system every 4 years or so is a good idea, a lot of brown sludge builds up in that time.
While you have the hoses undone turn ON the heater tap to ensure free flow and put the hose on one of the smaller heater pipes to flush out the heater matrix. I usually flush both ways down both pipes.
Uno Mk 1 or Mk 2, year?
On 20 Jul 2003 23:02:20 -0700, snipped-for-privacy@netix.co.yu (pedja) wrote:

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I flush radiator, but problem goes on. (When turn off warm engine, level of antifreeze start to raise and finaly start to leak on tank cap.)
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Maybe it is just overfilled. If you fill the radiator to the top, then when the water get hot, like a thermometer, it expands, and comes out from under the cap. As long as it is below the minimum coolant level mark (and with the Uno you may need to shine a torch into the tank/radiator to check) it will be ok. After a few days driving it will settle and so long as it settles below the Min mark all should be ok.
Some cars/lorries have separate expansion tanks with much more capacity than the little reservoir/tank that is part of the Uno radiator. Being a separate tank means that the coolant in the separate tank doesn't get hot and expand plus the separate tank can have a level sensor working a warning, low coolant level, light. Think the Talbot Samba had this arrangement. I also, many years ago, fitted it to my Mini, using a s/h 1100/1300 tank.
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I assume that the Uno doesn't emit white smoke when started ????
Being a 1301 ccm the pots are bigger and the gasket web between them that much narrower.
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The problem is solved... flushed radiator second time and for now it is fine (outdoor temp is 33-37C).
thanks
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Trouble with radiators is that someone may have used Radweld (or worse) and blocked half the tubes solid, including a few in the heater matrix.
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