Technical Over Heating

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Technical Over Heating

Paladin

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Feb 8, 2009
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Hey guys.

Im having a really annoying problem with my UNO. the car starts fine and runs well. The problem comes in once the car has been running for about ten minutes. The temperature just keeps rising and the radiator fan doesnt switch on at all!!!!!!!!! Even when i reach the red lines!!!!

I have changed my thermostat, my temperature gauge on the cylinder head, the fan switch, the fuse is fine, the grey block thing on my fuse box is also new and ive also hooked the fan straight up to the battery to test it and the fan works under direct current.

Im a student and i need this car to work before varsity starts. The car has been standing for some time, as it was given to me before i had my license, but as i said, everything else works well.

If anyone can help, or at least point me to someone who can, pls let me know. Thanks a lot, guys.

Paladin
Im in the Cape Town area.....
 
Hey guys.

Im having a really annoying problem with my UNO. the car starts fine and runs well. The problem comes in once the car has been running for about ten minutes. The temperature just keeps rising and the radiator fan doesnt switch on at all!!!!!!!!! Even when i reach the red lines!!!!

I have changed my thermostat, my temperature gauge on the cylinder head, the fan switch, the fuse is fine, the grey block thing on my fuse box is also new and ive also hooked the fan straight up to the battery to test it and the fan works under direct current.

Im a student and i need this car to work before varsity starts. The car has been standing for some time, as it was given to me before i had my license, but as i said, everything else works well.

If anyone can help, or at least point me to someone who can, pls let me know. Thanks a lot, guys.

Paladin
Im in the Cape Town area.....

Check for power going to the radiator fan thermoswitch. It should be live with the ignition on, and the thermoswitch will activate the fan once the coolant has reach a certain temperature (approx. 90 degrees on the temperature gauge).

If you have power going to the switch and you're sure that the switch is ok, then it sounds as if you have an earth problem. I had this exact fault when I first got my Uno 70SX, the radiator fan wouldn't switch on even though there was power going to the switch. I earthed the switch directly and the fan worked, thus I deduced that the earth lead was faulty. The fan switch earth lead is connected to the multi-pin earth block beneath the battery and behind the passenger headlight. I located the lead, disconnected it, cleaned the connections on both the lead and earth block, re-assembled them and then the fan worked absolutely fine after that.

So I'd suggest a simple wiring check and cleaning of connections first and you should be on the way to identifying the fault and hopefully correcting it (y)

Welcome to the forum too! :wave:
 
Hello Paladin,

I agree with the advice above. Just additionally:
- If you turn the heater on full, do you get hot air out? I know it's summer and hard to tell, but if the air seems like ambient temperature, maybe the cooling system has a severe airlock and there's insufficient flow to the heater or the radiator.

Also it wasn't clear to me whether this overheating occurs when you are driving the car, or only when it's stationary. Definitely, you need the fan if the car is stationary and overheating. But when you are driving, the temperature should at least drop a bit. If not, then I think you have some other problem than just the fan.

Is the system retaining the coolant and is the coolant staying clean? I use the term 'coolant' because you should always have antifreeze (green) or corrosion inhibitor mixed with the water in the radiator. If you're having problems with coolant spraying out after only a few minutes, then I suggest that you possibly have a blown head gasket :( Not a huge job and parts are not terribly expensive, but it needs urgent attention if you do.

Give the radiator a reverse-flush (with a hose hooked up to an outside water tap etc.) - it's always possible that it's blocked. Suspect this if the water was really brown (rusty).

The final possibility is a faulty water pump (so, no circulation in the cooling system = engine overheats regardless of radiator fan coming on). Obviously, get the fan working first (if it's not already). The water pump is an unlikely failure (it's driven by the cam belt on the FIRE) but it is just possible that the impeller (blades) has come away from the shaft - or something strange.

So - let us know how you get on with some of these checks and thoughts. :)

Cheers,
-Alex
 
Ok thanks guys.

You guys have given me some things that i havent thought about yet:eek:...Ill try these options as soon as i get home!:D! Ya, the overheating happens when the car is stationary, as i have only just licensed it and i need the fan to work for roadwarthy!:cry:

But once again, Thanks for the advice and the welcome :). :slayer:
 
Under the distributer, on the right of your engine, you'll find the thermostate it housed inside the head you will see the water pipe from the radiator attached to it, to remove it you'll need a 13mm spanner, it might be smaller and the engine needs to be cold.
Bet you its blocked even new ones don't always work
the hot water is'nt getting to the fan sensor that why it won't come on
when the car is hot
i had this problem and it cost me a new head gasket, before i read the manual and found out were the BLASTED thermostate was on a uno
my advice, if it hot were you are, brake the old one open to let the water flow free and put it back.
She may run a little cooler but it will give you time to get a new one.
you might also want to try and wash the head water ports, take the thermostate out and use the garden hose to try and blow the water ports clean. N.B. UNO's love coolant, stops the ports from clogging up, you could try putting clean water in and then adding about 20ml of brake fluid, run her like that for a bit to clean the water ports,the change the water and add coolent,
O you might wan't to have your water pump pressure checked if the pressures to low the thermostate also won't open.
 
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