Am I hot or wot?

[AlabamaShrimp]

My fiesta has been getting hot enough to need the blower on full to stop it over heating for some time and the electric fan on works but won't switch on

 

this is my radiator

 

 

It's not leaking but has lost a lot of fins at the top and damaged in other places.

 

I took it off last week, flushed it and the whole engine out, then refilled with antifreeze.

 

It looked like this straight away

 

 

So twice it's got really hot since temp goes to nearly red

 

 

I panic but the heater on full blast, the thermostat must open, and then it settles on about this

 

 

And proper smells hot. So apart from a new radiator, fan switch and more antifreeze is there anything else I can do?

[dugong]

Probably* not. 

*Buy a 305 van? A R8 416? Pedant Top Trumps?

[Micrashed]

Backflush cooling system with garden hose - often clears shit out.

 

Water pump ok? Still got all its blades?

 

try Water Wetter as an additive to the coolant.

 

I seem to remember my mk2 used to head north on really hot days. Never went into the red though.

[AlabamaShrimp]

Already used the hose on it and I aren't taking the water pump off as I know of the twat will never go back on right

[Bobthebeard]

"My fiesta has been getting hot enough to need the blower on full to stop it over heating for some time and the electric fan on works but won't switch on"

 

Bit confused. Does the electric radiator fan actually cut in and run when it should?

[AlabamaShrimp]

Sorry meant the heater fan in the car has to be switched on so full blast on hot so at least one radiator is getting air through it. The one in the engine won't turn on. I tested it and it does work when you bypass it's sensor

[Wackeldackel]

Start from cold and feel the rad as it warms up for hot and cold spots which may suggest its clogged inside. Also feel top and bottom rad hoses, should be a temp difference until thermostat opens. Possibly take thermostat out and boil in a pan of water to make sure its opening?

[tooSavvy]

Ah!... Cluedo

 

TS

[Heidel_Kakao]

Wire the radiator fan to a manual switch if it's not coming on automatically?

[richardmorris]

Got the merc up to 110 today - stuck in traffic in west London. Can anyone explain how viscous fans work please? Do they have more than engine speed capability or do they just run constantly the same speed?

[Bobthebeard]

Sorry meant the heater fan in the car has to be switched on so full blast on hot so at least one radiator is getting air through it. The one in the engine won't turn on. I tested it and it does work when you bypass it's sensor

I think you may have just answered your own question right there.....

Duff sensor on radiator fan. The heater fan is not designed to cool the engine. Just dumps heat into the car.

[AlabamaShrimp]

I know the sensor must be kaput it's just after messing with it it seems to be getting a lot hotter then normal. I've checked all the pipes and don't think I have a vapour lock

 

Will just have to replace all the bits and hope for the best

[brickwall]

Got the merc up to 110 today - stuck in traffic in west London. Can anyone explain how viscous fans work please? Do they have more than engine speed capability or do they just run constantly the same speed?

 

 

Basically a liquid clutch.http://www.freeasestudyguides.com/performance-viscous-fan-clutch.html

[Wackeldackel]

What brickwall said.

 

When the engine is cold if you flick the fan blades to the side sharply the fan should stop after half a turn or so. If it spins freely the viscous part of the viscous coupling has deteriorated. Apparently they don't like being stored horizontaly either as the viscous fluid seeps out or where it shouldn't go.

[spike60]

Got the merc up to 110 today - stuck in traffic in west London. Can anyone explain how viscous fans work please? Do they have more than engine speed capability or do they just run constantly the same speed?

My 2000 Merc had a progressive electric fan, the hotter the faster not just on/off as normal.

[Ghosty]

Those dash pics bring back some fond memories of the two mk2 Fezzes that used to be in the family.

Cheers! 

[richardmorris]

Thanks for the info. Seems to be as described - ie don't move much when stopped.

[New POD]

Sorry meant the heater fan in the car has to be switched on so full blast on hot so at least one radiator is getting air through it. The one in the engine won't turn on. I tested it and it does work when you bypass it's sensor

 

 

Fit a switch in the engine bay, and put it on at the start of your journey (I did this on a mk3 escort in 1989, and only had to turn it on twice in the summer.)

[Squire_Dawson]

Try cleaning all electrical connections first - could be as simple as that and work from there.

[AlabamaShrimp]

Cleaned the switch already

[Geep]

When the Fiesta first came out we had customers coming in saying they were over heating. They weren't, it was just that the temp needle climbed until the fan cut in, then dropped again. People were used to the old fixed mechanical fans where the temp gauge stayed central.

 

Let it idle and wait for the electric fan to cut in then see if it cuts out after a while. The temp gauge will read high until it cuts in, the main issue is making sure tha fan cuts in. It should do before it reaches the red. My 2.0 Frontera sport* climbs high and even though I know it works as it should, it can still be a bit bum clenching in traffic. Just as you get to the sweating stage, the unmistakable whoosh starts up and the engine dips a bit as the load goes up. Then it's calm down time until it does it again.

 

Maybe it's why they've dome away with temp gauges a lot these days? After electronic jiggery pokery to get them to stay in the middle, they were useless as accuracy was out out the window? Or maybe it's just cost.

[Felly Magic]

TBH fit a new fan switch, not normally an expensive job, then give the whole lot a damn good flushing out both ways for at least 15 mins

[AlabamaShrimp]

Update now I've found where I left the pics

 

After getting some new bits a couple of weeks ago I took it all apart

 

Stripped, cleaned and painted the fan

 

 

Made a very nice gasket

 

Then out it all back together again with the right amount of antifreeze and checked for vapour locks

 

Gets to about half way on the temp gauge now and the fan hasn't come on but it's a lot better than it was