Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob.

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Mon 1 Nov 2010 05:48
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

Hi everyone,

i have a problem with my Ford Focus, after about 10-15mins of "normal" driving the cooling fan will come on even though the temperature gauge is halfway and reading normal. The fan will go off after about 30 seconds but will come on every so often.

Also when i'm driving at speed uphill the temperature needle will suddenly jump up to over 3/4 up the gauge, when driving conditions return to normal the gauge will go back to halfway, i'm also assuming the fan is coming on.

I recently had the thermostat housing gasket replaced as i had a water leak, ever since then i seem to have had these problems. Any help will be greatly appreciated.

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Wed 10 Nov 2010 18:30
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

Just replaced the Cylinder Head Temp sensor as i was told it was this.

It still semms to be doing the same thing, wondered if it might be the thermostat?

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Wed 10 Nov 2010 23:32
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

what is the difference between the 82C thermostat and the 74C thermostat?

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Fri 12 Nov 2010 11:29
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - mikej

I had a problem with overheating under load (when accelerating uphill for example) on my old Focus and changing the thermostat fixed the problem for me.

I didn't have any obvious fan problems though - how do you know the fan is coming on when you're driving ? I doubt I'd have heard mine over the noise of the engine and other general road and wind noise.

Replacing the thermostat on my 1.8 Mk1 was a relatively easy and inexpensive job to do - the (Ford/Motorcraft) thermostat itself was around £14, plus the cost of the replacement coolant. The thermostat and housing was pretty accessible on my 1.8 - not sure how easy it is on the 1.6 I'm afraid.

I'm not saying it'll definitely solve your problem (there are other possible causes), but it's probably the cheapest place to start !

If you want more info on my particular issue, then search the forum for my username as I posted about it a few years ago.

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Fri 12 Nov 2010 20:47
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - over30
Does the engine heat up really quickly, in an unreasonable time scale? if so

Sounds as though the thermostat is starting to get stuck in the closed position, ie, you are not getting the full effect of the cooled radiator water passing through your engine block. From what you have said the effect gets worse the more load you apply to the engine. Try changing the thermostat

I recently changed the thermostat on a Fiesta freestyle with the 1.25 zetec engine, it was quite difficult to get to, had to remove the aux drivebelt, and the alternator, even then access was very restricted, not sure if the 1.6 is the same?

Edited by over30 on 12/11/2010 at 20:56

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Fri 12 Nov 2010 23:18
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

I know the fan is coming on because i can here it over general road noise when i'm at lights etc.

Since i've changed the CHT sensor the problem seems to have got worse, i'm now getting both fans coming on, and one is even staying on when the engine is switched off.

Am going to try and change the thermostat to see if that makes any difference. I hope so!

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Fri 19 Nov 2010 18:59
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

Right just changed the thermostat for a 74c one and fitted a bypass in the radiator top hose and the heater return hose, lets see if that works!

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Fri 19 Nov 2010 20:15
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - over30

just out of interest, when you are using the temperature controls, and air distribution controls on the heater panel, have you got it set so that the maximum amount of air is directed to the windscreen?

This setting automatically switches the air conditioning pump on, and causes the radiator cooling fans to operate.

Also, try running the engine at idle speed with the coolant expansion tank cap off, until it reaches operating temperature to remove any trapped air in the system. Every time you disconnect any part of the coolant system and renew a component, there will be air in the system, which can lead to overheating.

Edited by over30 on 19/11/2010 at 20:22

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Sat 20 Nov 2010 06:35
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

It didn't seem to matter what setting i had the heater on, the fan came on whenever i had the engine under load. More concerning though was the sudden jump on the temperature gauge, where it would almost go into the red.

It all started when i had a garage replace the thermostat housing because it was leaking, it was fine before that.

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Sun 21 Nov 2010 20:48
Ford Focus - Ford Focus '99 1.6 zetec fan & temp reading prob. - hamfist80

I think i've cracked it, its been two days now since i've changed the thermostat and installed the bypass and everything seems to be fine, the fans have not come on and the temperature gauge has not risen above halfway.

I'm so glad this has sorted it and i've saved myself about £200!

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