Too cold now!

[Verity Ferret]

Dearest Friends,

I'm back! After writing "Which thermostat?" and then "Still Overheating" the car is finally up and running. ....well, had a few probs since last post....but I just have a teeny tiny issue now.....

Can anybody help please? I have to run my 1.6 4 door with no thermostat for the time being but I have noticed that the radiator fan is kicking in a lot more than before. I'm not 100% as I never really noticed but now the temp gauge (eventually) gets to normal operating temp, stays for a little while, drops back to practically zero, which is better than the mentioned topics, then climbs again. It does this whether I have internal blowers on windscreen or cab and pretty much does it for the entire 40 minute trip to work. needless to say, it's been quite cold!
Is this because it has no thermostat, therefore cannot regulate properly or is the fan faulty? Could I have have broken or damaged something when I replaced radiator?

As mentioned in earlier topics, these are the bits replaced: thermostat, hoses, header tank, cap, waterpump, cylinder head temp sensor, all because of overheating. Turns out that replacement thermostat is also broken which is why I don't have one in - run outta money!
Please help...
Many thanks
Verity

[Stoney871]

You need a thermostat in to balance out the temperature fluctuations.
No thermostat is why the fan is kicking in and then the temperature is plunging.

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[nazsky786]

There should be heat in any case after a 40min drive. Saying that your driving, fans on inside and tax fan on. Coolant is ice cold.  

The thermostat opens at a set temperature which is mechanical,  the sensor should then be able to pick up the temp and decide if the fans need to turn on or not.  

Since no thermostat as Stoney put you have a free flowing system, so the coolant never gets to the temp it needs normally around 80-90. Any heat just gets blown away. And with driving your car would be in open loop, you should be using more fuel. 

Since the car never reaches the temp it needs the rad fan shouldn't be on.  Unless your using AC.  

You state an overheating issue has the engine been check for headgasket failure? 

[Verity Ferret]

Thanks guys, looks like I'll have to find a thermostat - one that works and is like for like to the original. Haven't found it yet, even with part number!

AC has not been used in about 5 yrs as needs regassing - the ac unit is also disconnected as I thought that was one reason for initial problems as constantly switching on. The head has been pressure checked and there is no evidence of gasket failure. The cars runs sweeeeet!

I'm just confused as to why the rad fan is switching on every time I switch blowers on.

Thank you friends, I'll see what happens when I fit thermostat

[mjt]

On 2/20/2020 at 9:13 PM, Verity Ferret said:

the temp gauge (eventually) gets to normal operating temp, stays for a little while, drops back to practically zero, which is better than the mentioned topics, then climbs again

A point to bear in mind is that the temperature gauge is driven by the ECU and is not directly related to the signal from the temperature sensor. When the signal reaches a predetermined value the ECU moves the gauge to the 'normal' position. What may be happening is that without a functioning thermostat the egine temperature is hovering around the critical value at which the ECU decides it is at working temperature so small variations take it above and below this threshold.

I don't think the engine will be working open-loop because this is based on the signals from the Lambda sensors in the cat, which shouldn't be affected by the lack of a thermostat.

[nazsky786]

Seems like you need to go to Ford,  buy a new thermostat, install it. ( the nipple must be located at the top when installing)  Put everything back together and fill the coolant system with correct coolant.  Run it with the bottle cap off  and keep filling to the max mark. Once you see all the bubbles gone and the coolant stops lowering. Rev it at 2500 rpm for about 2 mins.  Keep an eye on coolant level.  

Let it idle again 1 min shut the car off after. Put the radiator cap on a drive it as you would. After a day driving check and if needed top up coolant.  You shouldn't need to fill coolant after this fill up.  If you do have to you have a leak. 

Also does the engine start first time everytime cold or hot?

Lambda sensors are only 1 part of a list of sensors the ecu uses. The lambda sensor would show the car burning more fuel to heat up an engine that it thinks is being driven in the north pole.  

Also if you have diagnostic reader check at what temp the car turns on the fan unless it turns it on thinking its over heating.  If you have high temps on cold engine you may have a faulty temp sensor,  but that normally has the symptom of hard start when hot.  

Also you had the head removed from engine??  Was the head gasket etc replaced when rebuilt?

[Verity Ferret]

I went to Ford with part number and they wanted an astonishing amount of money for the thermostat! I knew that it would be pricey, but I was completely dumb founded by the price! A couple of hours on eBay, and I have finally found a like for like unit! Phew!

the car starts perfectly,1st every time, hot or cold never missing a beat. I have never had the head removed, it was pressure checked and there is no evidence to suggest a head gasket failure - all the car guys are adamant that the head is good. They just disagree about this thermostat issue!

I'm afraid I don't have a fancy enough diagnostic reader to be able to read temp......could I just stick a thermometer in the header tank?!

Have noticed that the choke is on for a lot longer, so I spose the fuel consumption has gone up - haven't paid any attention as so happy that the car is working again!

many thanks everyone, I will keep in touch to let you know what happens....wish me luck!