K12 Thermostat - which one?

Morning everyone. Me again! My wife's K12 1.2 Acenta seems to be getting a bit warm on only short journeys (not been very far yet) so I was thinking I'd change the thermostat as a precaution. Only problem is that there are so many different ones available. Different brands; wide range of prices; some smaller/larger than others; some 87°C others 88°C. I'm a bit lost to be honest! Does any of this matter? Is there anywhere I can go to make sure I get the correct one please? TIA :)
 
Any of them will work as long as it falls between the figures in the image (86.5-89.5)


thermostat.jpg
 
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smoth1976
Thanks very much for that Mad_mike :)

I don't suppose you can offer any advice on reliable brands/makes and/or the size I need can you?
 
I've not changed the one on my Micra, but did my Audi A4 last year and from memory I used Quinton Hazell
I can't say I have ever had issues with thermostats in the past, and generally just order whatever is cheapest, or take whatever my local motor factors have in stock.
Regarding your question about size, I don't understand. If you order a Nissan Micra thermostat, it should fit correctly anyway. Just be sure to check it's for the same year and engine size.

Are you sure it's the thermostat is the issue?
Is the cooling fan cutting in when it idles at high temperature?
 
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smoth1976
If I'm honest, no I'm not sure I even have a problem! It just seems to be getting very warm (the o/s headlamp feels hot to touch) on short journeys but I've not heard the fan cut in so this is a 'precautionary first step'.

In terms of sizes, the dimensions on the below are both different but both appear to be correct for the K12 1.2 2008!?

1599664086717.png
 
That's weird alright
Just looked on Autodoc using the OEM code and the majority of them appear to be around 53-54mm diameter, and by the way, the Gates one is under a tenner on there
Normally, a thermostat should only cost around a tenner. Don't think I've ever paid more for one in my life and they all worked fine!

No point in changing it if it seems ok though
Best thing to do is start the engine and let it idle for maybe 5 minutes
For the first while, the top pipe on the radiator should stay cold
If the thermostat is working correctly, once the coolant reaches around 87-88 degrees, it will open and the top pipe will heat up
Assuming that's ok, leave it run for maybe 15 minutes and once the temperature reaches even higher, the cooling fan should cut in at the front
Best to check those before doing anything
 
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smoth1976
OK, so tested, but before I started I noticed the coolant was low so topped up to the max line and then started the engine - with a few minutes I could feel warmth in the top pipe which didn't seem to change for the duration of the test - after 25 mins the fan had still not kicked in so I switched off! - does that indicate a faulty thermostat? Or something else maybe?
 
The coolant system is sealed, if it needed topping up that can only mean one thing, you have a leak, will leak faster when the car is running because the water pump is somewhat obviously pumping water around.

No fan after 25 minutes :unsure:...Does the coolant look normal, not like an oily watery mayonnaise mix?

Is the heater warming up normally?

No fan after 25 minutes indicates the fan isn't working, could just be a fuse, check that first.
 
Unless you live somewhere really how or really cold, get the standard one.

There can be many things affect the running temp, like waterpump, radiator, general crud in the system, fan not kicking in at right speed.
 
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smoth1976
The coolant system is sealed, if it needed topping up that can only mean one thing, you have a leak, will leak faster when the car is running because the water pump is somewhat obviously pumping water around.

No fan after 25 minutes :unsure:...Does the coolant look normal, not like an oily watery mayonnaise mix?

Is the heater warming up normally?

No fan after 25 minutes indicates the fan isn't working, could just be a fuse, check that first.
The fuse looks fine (now I've found it) and I've realised the fan comes on when the A/C is switched on so I know that's working now. I'm thinking it might be the coolant temperature sensor so thinking about replacing to be on the safe side. I'm now also a little concerned about the fact the coolant level was very low. It looks a good colour though and the level hasn't dropped in the last couple of days so a bit puzzled. Might be time to take it to someone who knows what they are doing I think ....
 
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smoth1976
Replaced the coolant temperature sensor this afternoon and the fan now kicks in and it doesn't smell so hot - happy days - thank you to everyone for the help and advice here :)
 
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