MK3 Thermostat replacement using 2L MK2 Ford Focus item.

So after a post on a facebook board I decided the thermostat on my MK3 wasn't working and looked for a replacement. MX5 Parts was out of stock with 4 week lead time for the long one for the MK3 so ended up on Ebay. A hunt showed a pattern part and interestingly it also listed 2.0L MK2 Ford Focus as one of the compatible vehicles. Shouldn't be a surprise really given its basically the same engine with even the dipstick saying FoMoCo on the bottom.
I found a genuine Ford one being sold by a Ford dealership for £25.99 including delivery, a third of the price of the genuine Mazda one from MX5Parts so bought it.
My genuine Ford one for the Ford Focus arrived on Thursday and was installed last night, 1hr from start to finish. Perfect fit, temperature gauge now just a fraction below half and OMG the heater...forgot how well it can work. Had an airlock, could only refill 5 litres, I'd taken out 5.5 litres and the heater was blowing cold so I took it for a blast down the bypass with the heater on hot. 2 miles later the heater is blowing out "surface of the sun" temperatures.
My advice for those who haven't done it is to take the throttle body right out the car, not just move it to one side use a 1/4 inch ratchet with deep throat socket on and 4 inch "wobble" extension bar using blu-tak or similar shoved in the socket to keep the bolts in place when putting them back. You can see all three bolts if you look at the bottom one with your head in line with the top of the wing.
Ebay link for those interested.

Hi Conor, quite an array of options when selecting this item on MX5Parts! ( I do understand it’s not their fault but Mazda’s ) none in stock for several weeks? I wonder if that’s poor stock control or a demand for these due to them going south frequently? Anyway, thank you for an informative and money saving post! I’ll be using that when my stat lets go!


I was quite surprised too. Both long and short versions out of stock. Still as it forced me to look elsewhere and in the process save £50 I’m not complaining. Laughing