nc thermostat replacing

hi all. my mk 3 has a thermostat problem. never maintains temperature etc. I see from geoffs faq section how to do it. BUT I have a bit of a back problem and may have to put this one through a garage /dealer.

anybody had one done OR can give an approx. price for having it done???



I also had a look at Geoff’s excellent FAQ, but four of the pictures seem to have been spammed by Imageshack and those wanted to lead me off on a wild goose chase of noisy flashy adverts. Pics for paras 4,5,8,10.
Surely that’s not right?

that’s one of the problems I spotted as well. I am quite technically capable ,but not physically unfortunately.

G’day guys

That was a lift from a post by a forum member. I can’t remember his name, but it looks like he’s deleted some pics from his picture host. Sorry, can’t do anything about it.

MY nephew will be doing it at his garage. mx5 parts so much cheaper than mazda on parts. genuine mazda as well.
as it uses FL22 coolant mazda wanted something like 54 quid for 5 litres…mx5 parts 12.07 pounds for 5 litre …and as you need 7.5 litres …starts to get expensive and that doesn’t include the labour.
hope it cures it.

What symptoms are you experiencing? Thermostat problems on the NC are rare…

I have a spare 5 ltr bottle of FL22 … depends where you are - £10.00 plus postage or you can collect… Wakefield, West Yorks.

I changed my thermostat a few weeks ago, I drained out about 5.5 lts from the drain plug in the bottom of the radiator. I ordered 2 X 5 ltrs bottles from MX5 parts (one left spare as above). I only used one to re fill the system and topped up the remaining 0.5 to 1ltr with the original that came out.

The cost of the aftermarket thermostat was £40 from local auto factors - check on the MX5 parts site to ensure you order the correct one as there are two, long & short. I was a bit tricky getting to the bolts but all sorted in the end.

And now the temp gauge does not fluctuate and the heater is a lot more efficient.

Robbie, my symptoms were the temp gauge fluctuating when driving, taking longer than usual to warm up, and the heater being below par, I had no loss of coolant the expansion tanks level was where it had been for the last 4 years, but the same symptoms were experiences by a fellow member’s car (of the same age, 2006 and similar miles, 70 to 80K) he change his thermostat and symptoms gone all running ok - and since I’ve done mine I’ve had no issues either.  

I haven’t yet checked the operation of the original thermostat in the traditional way of putting it in a pan of water & heating it up, as I don’t have a thermometer  go in the pan!


OK, it’s just that there is a modified coolant pipe available for earlier cars where the symptom is the heater blowing cold after high speed driving then coming to a stop and idling in traffic.


is there a TSB for the modified coolant pipe? although I have never had the symptoms you describe it’d be nice to know if the mod has been done om my NC.

What’s the last 6 digits of your VIN?

Robbie. my original thread as to thermostat problems. mine doesn’t get hot now, if I run down a long hill on the way to work then its cold by the time it gets to the bottom of the hill. lf I sit in traffic it will get hot ,but soon drops right back to about two bars after a few minutes . got all the parts now so will get it done anyway.
ps, the thermostat complete with cover from mx5 parts DOES come with a don’t need to order one separate. and as they are fifteen quid…(will send mine back)

We’ll certainly was a problem with the thermostat.stuck completely open. Changed and all fine now. Took just over the 5litres of coolant to fill. We also changed the serpentine belt as there was signs of "shredding"in a couple of places. Maybe caught something at some point.
So I still have about 4 litres of coolant left for top ups. Mind you never had to before.

Sorry Robbie - only just noticed your reply!


the last 6 of the VIN are: 124510