- My model of MX-5 is: _2010 1.8 NC3 48K miles_
- I’m based near: __Durham
- I’m looking for technical help or recommendations on: __Car Heater issue.
Until recently the car heater has worked perfectly, but following a coolant change the following issue has developed. ( genuine Mazda coolant was used from dealer)
When driving the air is hot, or as hot as required, but when idling at traffic lights or junctions the air immediately turns cold, but instantly turn hot again when the car moves off.
I don’t think its a thermostat problem as the car temperature gauge moves from cold to normal as usual. An air block somewhere would be what I’d suggest to someone, but I have service my own cars for many years and have changed coolant on many cars without issue, and even managed to keep air blocks out from the old Hillman Imps.
The other possibility that occurs is that its a physical block in the Heater Matrix - can these be flushed in situ?
I don’t know much about Mazda MX-5’s. Hopefully someone will be able to give abit of advice of how next to proceed.
TIA
Cheers Bob
The NC is a pain to bleed properly.
I always have the car facing up hill ( as steep as possible ) and I use a system bleeding funnel
This one - Spill Proof Radiator Coolant Filling Funnel Kit 15-pcs Cooling System fill kit | eBay UK
Im not looking forward to doing my thermostat replacement then… sounds like its a proper pita
Hillman Imp. Brilliant car in many many ways, and worthy of a mention in these pages!
TBH - use a filling funnel as above and have the car elevated at the front ( ramps or a hill ) and it can be bled reasonably well.
The manual has a process to assist bleeding
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Thank you guys very much for you multiple swift replies - much appreciated. Will order up the funnel kit as mentioned above and when the weather improves will follow suggestions, and report back as to their success or otherwise.
Again many thanks.
Cheers Bob
As been mentioned you just need to get the cars front end up (ramps) and bring the car up to operating temp, squeeze a few hose particularly the heater hoses. It should eventually release any trapped air. It’s a bit of a mystery why it heats up then goes cold though, points to a dodgy stat but it’s been changed??
When putting you hands in and around the engine bay be keep away from the moving belts pulleys, I gave those hoses a squeeze at the front without the engine running, it worked for me and my NC?
