NC Thermostat ? no heat from heater

  1. My model of MX-5 is: _mk3 _
  2. I’m based near: __Stockport
  3. I’m looking for technical help or recommendations on: __the above

Hi All went for spin roof down, then put heater on but its warm not hot ?? Last week while out temp gauge went very hi then was up a down for while then back to norm ? any ideas im thinking thermostat

Temp gauge shouldn’t move once up to just below halfway on the gauge. Lack of real heat in the cabin is a sure sign the stat needs changing.
If the coolant hasn’t been changed and the car is around 10-11 years old change that too.

advice given to me was to get one of those bluetooth OBD code readers that tell you the actual temp and not rely just on the gauge. Think it cost about £10 from eBay. Found that the car was running at approx75 - 80 degrees which was too cool. So I changed the 'stat. No where near as scary as some would have you believe, took about 2 hours of slow work including full coolant refresh.

Nice hot heater now.

1 Like

Thanks guys car had new rad when I bought it just over a year ago so had fresh coolant then

Thermostat is the obvious thing,

However, another faint possibility…
There was a mod applied to the later NCs in the shape of a U-bend added to the small hose to the header tank nearest the battery. This prevented awkward airlocks happening in the heater circuit.

Here’s a pic of the U-bend on my 2008 NC. (Header tank with fill-level sight glass is a Davefab ali.)