Heater not working

Started by Jared, August 26, 2023, 18:18

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Hi all
Just had my first MR2 ever and I have to say it's fantastic, had a Porsche before this and this thing is better for out right fun hands down.
I think all is well apart from a few little things but first thing I did this morning was put the heater on but it doesn't get warm.
I have AC and that is working great and the fan speed works as it should just no heat.
Is this a common thing with a quick fix or am I looking at something more of a problem.
Cheers all

Chilli Girl

Welcome by the way.  MR2 heaters are excellent so I'm very surprised you don't have any heat.  What I will say is this - make sure you have the vents open as I had mine closed and felt abit of an idiot.  Hopefully this isn't the case with you. ;)
Ex owners of Chilli red facelift 52 reg called Chilli, silver 55 reg called Foxy and blue pfl W reg MR-S called Sapphire. Now 2 less!


You might need to bleed your coolant system. Sometimes it is a trapped bubble in the heater core.
If you do a search you will see what is required to bleed the coolant of any air pockets.


as the above 2 posts.
The MR2  heater is excellent. A bit too much in fact.
As above, likely an air lock.


 :) that is a 1st for sure about lack of heating :o  :o
defo a problem there that needs looking at at :o

the above post are good starter points 8)  8)



As above, the heater is a toaster, so something amiss with yours.
If you have had a look around under the frunk plastics you may have noticed two coils of plastic tubing, these are there to increase the " head" of the coolant when bleeding the heater. If these lengths of tubing aren't available you would do well to get some. Last time I looked B&Q sold tubing from a reel that you cut off yourself. Mine are two 750mm lengths of 9mm x 7mm tube.
Mine were tied up to valves on the heater hoses that are also under the frunk plastics.
Bleeding is a matter of getting the engine up to temperature, putting the heater control to full on, finding some string, fitting your two tubes to the heater tube valves and using the string tie the tubing up under the bonnet. There is likely a " best" sequence for opening and closing the valves, but iirc it is no more difficult than bleeding a central heating radiator.



Well worth getting comfy and hitting the search.

Few posts I recall, the bleeding can go sweet, it can be a git.

And I recall some the air bubble was something in or around the throttle body area.
As above, should be toasty.

I think some vouch for getting the rear end, high as well.


Cheers all, yes probably an air bubble somewhere in the system, although I did get some heat going to work the other morning so I'm sure it's not a big deal but needs to get sorted before winter


I would not want to leave it too long in case an air lock would hinder the coolant flow around the engine.
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Quote from: Jared on September 12, 2023, 15:21Cheers all, yes probably an air bubble somewhere in the system, although I did get some heat going to work the other morning so I'm sure it's not a big deal but needs to get sorted before winter
Yep, get that sorted and you will be toasty.


I have noticed something similar, and also suspecting air in coolant issue.

I only get hot air from side vents. I don't get hot air now from middle or footwell.

I occasionally hear a liquidy gurgling sound for a few seconds after a cold start coming from the HVAC area near the front.

Coolant bleed a good idea?
2004 MR2 Roadster Sable/Red<br />2005 Corsa 1.2<br />2003 E46 M3 Coupe SMG


I've recently had this with my 2zz and it was a stuck closed coolant thermostat. This is very dangerous as the temp gauge only read a couple of notches above middle/normal even though temps were 120°c using torque pro. If left to go much higher the head gasket would have gone.