MR2 Owners Club

Hi All.

I have a mk2 1991, and have been having problems with the heater on the car for a while. Heater blows 'lukewarm air' and as you get to the third and fourth fan speed's it becomes virtually cold. I have a new radiator, waterpump, and have changed the radiator cap. Have been advised it might be the thermostat, but there isnt much movement in the temp guage ranging from half way up to about quarter of an inch lower so not sure about that.

There's no leaks, and the radiator is topped up.I had it running with the radiator off to get rid of any air in the
system which has improved it slightly, but its still not right.

Be grateful for any advice.

Darren

Have you confirmed that sliding the heat control is actually fully adjusting the valve? Have you also confirmed that you actually have flow through the matrix?

Does the car get up to operating temperature (middle of the gauge or just below) and stay there with little deviation?

Hi.

Wouldnt know how to test the heat control/valve or the flow through the matrix.
Once up to operating temperature, the gauge stays about half way or goes down about quarter of inch below.

Is that deviation enough to require a new thermostat?

deviation sounds like you have air in the system

did you bleed with heater open fully

also there is a bleed screw on the heater inlet in frunk

https://www.mr2oc.co.uk/know-your-2.htm ... bartid=161
This KY2 article covers bleeding the cooling system, from about section 25 onwards

Thanks for the replies and info. Looks like a new thermostat aint gonna fix it then. Will look into getting air out of the system.

Cheers

Darren