luke warm heating

This section is for technical Q & A
Please try the search function before starting a new thread.
Forum rules
Many subjects will have been discussed before. Please try the search function before starting a new thread.
Check in the Know Your 2 as the information you need may already be there.
Important ! - Please make your topic title as descriptive as possible . titles with just "help" generally dont get as many answers as a title that points to the problem
The forum Administrator has chosen to advise you that this topic is 4 years and 3 months old and that you may wish to begin a new topic or use the search feature to find a similar but newer topic.

Topic author
harri46
Posts: 93
Joined: 03/07/13 20:59

luke warm heating

Post by harri46 »

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


User avatar

SonicSW20
Posts: 2858
Joined: 29/11/10 19:50
Years of MR2 Ownership: 10
MR2's Owned: 3
Location: UK
Been thanked: 6 times

Re: luke warm heating

Post by SonicSW20 »

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?
Rev5 Sonic Shadow
Image

Topic author
harri46
Posts: 93
Joined: 03/07/13 20:59

Re: luke warm heating

Post by harri46 »

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?
User avatar

peteV6R5
Posts: 2683
Joined: 13/08/07 13:06
Years of MR2 Ownership: 12
MR2's Owned: 2
Real Name: Pete
Gender: Male
Location: Stratford upon Avon
Has thanked: 2 times
Been thanked: 11 times

Re: luke warm heating

Post by peteV6R5 »

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
Image
Highland Drive 13/14/15/17/18/19
JAE 07/09/10/11/12/13/14/15/16/17
Japfest 09/11/12/13/16/19
Wales runs 14/15/16/17/18
User avatar

jimi
Administrator
Administrator
Posts: 5164
Joined: 17/05/04 1:00
Years of MR2 Ownership: 18
MR2's Owned: 1
Gender: Male
Location: Glenrothes: The Kingdom of Fife
Has thanked: 45 times
Been thanked: 116 times
Contact:

Re: luke warm heating

Post by jimi »

https://www.mr2oc.co.uk/know-your-2.htm ... bartid=161
This KY2 article covers bleeding the cooling system, from about section 25 onwards ;)
Black is not a colour ! .... Its the absence of colour
Image

Topic author
harri46
Posts: 93
Joined: 03/07/13 20:59

Re: luke warm heating

Post by harri46 »

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

Quick Reply

   
The forum Administrator has chosen to advise you that this topic is 4 years and 3 months old and that you may wish to begin a new topic or use the search feature to find a similar but newer topic.

Return to “MK2”