Heater Matrix?

[another_clean_sheet]

I have just realised that my heater is only blowing out cold air irrespective of what temperature I set the temperature control to.
Is the problem likely to be a blocked up heater matrix and that I need to remove it and flush it through to clear out the gunge?
Thanks for any advice.

[dave lincs]

no heat at all? check coolant level first if no heat

[another_clean_sheet]

Originally Posted by dave lincs

no heat at all? check coolant level first if no heat

Hi Dave,
You are correct!! I have just added a fair bit of coolant. It was OK a month ago as I changed the thermostat in my on line thermostat (it is a diesel if you remember) and only had to top it up a little bit due to a small amount of fluid loss in doing the change.
The air is now warm (OBD coolant temp is 86 degrees C) though not hot. I do not know if there is still an air blockage (bleed nipple is OK) but I have got a 25 mile round trip to a bowls match this afternoon so see what happens.
Cannot see a leak. Have a gravel drive so would not notice any drips on the drive.
Many thanks.
Mike

[dave lincs]

Hi Mike

I would suspect the leak will be the o ring on the metal pipe where it goes into the thermostat housing on the side of the engine

Dave

[EastPete]

I think that removing/replacing the heater matrix is a bit of a bar steward of a job, to be avoided if at all possible. I had poor heater output and slow warm up in the cold weather, but flushed the system through with Holts speed flush and fitted a new 'proper' thermostat and o-ring and all is now well. I think there is a way of flushing the heater matrix in situ by putting a hose pipe into the inlet/output pipes on the bulkhead, but I have never taken the trouble to locate them or try this approach.

Pete

[another_clean_sheet]

Originally Posted by dave lincs

Hi Mike

I would suspect the leak will be the o ring on the metal pipe where it goes into the thermostat housing on the side of the engine

Dave

Hi Dave,
Back from bowls (won 18 - 15!!). Car was a lot warmer. However when I got in I had to put 1 1/2 pints in the rad. Not sure if it was due to leakage and/or clearance of an air blockage.
Shame Andy is not doing any work on 75s at the moment as I have a couple of other jobs that need doing. Also means you will not be able to share some home made fruitcake (without nuts) when I visit.
Mike

[SD1too]

Originally Posted by another_clean_sheet

However when I got in I had to put 1 1/2 pints in the rad.

Mike; if you haven't already done so, follow the official MGR procedure for refilling (after repair work) and bleeding.

Simon

[another_clean_sheet]

Originally Posted by SD1too

Mike; if you haven't already done so, follow the official MGR procedure for refilling (after repair work) and bleeding.

Simon

Filled it as per the procedure and have been running the car for 3 weeks with no apparent trouble. Not sure why I orginally had to top it up with a couple of pints unless I have had a large air blockage that cleared so the coolant level dropped in the header tank.
Thanks to you and Dave Lincs for the advice.
Mike

[SD1too]

Originally Posted by another_clean_sheet

Filled it as per the procedure and have been running the car for 3 weeks with no apparent trouble.

Thanks for the positive feedback Mike. Sometimes the solution can be cheap and simple!

Simon