Old-style heater help

[Pierson]

My heater is the older, flat black box (non-fresh air) style 'driven' by a Crossflow. As I've not had heat for some while I decided to remove the valve and overhaul it in case it was stuck. In fact, the outlet was rammed solid with gunk which was clearly preventing water flowing back into the block.

 

Having trawled the archives I assume that the forward heater hose delivers hot water from the block to the heater matrix (inlet is on the bottom right of the heater as you sit in the car), passes over the matrix and then presumably exits on the left, through the valve and back into the block on the RHS of the engine close to the carb inlet manifold - is this right?

 

I've not experienced any cooling/overheating issues, the thermonstat cuts in when necessary and then out again once the temperature drops - but I'm curious if a blocked heater water circulation system could have done any form of damage. Having cleaned everything up the valve now seems to be working and the hoses are getting warm, so I'm assuming I have full circulation once again and I've topped up the coolant. Hopefully the open (i.e not sealed) nature of the Crossflow's plumbing will help or even eradicate any air which may have entered the system - though the hose flowing back to the block which was previously connected to the gunked-up valve outlet didn't have coolant in it anyway...

 

Please: no 'ditch the heater' advice, I want to keep it - just interested/concerned that the blockage may have damaged.... something?

 

Thanks for any advice,

 

Pierson

[ECR]

If your system had been perfectly clear and you then switched the heater off, you would be creating exactly the same conditions that your blockage caused.

No problems there ....

[Pierson]

Thanks Roger - that's what I had assumed but your confirmation is comforting!

 

Pierson

[Ian Macquarie]

I think the flow is in the oposite direction to how you describe it - out of the block at the inlet manifold and back to the engine just prior to the water pump.

Agree with ECR unlikely to have caused a problem.

You may find that water level keeps dropping for a while until air is all expelled from the heater - the design is not good from an air lock point of view.

Ian

[Pierson]

Thanks Ian - your articulation makes sense, although I'm a little confused in that I had thought that the valve would have been there to shut off the flow to the matrix by stopping it from entering the heater in the first instance. In the set up I'm observing it seems that the hot water enters the heater directly and the valve is only there to stop the flow, i.e. water can enter but not leave. Is this correct?

 

Pierson