Odd coolant behaviour

[iani]

Update: I brought the car home on Thursday, the temp gauge sat at the half way point all the way home but still no heating. Today I drained the coolant, blew through the coolant pipes and was going to remove the block drain plug but was surprised to find that it was still the original tap, I opened it and it flowed well. I put some Barrs flush in, filled with water and then took the car for a drive, after running the engine for around 90 mins I drained the system again, very rusty water came through, flushed through until it ran clear from all orifices. I am pleased to say that I now have a heater, it's rubbish but it is working, thanks for all the comments.

[thescrapman]

Next thing to do is pop the heater out and fit new furry / foamy seals.

make sure what meagre air flow is going the right places.

[standardthread]

17 hours ago, iani said:

I am pleased to say that I now have a heater, it's rubbish but it is working

They are supposed to be 3kw plus, depending on physical core size but they are all rubbish, from the Standards through to the Dolomites.

[RobPearce]

1 hour ago, standardthread said:

they are all rubbish, from the Standards through to the Dolomites.

I always found my Dolomites to have excellent heaters. Better than the big saloons, although they weren't bad. The Herald/Vitesse/Spitfire/GT6 heaters were a waste of space, though.

[glang]

For the earlier cars this is not a surprise as with the heater valve closed the coolant flows through the manifold and back to the pump suction. Then opening the heater valve doesnt close that circuit but just opens a parallel one so the coolant, if it feels like it, can also flow through the heater😯 

For improved heating it would probably be worth trying to block this valve bypass route so that ALL the coolant to the manifold also goes through the heater (as is the case in more modern vehicles). The only down side would be that if the heater valve is closed on a cold start the pump will have no flow path as the engine thermostat will also be closed plus of course there will be no warming of the manifold to reduce the time the choke is needed....

[Tim Bancroft]

Must agree, MK1 2000s have rubbish heaters...Mk2 seem positively pleasant in comparison!

GT6...not sure it is necessary apart from using the demister.....!

[glang]

yes it was a big step forward when manufacturers went for heaters with coolant flowing constantly and controlling the air flow rather than as previously varying the coolant flow!

[standardthread]

4 hours ago, glang said:

For improved heating it would probably be worth trying to block this valve bypass route so that ALL the coolant to the manifold also goes through the heater (as is the case in more modern vehicles). The only down side would be that if the heater valve is closed on a cold start the pump will have no flow path as the engine thermostat will also be closed plus of course there will be no warming of the manifold to reduce the time the choke is needed....

One solution/improvement, block the bypass AND adjust the cable to the heater valve so that the valve can't be completely closed?

[glang]

Not sure if dead heading the pump is a problem as I have put a valve in the rubber hose from the pump housing to the manifold in my Vitesse and not had any problems on cold starts with it closed. I run like this when touring in summer in Spain to ensure the maximum amount of coolant goes through the engine/radiator rather than the manifold/heater...