Heater does not work, AIR CON Model

sagegreen

Member
Hello dear P6 professioals (Part 4)

I really need your help, because I run out of ideas and logic solutions
Well, my car (Rover 3500S NADA) has some little difficulties at the moment.

1.) No sound/crank from starter (I post in electric section)
2.) Horrible squealing brakes (I post in brake section)
3.) Hazard flasher switch not working (I post in electric section)
4.) Heater does not heat (I post in engine section)

Nr 4., AIR CON model, not heating anymore, or how „so called mechanics“ can ruin things.

2 years ago I had to look for a new garage which I can trust, so I brought my car to a garage (oldtimer cars) because the idiot of the Range Rover garage switched the tappets in wrong order, during changing the cylinder head gasket 3 years ago) He just said, this is no problem, the tapping of the tappets will disappear soon. Of course, It did not. My car is still tapping beyound 40 mph.

Well, the guy in the oldtimer cars garage also repaired a screw (worn, stuck) of the inlet manifold, changed the thermostat, but forgot to change the tappets (just cleaned it??!!! = another Story how stupid some People are)…..since then, the heater does not work anymore. Its an air-con model, so If I turn on the heater knob, I hear the water rustle, but the air stays cold.

So, last year, I brought the car to another specialist (because I lost trust in Oldtimer Garage after this**) , he was looking for the fault behind the centre console inside, behind electric window switches, the vaccum pipes, wires, etc…

My question: where I must start to look for this problem? Is it a simple thing like, a wrong or defect thermostat inside the inlet manifold? Defect heater matrix? Something with the water circuit? The AIR CON tater tap on the end of inlet manifold plus Water tap metal wire (to heater unit) looks good and is not broken.

I really appreciate your help and advices. Not only I run out of ideas, I run out of garages and mechanics here in Austria, because they all ruin more then help me.

(**another expensive example: they ruined my at BW 35 Transmission, it was repaired by ROVER CLUB Austria, but they did also not work good enough, because BW 35 is loosing much oil again) (this will be Part 5.....someday) :) :D

Thank you very very much
Richard
sagegreen
 

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Hi Richard,

The matrix within the heater can become blocked with sediment, hence flow of hot coolant through essentially stops, consequently the flow of hot air also stops. It could also be down to the insulation that had been applied to the air directon flaps having deteriorated. In both cases to be sure of the cure, the heater needs to come out.

A thermostat that is always open will also impede nice warm air from the heater to one degree or another. Where does your temperature gauge normally register?

Sorry to hear that you have had such a bad run with the paid help. Hope that will improve for you!

Ron.
 
sagegreen said:
Well, the guy in the oldtimer cars garage also repaired a screw (worn, stuck) of the inlet manifold, changed the thermostat, but forgot to change the tappets (just cleaned it??!!! = another Story how stupid some People are)…..since then, the heater does not work anymore. Its an air-con model, so If I turn on the heater knob, I hear the water rustle, but the air stays cold.

If indeed the problem appeared after changing the thermostat, without touching anything else on the heater, then it seems that there is an air lock that impedes the circulation of the water in the heater matrix.
I am sure there are older posts in the forum on how to get away from an airlock in V8s, have a search on the subject.
There is also an easy way to confirm it. With the engine running at normal temperature, the hoses that connect to the heater should be hot. On non A/C heaters, the water circulation through the heater matrix is permanent, no matter what the heater settings inside the car. Since you have the A/C heater box, you should also have a water tap somewhere, so make sure that it opens when the settings inside the car are on hot.

If you have a circulation of hot water into the heater matrix, but not hot air into the car, then it gets more complicated, but at the moment try to eliminate the simpler things.
 
SydneyRoverP6B said:
Hi Richard,

The matrix within the heater can become blocked with sediment, hence flow of hot coolant through essentially stops, consequently the flow of hot air also stops. It could also be down to the insulation that had been applied to the air directon flaps having deteriorated. In both cases to be sure of the cure, the heater needs to come out.

A thermostat that is always open will also impede nice warm air from the heater to one degree or another. Where does your temperature gauge normally register?

Sorry to hear that you have had such a bad run with the paid help. Hope that will improve for you!

Ron.
Hello Ron, thank you for response.
This is good to hear that (maybe) an always open thermostat could be (if I have luck) the reason..I order a 82 degree thermostat now, maybe the other (fitted by garage) thermostat is a wrong one, because - as you told this now - I am wondering, why I did not heard the “click clap” of the opening thermostat so long time anymore. Maybe it’s a wrong one and was always open…well, this helps me a lot and give me hope, to let the heater unit still in the car….hahaha…

Temp gauge: well, as far as I remember in the middle of the green bar (85 degree), after circa 90 degree the electric fans start to cool. The only thing which happened more and more was, that after stopping the car to park, the radiator overflow pipes spits hot water.
(RON): Sorry to hear that you have had such a bad run with the paid help. Hope that will improve for you!

Yes….its painful with most garages here (because the old mechanics from British Leyland Austria days are all retired or dead) and nearly all “difficulties” on my car are created by the mechanics of today.

Thank you very much, Richard
 
Demetris said:
sagegreen said:
Well, the guy in the oldtimer cars garage also repaired a screw (worn, stuck) of the inlet manifold, changed the thermostat, but forgot to change the tappets (just cleaned it??!!! = another Story how stupid some People are)…..since then, the heater does not work anymore. Its an air-con model, so If I turn on the heater knob, I hear the water rustle, but the air stays cold.

If indeed the problem appeared after changing the thermostat, without touching anything else on the heater, then it seems that there is an air lock that impedes the circulation of the water in the heater matrix.
I am sure there are older posts in the forum on how to get away from an airlock in V8s, have a search on the subject.
There is also an easy way to confirm it. With the engine running at normal temperature, the hoses that connect to the heater should be hot. On non A/C heaters, the water circulation through the heater matrix is permanent, no matter what the heater settings inside the car. Since you have the A/C heater box, you should also have a water tap somewhere, so make sure that it opens when the settings inside the car are on hot.

If you have a circulation of hot water into the heater matrix, but not hot air into the car, then it gets more complicated, but at the moment try to eliminate the simpler things.

Hallo Demetris, :D
thanks for advice to older posts (airlocks). I will search
Hot hoses: good idea, as soon my starter works again I will check this.

yes, it appeared since the mechanic took off the inlet manifold, disconnected all water hoses, changed the thermostat.
I told the guy, my heater is not working: he said: he forgot to bleed (vent) the heater.
So, I vent (bleed) the heater, but nothing changend (I did it like described for Air Con models in the 1969 Rover repair manual)

Thank you very much, Richard
 
Did this ever get solved?

I have had heater failure twice on my NADA. Once because the vacuum pipe from the manifold to the Ranco valve came off, meaning that no hot water flows to the heater matrix regardless of dial position, and once because the Ranco valve failed (vacuum diaphragm vailure I suspect) and the same thing happend. Except this time when I turned the heater on, all the hot water ended up on the garage floor!
 
The NADA models have a very complex thermostatically-controlled heating system that involves a vacuum-operated water valve that also senses the core temperature to regulate water flow. I imagine the design life of this unit was about ten years. Do the math. I would first thing check for opening of this valve (# 606627 in the parts manual) when you turn the heat on. You might just replace it with a hand-operated valve to be opened in the fall and closed in the spring. I replaced mine with an aftermarket valve (for some kind of Ford) that at least opens and closes with vacuum control, but it does not have the thermostatic control.

gbvona
 
Take a gander at the unit behind the heater control. Lots of vacuum pipes, one with 3 way splitter .Might have come adrift at that point or like mine -broken
 
The NADA models have a very complex thermostatically-controlled heating system that involves a vacuum-operated water valve that also senses the core temperature to regulate water flow. I imagine the design life of this unit was about ten years.
gbvona

Hello gbvona, thank you for your important response.
is it the RANCO VALVE?

Kind regards and thank you
sagegreen
richard
 
Take a gander at the unit behind the heater control. Lots of vacuum pipes, one with 3 way splitter .Might have come adrift at that point or like mine -broken

Hi GRTV8, thank you for the info - I will check it. You mean those black rubber pipes?
thank you and Kind regards
 
The Duchess has retro fitted aircon from a NADA. In order to work properly all the vacuum motors have been replaced and to get temperature control another vacuum operated valve is used to divert/moderate hot water flow into the matrix. This has a completely separate and resited control. The coolant circuit has largely been replaced with new or refurbed parts. The only irreplaceable essential bits are the coolant and heater matrices and the vacuum control switches. The latter control the direction of the vacuum feed to control air flow to the cabin/screen. Everything else can be replaced/jury rigged to work. The biggest weaknesses are the poor airflow even from a new motor, I suspect because it is hard to ensure complete sealing of the airways. It is good to get hot air in the winter and cold air in the summer, even if it is nowhere near as good as modern systems. What can be expected after 50 years! The secret is to find somebody who understands aircon systems and is able to develop work arounds.
 
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