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Vitesse mk2 heater blowing cold


Robin

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I don’t often use the heater and last time I checked the fan was blowing warm air into the footwell. I tried in recently and found it’s now only blowing cool air. The car is coming up to temperature as normal and the top and bottom radiator hoses are warm but the hose from the thermostat housing to the manifold and the hoses connecting the heater valve to the heater matrix are cold (but water is flowing ok). Would this suggest a faulty thermostat or do I need to look elsewhere for the problem? 

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If the engine is not coming up to temperature, try a thermostat change first.

If the engine is coming up to temperature on the gauge and the cooling system is full.....

- the heater valve may appear to operate without actually allowing much flow have clogged up or fallen apart inside

- heater matrix may be clogged. Can be flushed in situ.

- if the valve and matrix are both passing reasonable flow, it’s possible that the internal divider in the heater matrix has failed allowing most of the flow to go direct from inlet to outlet.

Nick

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Hi Nick

engine is coming up to temperature according to gauge and cooling system is full. What’s confusing me is the hose from the thermostat housing to the manifold and the hose from the manifold to the heater valve is cold - shouldn’t this have warm water running through?

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Pipes to the heater will be cold for most of their length if the heater is off, or if the valve is stuck or blocked. Easiest way to check is to disconnect the valve and run a pipe straight to the heater, this will tell you if the heater is working ok. You can clean the valve - in fact you can clean the heater too - by disconnecting the heater pipes and flushing them in both directions using a hose, making sure the valve is open, but it's also easy enough to take the valve off and clean it, even poking a short length of wire through it can clear debris. 

One other small point - are you sure the valve is opening and closing, and it's not just the dashboard control moving about but doing nothing? It's happened to me before, so check if you can see the valve physically opening or closing. Is it a Smiths or Delaney Gallay heater?

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It may be the water heated inlet manifold blocked as this feeds the heater. Do not try to undo the large nut at the heater end of the manifold as it will break off. Clean out it's ports with a piece of stiff wire, plus flush through with water

Dave

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4 minutes ago, Colin Lindsay said:

Pipes to the heater will be cold for most of their length if the heater is off, or if the valve is stuck or blocked. Easiest way to check is to disconnect the valve and run a pipe straight to the heater, this will tell you if the heater is working ok. You can clean the valve - in fact you can clean the heater too - by disconnecting the heater pipes and flushing them in both directions using a hose, making sure the valve is open, but it's also easy enough to take the valve off and clean it, even poking a short length of wire through it can clear debris. 

One other small point - are you sure the valve is opening and closing, and it's not just the dashboard control moving about but doing nothing? It's happened to me before, so check if you can see the valve physically opening or closing. Is it a Smiths or Delaney Gallay heater?

Hi Colin

I did take the heater matrix out and gave it a quick flush with a hose and it seemed to be ok. The heater valve also moves freely and is working from the dash pull knob. It’s a Smiths heater. Will try and connect the hoses directly to the matrix. So is the thermostat an unlikely cause?

 

 

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8 minutes ago, dave.vitesse said:

It may be the water heated inlet manifold blocked as this feeds the heater. Do not try to undo the large nut at the heater end of the manifold as it will break off. Clean out it's ports with a piece of stiff wire, plus flush through with water

Dave

Hi Dave - ok will try this if all else fails

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if your gauge is reading about normal then its unlikely the stat is in trouble assuming from cold  that   a warm up didnt take all morning .

if its failed then all runs cool , its always worth a check if you have her drained down to check all the other ideas 

Pete

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Another vote for flushing through with a hose. when I sorted mine out it was the valve that was completed blocked so replaced it.

Flushing through in both directions cleared out a lot of brown water, once clean comes out connect everything up again and top up the cooling system (you are bound to lose some during the dismanteling) with the heater valve in the open position.

The fact you had hot air a while ago might just be a false lead. Mine did that so I thought it had started to work again on its own but it was simply due to the build up of warm air in the unit being blown into the car.

It is worth doing as the heater does make a difference, even in my convertible with the hood down. 🌋

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As Doug suggested earlier I took the hose off the inlet manifold to see if there was a blockage. I used an old metal coat hanger but it only goes about half way along the inlet manifold before it stops and doesn’t want to go any further even with some pressure. Any advice on how to remove the blockage ? I ‘m assuming i need to take the manifold off and use a stronger rod to move anything that’s blocking the water flow?

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Hello Robin,

I would measure how far you can get the coat hanger in to the manifold from each end - that will give you a rough idea as to how thick the obstruction is. If the distance is slight you should be able to break through it with aggressive prodding. If a lot thicker then it will take more work; I'm just trying to save you taking the manifold off initially if you can deal with the blockage in situ.  

Something more stout than a coat hanger would be useful - do have a long thin drill bit or similar ??

When you do sort it out, as I am sure you will, may I suggest using a 50/50AF coolant mixture which goes some way to stop scaling etc if you do not already do that.

Regards.

Richard.

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13 minutes ago, classiclife said:

Hello Robin,

I would measure how far you can get the coat hanger in to the manifold from each end - that will give you a rough idea as to how thick the obstruction is. If the distance is slight you should be able to break through it with aggressive prodding. If a lot thicker then it will take more work; I'm just trying to save you taking the manifold off initially if you can deal with the blockage in situ.  

Something more stout than a coat hanger would be useful - do have a long thin drill bit or similar ??

When you do sort it out, as I am sure you will, may I suggest using a 50/50AF coolant mixture which goes some way to stop scaling etc if you do not already do that.

Regards.

Richard.

Hi Richard - I can get the coat hanger about half way from the thermostat end. The heater end is trickier because of the angle needed to get the wire into the manifold - needs to be bendy but strong. Will see if I can find a piece of pipe to attack from the thermostat end but the blockage seems pretty solid so god knows what it is.

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Normally it all back-up along the pipe, the main cause is a block on the heater end. Try blanking off all but one of the pipes at the heater end. Then feed water in the one remaining pipe, heater end, whilst using the stiff wire the thermostat end.

Dave

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If it's well blocked, get hold of a very long masonry drill - as that's the type that are readily available in 14" length - somewhat smaller than the bore you want. Slide a couple of bits of tube (plastic, rubber or steel, whichever comes to hand) over it. Ideally you want something with a bore just big enough for the drill and an OD just smaller than the pipe bore. Alternatively, you could wrap a couple of loops of masking tape, layered thickly enough to fit cleanly in the pipe. Then when you insert this drill down one end of the pipe, the bits of tube will hold it central so that you're drilling through the crud, not the side of the pipe. Once you've drilled through the middle it'll be a lot easier to clean out to the edges. Use a slow drill so as not to melt your guide tubes.

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Ok - I’m going to try and unblock the inlet manifold but two quick questions:

1. I’m assuming that because the manifold is blocked and no water is flowing through it then this will cause the loss of heat from the heater?

2. if I can’t clear the blockage will it cause any damage by still running the car?

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Morning Robin,

1- it certainly will not assist and yes it is more than likely to reduce / stop the heat output. I presume the heater matrix is okay but if compared with the manifold it is likely to be clogged as well - have attached a photo of how bad they can get albeit from another marque.

2- no it should be fine but the coolant system will not be operating at max benefit.

Regards.

Richard.

DSC00180.JPG

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32 minutes ago, Robin said:

Ok - I’m going to try and unblock the inlet manifold but two quick questions:

1. I’m assuming that because the manifold is blocked and no water is flowing through it then this will cause the loss of heat from the heater?

2. if I can’t clear the blockage will it cause any damage by still running the car?

No - or rather it shouldn't if the pipe is solely to the heater. Just keep an eye on the gauge and see if it's behaving.

I don't know the Vitesse layout but it must be possible to run a parallel pipe to the heater, bypassing the manifold pipe, to see if it's working?

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6 minutes ago, classiclife said:

Morning Robin,

1- it certainly will not assist and yes it is more than likely to reduce / stop the heat output. I presume the heater matrix is okay but if compared with the manifold it is likely to be clogged as well - have attached a photo of how bad they can get albeit from another marque.

2- no it should be fine but the coolant system will not be operating at max benefit.

Regards.

Richard.

DSC00180.JPG

Thanks Richard

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7 minutes ago, Colin Lindsay said:

No - or rather it shouldn't if the pipe is solely to the heater. Just keep an eye on the gauge and see if it's behaving.

I don't know the Vitesse layout but it must be possible to run a parallel pipe to the heater, bypassing the manifold pipe, to see if it's working?

Hi Colin - yes I can bypass the inlet manifold but I’m curious to know what function the water flow through the manifold performs?

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Just now, Robin said:

I’m curious to know what function the water flow through the manifold performs?

The idea of warm / hot water passing through the manifold is to assist quicker operating temperature of the air / fuel mixture and reduce the amount of time the choke was required. That is certainly my understanding, but a more scientific answer will hopefully come along.

Regards.

Richard.

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The heater/manifold has nothing to do with the thermostat as water is flowing the whole time before the thermostat opens. This allows the manifold to be heated as soon as the engine starts to warm up meaning you can push the choke it earlier...

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