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Hi all,

1984 Spider S3, Engine heats up fine and keeps constant temp but no hot air inside. I have changed the theromstat. If I squeeze the hoses to and from heater the water rises and falls in the top of the radiator so I presume there is no blockage. Or maybe an air lock, if so how do I remover the air? The heat slider control in central console doesn't seem very stiff, is it possible it has come adrift? I have put my hand up under the dash by the heater but can't feel any valve opening/closing. Where is the valve and can I check it without removing heater. Car is a converted left to right hand.

Thanks in advance.

Patrick
 

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you need to get on your back on the driver's side (that'll be the left side, so passenger side on your rhd conversion;)) and look up at the heater valve.......if (as you say) you feel no resistance at all with the heater slide, it is just possible the solid rod has come loose at the clamping bolt.........failing that then the heater valve is most likely the cause and needs to be replaced.

It can 'just about' be done by lying flat on your back in the footwell (remove seat, get on your back with a small head-light/torch.......) it is a pain, not terribly difficult but takes time and you will swear a lot!

photos here show location, it is an earlier valve (with a bleed screw on the valve itself, which yours prob. doesn't have) but mostly identical.
http://www.alfabb.com/bb/forums/5242282-post1.html
 

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I had the same issue this spring and a very simple fix ... top up the coolant and replacing the rad cap to ensure the system maintains pressure did the trick!
 

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Over the 20 years of owning my Spider I have had this issue twice - the first time was a faulty heater valve as suggested above; the second time (very recently) it was a blockage on the small pipe going in (or from) the water pump. I removed the heater hose from the water pump and no water drained out of the pump just a little from the hose. I prodded the water pump outlet with a screwdriver clearing the blockage and the coolant poured out. The orifice is quiet small. I mention this as checking for a faulty heater valve is more involved than checking the water pump inlet/outlet for the heater.
 

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I had this problem once. Heat worked one winter - never turned it to heat for 9 months - and when I finally did the following winter. No heat.

Blockage? Swollen rubber heater valve?

Blowing either way with a spray nozzle on a hose did nothing to loosen up potential blockage. Some have said don't try this method unless as a last resort as if may blow something and you will then HAVE to get to the heater valve and hoses.

What I eventually did was flush the coolant, blow the hoses, set it to hot and just drive around through the winter with no heat.

And lo, in the spring, the heat came back. Shrugs.

So - just leave the heat open and drive around. Not saying it will work. But I'd rather be cold on a cruise than tear apart my non-main car. Now if it's your daily transport...hmmm. I'd still just freeze. ;) but you could turn it to hear and leave it there for a
Month. If something is blocking the force of constant hot coolant may break it free.
 

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I would drain the cooling system, then proceed to give both the radiator and the heater matrix a good backflush, to get all the crud out, and to ensure the circuit through both coils was clear of obstructions. Tick that box. I would then have a look at the heater valve, while flushing the heater core. If the valve was manipulated while water was flowing through the coil, you could determine if it was opening and closing/blocking flow correctly - this would eliminate the inner workings of the valve itself. Next thing I would check would be the controls - correctly connected up ? Giving the valve full opening 'stroke' when the slider control is operated ( Only one controls temp - the other controls the direction of airflow through the coil only.) If all of the above check out, the thermostat would come into question. Might be worth opening the housing, taking out the stat, boiling it, and with a meat or similar thermometer, watch the water temp and the stat itself to see if / when it opens as it is heated. Once all those checks are completed, the only remaining variables would be the water passages through the engine block, the function of the radiator cap (ensuring the system maintains pressure), and the hoses connecting everything together...are these clear and flowing freely ? If all of the above prove OK, you should be getting heat !!
Make sure you bleed the system completely when you refill it, to avoid any airlocks. Plenty of threads here on the BB about that.
Did the car exhibit any overheating or similar issues in the summer ?
 

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Discussion Starter #8
blowing hot then cold now.

Thanks for all the advice. I have found the valve and it seems to be opening and closing ok. I have drained everything and refilled. I have recently replaced the thermostat so I can't think this would be faulty. Still no heat until today! Started car up and ran for a while stopped and left for 10 minutes started car again and drove off, within a few minutes the heater was blowing out lovely hot air. Gradually hot air was replaced by cold air! Now I'm really puzzled, is this a sympton of an air lock? If so how do I overcome it.
Thanks in advance
Patrick
 

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My no heat issue ended up being a problem in the heater box itself. The flap that controls the airflow through the core was positioned wrong, and wasn't letting the air flow through the core.
Do you have a full throw on your hot/cold lever?
 

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First cold weather of the season here (60's, I know..don't laugh..I'm a Floridian..). Heat came out of the top (dash) vents but nothing out of the front vents. Levers seem to be working fine. Heat comes out the floor vents too. Just nothing out of the front vents....ugghh...another thing for the to do list....
 

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Spider heaters don't direct hot air out the front vents.
Well, thank you for that insight! I would have spent the better part of my morning tryng to figure that out!

If I recall correctly, the manual devotes a whole page to "vent controls".....I'm going to go back and reread that section. I didn't think it would be that complicated......and, I guess it wasn't!
 

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I suspect you're back at checking/replacing the heater inlet valve. When the rubber diaphragm inside fails, moving the console lever & seeing the valve's external arm moving does not mean the valve has really opened - so hot coolant never goes through the heater core.
 

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I recently had no heat. Turns out the thermostat was not closing all the way.
 

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Discussion Starter #19
Hi al,
Finally got around to sorting out my heater. I changed the valve on the heater and now have lots of hot air. Job took one hour and not as difficult as expected. Would recommend trying this if your heater doesn't work.
 
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