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Interior - Heater for S1 coupé
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Q: Can anyone explain how the heater controls on my RHD 1968 1300 S1 rallye should work. I appear to have a red knob, a blue knob, a lever under the dash and a fan switch on the dash. The valve under the bonnet, just in front of the bulkhead gets hot, so I assume heated water is getting to the matrix, but the only control that seems to do anything is the fan and all it seems to do is make a dreadful noise!

A:To operate the heater you should first pull the lever to you, then turn the red knob anticlockwise and then the blue one in the same direction. For maximal efficiency the red as well as the blue knobs must be in the fully open position. The electric fan is normally quite weak and you should not expect any robust air flow through it. The various cables and linkages of the two knobs and lever are notoriously prone to malfunction. You should check that each one of them is working independently and, if it is not, you must adjust the cable, oil the control system, etc. Check in particular that there is a full operation of the heater valve which could be stuck. Even in the best conditions the S1 heating system is not very good and certainly less efficient than the S2 system. However, if the heater output (with all linkages correctly set) is minimal, then you have a blocked heater matrix which has to be renewed. It is a hard job to get it out of the car.
- Andrea -

Section below added august 2000 by me (Huib) based on my experience with heaters on several S1 cars.

The functions of the controls on S1 heaters are as follows:

Blue control knob (common to all S1 models)
Controls the total amount of airflow getting into the car.
Through a Bowden cable it controls a flap which is at the bottom of the tray under the airscoop under the bonnet on a coupé or in the air intake just behind the grille on a berlina. Turning the knob anti-clockwise puts the flap in the open position. Turning clockwise brings the flap to the closed position. Check its operation and if necessary adjust the cables.
Red control knob (common to all S1 models)
Controls temperature of air, if heater cock is open.
Clockwise = coldest
Anti clockwise = hottest
Through a Bowden cable it controls a flap inside the heater unit which controls the amount of air going through the heater matrix (thus the amount of hot air) and the flow around the heater matrix.
Put this knob slightly anti clockwise of the centre position with the heater cock closed if you want maximum fresh air on a hot day.
Heater cock control lever (common to all S1 models)
On the cars I have seen so far (all LHD cars) this lever is on the left of the heater control panel on coupé's and on the right on berlina's.
Pulling this lever opens the heater cock. Now you can regulate the temperature with the red knob.
Pushing this lever closes the heater cock. With the heater cock closed the air coming in is always fresh, whatever the position of the red knob.
Through a Bowden cable this lever controls the heater cock, which is under the bonnet. If not used for a long time it may be very heavy to operate. Use WD40 or something similar on both the lever part and the cock part.
Direction lever. Only on the later S1 coupé's and Zagato's.
It is under the panel with the red and blue knob.
Through a metal rod it operates connected flaps at the top and the bottom of the heater unit.
When in the up position air goes to the windshield and the vents at the sides of the dashboard. When in the down position air goes to the feet. In between air is divided proportionally.
On heater versions where this handle is not present, air will always go to the windshield and the side vents in the dash. On the heater itself you may find (stick your head under the dash) a flap running the width of the unit or two individual flaps on each side of the unit to control the flow to the feet. If you are a male driver and the passenger is a female and not your wife or girlfriend, you should inform her before operating the flap on her side to avoid getting a hit on the head as this may result in loosing control and thus the loss of one of our beloved Fulvia's.

Both on berlina's and coupé's as well as Zagato's the heater can be made to operate satisfactory, even at temperatures much below zero °C. Ventilation on a hot day is reasonable in a berlina (at speed), but lousy in a coupé. In a coupé one has to open the side windows.

Several things must be remembered in dealing with the heating systems of these sixties cars. I am giving a list of things from memory. It is not meant to be a scientific representation. It is to remind you that the world was somewhat different in the sixties. So, don't shoot me if I forget something or mix things up. Here in the Netherlands quite a few young people buy a Fulvia. Some even buy a Fulvia as their first (and only) car. Excellent. Good for these people and for the Fulvia's. But some have no idea that the world was a bit different 35 years ago.

  1. In those days it was normal to use water in the summer and water with antifreeze in the winter instead of coolant. I used coolant even in the sixties, but here in Breda, a city of over 100.000 inhabitants then, there was only one place to get decent coolant.
    It means there will be a lot of calcium and other deposits in the heater matrix (and other parts of the system). Also plenty of rust. Modern coolants have rust inhibitors and no calcium. Not so the water with antifreeze.
    Also the cooling systems were not "closed systems". Water evaporated and disappeared through the cap, leaving calcium and other minerals. Fresh water (with more minerals) had to be added frequently. In many parts of Europe tap water was not even drinkable because of the heavy contamination.
  2. Electrical items such as fans and dynamo's were much less powerful in those days.
  3. No heated rear windows. Few people bought aftermarket things such "stick on" heated windows, which prevented part of the rear window from misting. Or rear window heaters looking somewhat like the heaters for tropical fish tanks. Or a small fan to blow against the rear window. I liked the small fan best as it produced good results while using little power. Remember that current consumption was very important in those days. On today's cars with their alternators one can switch on a very high number of electrical items all at the same time and the system will carry the load, even when driving with the headlights on all day. Not so in the days of the dynamo.
  4. It was normal to use the speed of the car to get the air inside through the heater unit. The fan was only there if the car happened to be stationary. There were very few traffic jams and traffic lights. Also much less motorways, but the cars could move at a reasonable speed almost all of the time. Long waits usually occurred only for open bridges, closed railroad crossings, ferries or women. Not many tunnels, bridges, underpasses or overpasses then nor women's lib.
  5. It was normal to open the side windows for ventilation.
  6. The small quarter lights were used to help demist the windshield.
  7. It was normal to have pieces of cloth on board to regularly wipe the windows clean.

What to check and fix?

  1. Water thermostat
    On 9 out of 10 Fulvia's, Flavia's or Flaminia's that I find the thermostat is bad. Either is does not close at all or it opens much to early. Putting cardboard in front of the radiator to get the water temperature up does not make the heater work better. In fact it is counterproductive. It only helps to make sure the thermostat is fully open. The hot water coming from the engine prefers the path of least resistance, which is thus not the heater but the wide open thermostat, the thick short hose to the radiator, the radiator itself and back to the water pump through the thick hose at the bottom. A good thermostat is thus a conditio sine qua non. (Latin: "condition without which not" thus "absolutely necessary")
    Remove the thick hose at the top of the radiator to get to the thermostat. It is a copper thermostat screwed into an aluminium housing. It is fun to remove. It helps to drive around with radiator cleaner in the system for a couple of days first to remove some of the corrosion inside the thing. Use a hexagonal socket 41 and heat the thing up. I lack the courage to use a flame on the old aluminium and thus use the paintstripper. So far I always managed to get the old thermostat out although I do keep a spare thermostat housing at hand.
  2. Water pump
    The water pump must still have good capacity. The original ones usually do. However, there are imitation pumps which don't. One brand has an impeller which is pressed onto the shaft instead of bolted. It will come off. On one of my Fulvia's I had to replace the water pump 3 times in 6 months. I have now obtained a load of the right seals and ball bearings and rebuild the original pumps.
  3. Heater cock
    S1 Fulvia's have good solid old fashioned metal heater cocks. Open them (first note carefully the position of the arm and the small spring) and replace the rubber membrane. This membrane is the same as in Flavia's, Flaminia's, Appia's and many Fiats. Costs less then 10US$. The rubber has swollen after so many years and the cock will thus not open at all. In some cases the rubber was about to tear. In one case it did, which means loosing all the coolant. Clean and grease the parts of the cock (use grease which is friendly to rubber). Make sure that the small disc at the bottom of the spindle rotates freely. This small disc should go INTO the small cavity at the top of the membrane. When fully assembled and mounted again, makes sure the Bowden cable opens and closes the cock fully.
  4. Heater matrix
    It looks like a small radiator and is inside the heater.
    One approach is to flush it using the garden hose. Remove the heater hoses from the heater cock and the bleed cock and connect one to the garden hose. Alternate the heater hoses several times until the water coming out is completely clean.
    If the unit is really badly clogged, the trick of the garden hose does not work. You then have to remove the heater, which is not terribly difficult (compared to the heater on an S2 or S3 Fulvia).Take the matrix to the radiator shop and ask them to put in a new core, which should cost no more than US$35. I never bother with the garden hose and just take the matrix to the radiator shop. I hate cold cars in winter.
    When assembling the heater unit again, make sure the metal plate under the matrix goes in the right way. I sometimes find these plates mounted the wrong way around. One side of the plate is bent at 900. This should be pointing up and be behind the matrix so that the bottom of the mixture flap closes against it when the flap is in the full hot position. Make sure there is no leakage of cold air around the matrix when the mixture flap is in the full hot position. The plate at the bottom of the matrix that I just mentioned should be bent a bit to achieve this. Use foam, rubber or metal to plug all cold air leaks.
    In all the heaters I did it was possible to have a bigger core put into the matrix. I am not sure it helps, but as I said, I hate cold cars.
  5. The heater fan
    On coupes the almost hopeless fan is inside the heater mounted on a metal plate. The impeller or rather expeller is on one side and the motor on the other side. If the motor does not turn, spraying WD40 on the spindle bushes will often help. If not, you have to have it fixed by an electrical shop. When assembling the fan back onto the plate, make sure the gap between the impeller is just small enough to avoid unnecessary leakage and just big enough to avoid the expeller scraping the metal plate. If the fan makes a heck of a lot of noise, the impeller is probably touching the plate.
    On the 1C the fan is in the metal intake unit just behind the grille. It is one of those medieval useless fans like in the Flaminia's (which at least have two fans). One day I will try to fit a computer fan.
    On the other berlina's the fan is under the bonnet in a round metal unit attached to the firewall. These fans are pretty good.
    On my S1 coupe I have rewired the fan and feed it directly from the battery through a relay. The relay is switched by the switch on the dash and mounted directly under that switch. It did really improve the turning speed of the fan.
  6. Hoses
    While you are at it, check the hoses. Heater hoses are destroyed by oil. I have not yet figured how to get the oil filter off without spilling quite a bit of oil. This oils often lands on the heater return hose and collects at the lowest point, which is near the bleed cock. As a result the heater hoses are usually pretty bad on both sides of the bleed cock.

If you do it all right, you will be able to turn an S1 coupe into a sauna on a cold winter day. Have fun.


Useful additions from Andrea

  • Oil stains can be removed from rubber hoses with a rug soaked in pure alcohol.
  • Put rugs around the oil filter base when taking the oil filter off.
  • Modern coolants have a finite life and should be completely replaced every two years.
Omicron Lancia Spares and Restorations
pre-Beta Lancia spares
and restorations
Repair, service, restoration
Fulvia Flavia Flaminia