Renault 19 cooling system problems

Problem: Heater does not work. 
Solution: The matrix may have an air lock in it, which is common after a coolant change. Or the flap may not work, 
              when you turn the heater knob to hot you should hear a faint thump from the centre console, the feel 
              through the control is not enough as the cable feels the same whether the flap is attached or not. You 
              can reach into the foot vents and move the flap by hand to check the heater knob should turn. 

Problem: When the heaters on I am sure I can smell coolant but it goes away once the heat is on cold. 
Solution: Leaky heater matrix, basically the matrix is a radiator and when the flap is set to hot air passes through 
              it gets heated up then comes out into the cabin causing the smell when its at cold the matrix is blocked 
              off from the air so it no longer smells. 

Problem: Coolant is ending up in the footwells. 
Solution: Change the matrix its bust good and proper. 

Problem: My car never heats up to the right temp. 
Solution: Either the thermostat is missing or it has failed in the open position. Change it/fit one as the car running 
              cool will increase engine wear. 

Problem: My car gets hotter than a nuclear reactor. 
Solution: The rad may be blocked, low system pressure, the thermostat may have failed in the closed position, 
              the fan doesn't work, the pump has failed, there is an airlock in the system, exhaust may have cracked 
              allowing gases to heat up a cooling pipe (a cracked manifold pumps hot air straight onto the pump and 
              metal pipe) or the head gasket (HG) may have gone. 

Problem: The gauge says the car is hotter/cooler than it really is. 
Solution: The sender may be dead, covered in corrosion, or simply a bad connection or wire. 

Problem: My car makes a screeching sound from under the cambelt cover. 
Solution: If the belts are tight and the tensioner is ok then its the water pump, the bearings have gone and you 
             may notice a slight dribble of coolant from under the pump. 

Problem: Whenever I stop the car usually after a long run I hear a hissing sound from the header tank. 
Solution: This is normal but it should only be for a few minutes after switch off, the cap is venting pressure out. 

Problem: When I squeeze a coolant hose i hear a hissing from the header tank much like when it vents after 
              switch off. 
Solution: The vacuum spring in the cap is stuck in the open position. The cap has 2 springs a large one (pressure 
              relief) and a small one (vacuum), when you switch off the pressure in the system pushes the large 
              spring so it opens letting air/excess coolant out and when it cools the small spring lets some air back 
              in, remember the coolant expands when hot and contracts when cold. When the vacuum spring opens 
              to let air in some coolant stuck in the cap may dribble back in as well this will make the small spring 
              sticky hence keeping it in the open position. Take the cap apart by popping the brown/blue top off with a 
              screwdriver and then clean the springs and other parts with a toothbrush and clean water. 

Problem: More a query, will fitting a higher pressure cap enhance the cooling system? 
Solution: Yes it will, increasing the pressure in the system raises the boiling point of the coolant it also forces the 
              coolant to completely fill out the water channels enhancing the cooling effect of the radiator. But if the 
              pressure is too high it may burst hoses or strain the pump, but this would really take a lot of pressure. 

Problem: So do I buy a higher pressure cap, mod my existing one or even just fit a oil filler cap? 
Solution: You can if you want fit a higher rated cap and you will not experience any probs. To mod your existing 
              one is easy, just get the big spring and stretch it out and this will increase the pressure of when it opens, 
              but you have no real way of knowing how much more pressure it takes, but I have done this mod to my 
              own caps. Fitting and oil cap will increase the pressure a lot, it wont vent or anything and would be a bad 
              idea as it may make hoses burst and stuff. 

Problem: My coolants brown. 
Solution: Common prob, this is rust which is caused by infrequent coolant changes, this also lowers the cooling 
              systems efficiency. 

Problem: My coolant disappears and it needs to be topped up constantly. 
Solution: The HG may have gone but usually results in the exhaust pumping out lots of steam and even oil in the 
              water and water in the oil. The head or block may be cracked internally. You may have a leak somewhere 
              in the system. Or you have an airlock that is either sorting itself or forcing coolant out the cap. 

Problem: The coolant level rises. 
Solution: When the engine is hot the level may raise by a few mm's. If it raises a lot then it may be a defective HG 
              or an air lock. 

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