International Lancia Forums

last weekend I experienced my first blown headgasket. The sudden pressure in the cooling system caused the radiatorhose to split. Hence the enginebay covered in 3 litres of coolant (the rest came out of the exhaustpipe...). While repairing this damage which fortunately seems to be just the gasket and the hose I was thinking about installing some extra warninglites. Like: Low Oil pressure light. (Pressure transmitters can be found with an extra contact for a light) and High watertemp light. On the track you are better warned by a big red light and not by a small gauge going up. According to this incident I believe the watertemp sensor is placed in an unconvenient location. When the waterlevel drops the first thing to go dry is this sensor. Might the bottom of the radiator be a better location?

The early Flavia's and I believe the Fulvia 1C had the thermo senders in the top of the radiator. This is bad for two reasons:
1) coolant only flows into the rad if the thermostat is open
2) if the water level drops the sender goes dry

If you put the sender in the bottom of the radiator you avoid 2) but 1) is still a problem

I think in the Fulvia the sender is in the right position. It is right where the water comes out of the engine and just before the branch off to the by pass and before the thermostat.

If coolant level drops the sender will not fall dry as long as the waterpump is able to find coolant to pump up unless the perhaps you have a massive leakage such as when the upper rad hose comes off the thermostat housing.

To avoid mishaps such as hoses coming loose, make sure the pressure rating of the rad cap is low enough. The factory spec is 0,35 bar. I have not been able to find anything lower than 0,5 bar which I use on some of my Fulvia's.
If anybody knows where to source 0,35 bar rad caps let me please know

0.35 bar is about 5psi - I have never heard of this rating? 4psi is very common, pretty much the standard up to the early 70's and easily available - any vintage or classic car garage should be able to get them (loads for sale on ebay). I have looked through all my documentation and can find no reference to the pressure setting of the water system - where did you find it ??

I will have a chat with my vintage chums and see if they can help.

Back to topic - before you put the head back check it is flat !! Personal experience of this oversite !

regards
Neil

I prefer to use a higher pressure cap - I use a 15 psi (one bar) one - especially when the car is to be used on track days as William's is.

Obviously hoses and their clips etc. must be first class. A little water lost means the engine heats a little quicker and blows more water out and so on until the head gasket gives up or a piston picks up or worse.

No wonder the racers use high-pressure caps; some of the Americans run their engines very hot and the very high pressure caps are probably necessary to keep the water liquid (i.e. it is run over normal boiling point).

Steam itself is actually a good coolant in theory, but Rolls-Royce's flirtation with it for the Goshawk engine was a wash-out, so I do not recommend it for Fulvias!

Paul

Neil, the pressure rating for the cooling system is not in the documentation. At least, like you I have not been able to find it. The value is however marked on original radiator caps and certainly not too different from the 4psi you mention.

William, one other question was the warning light. I use one for oil pressure. When it comes below 1 bar it lights. Make sure you have it centrally in front of you. Any other location will not be seen while cornering hard. And forget about putting an extra one in front of the co-driver as I did: He really never looks and really doesn't care.

By this light I found out that pressure is dropping to critical levels in fast left hand corners with modern tyres. Typically those that you lift your inner rear wheel and have better things to do than watch your oil guage....

Warning light for water temp I would not care about. You will see that if you loose all your water at once, the temp it senses drops and you would get no warning. Better put on your heater on the track. If it is getting colder, you are in trouble....

Another thing that I will fit for rally use is a warning light that warns if something is wrong with the electric curcuit. There are all kind of problems that can (and will) occur with it that do not light the standard warning light. Most recent one was the big bolt coming loose that goes through the pulley into the crank. Tension dropped on the alternator belt and voltage was swinging. But as before, meter is in front of codriver so he had no clue.... Bolt worked its way into the radiator, but I realized it in time (voltmeter). Also learned that night how you can repair a radiator with a big hole in it. Still finished the rallye as 6th.