328 cooling liquid leakage

I had this on my 328, turned out to be a faulty expansion cap, bought anotehr for mFerrari UK (£15!!!!) which turned out to be a slightly higher rating and it sorted the problem

 

Yes it could be your cap but it may also be normal. When was the coolant last changed? After a coolant change it takes a while for the coolant volume to find equilibrium and stop leaking from drain hose- Mine is still occasionally dripping after two months but it will settle down soon.

 

Another cause could an air bubble somewhere in the system. Try bleeding using the radiator & thermostat bleed valves. Search the archives for bleeding procedures, I & others have written them up several times.

 

Buy a new filler cap.
Old ones (0.9 bar) are replaced by 1.1 bar dittos.

 

One thought here -

Radiator cap is the most common etiology (especially if original) with slight overflow drain. Depending on how diagnostically determined you are (i.e. replacing cap is simple), five main causes of reduction in AF levels:

1. Overheating/boiling off (incorrect mixture, engine variables, poorly-functioning radiator, failing water pump/belt)
2. Faulty cap - no longer able to hold sufficient pressure.
3. Internal leakage - typically ruptured cylinder head gasket (but would usually run roughly, overheat rapidly, and put out white smoke in exhaust)
4. External leaks - hoses/fittings/clamps. Notable areas on 328 are origin of heater hose at manifold and occult heater core leakage.
5. Overfilled system - (doesn't sound as if this is case).

Thread on JRVs board recently about replacement Alfa Romeo (?) cap for about $5 or as others have noted OEM is about $20-25. If you want to "prove" faulty cap prior to replacement most auto parts stores can test caps on pressure device (although unsure if you;d be able to find proper adaptor for this cap).

(everyone feel free to critique my analysis)

Carl