the problems never end … since I have the car I always top up the coolant at least every 40/50 days … then I had the engine redone and I hoped to solve it but no! I tried with an additive that should have avoided water loss … the situation has improved but it definitely still evaporates from some micro-holes somewhere … obviously I don’t lose it in liquid form, there is no visible loss … so I think it evaporates … are for the final solutions … change radiator ??
Don’t understand how it could evaporate - to evaporate there would have to be an open path to the atmosphere - sounds like you have an undetected leak - one that is drying up by the time you check it, such as from the water pump shaft - there is usually a “weep hole”, located on the bottom section of the shaft housing - when the shaft seal starts to wear out, the coolant will leak through this hole - purposely designed to let you know the seal is getting worn - the engine heat will dry up the small amount of leaking coolant, but a stained area would be seen - also, possibly a block “freeze plug” may be leaking - the block heat may dry up the liquid so may not see any sign on the floor, but tell-tale area should be the hint - if the overflow container is too full, at cold temp, then coolant may be going out of it when engine is running, and pressure relief radiator cap is sending coolant to overflow tank and out to road - overflow tank should only be half full when cold so as not to allow air to be returned to coolant system - check pressure cap(s), overflow tank level, water pump shaft weep hole (use mirror), freeze plugs - if nothing external, then loss of coolant would have to be internal gasket failure.
First thing to do is have the system pressure tested: that’s best done with the spark plugs out, where are you can observe, by listening, if you hear leaks into the cylinders.
The system should hold pressure overnight just fine: if it doesn’t, there’s a leak somewhere internally or externally, and that’s where the problems begin.
I absolutely rule out a head gasket problem, the engine was done by professionals and is a swiss watch … I must check the pump and the rest of the suggested parts
Until you do a cooling system leak test, you cannot assert that.
The good thing about a coolant leak, well actually the ONLY good thing about a coolant leak, is that you can ALWAYS smell it if it’s leaking outside the engine. So you have 3 conditions …
Smell coolant and can see the leak … A no brainer
Smell coolant and can’t see the leak … Could be a very minor “weep” that’s actually drying because of the engine heat before it starts to drip. It will usually build up like a crust around a hose.
Can’t smell coolant but you’re losing it. … Almost always the result of coolant being drawn into a cylinder and burned off.
One other possibility is that if the engine is running hot, coolant is being forced out of the header tank into the plastic overflow tank tnside the left fender well. If the overflow tank is leaking the coolant wouldn’t be drawn back into the header tank as things cool down. But again you would definitely smell the leaking coolant.
You can see where the coolant was being drawn into the #1 cylinder from the water gallery because of the failed head gasket on my engine last year.
I would start with ruling out the seal on the filler cap, they age and can go hard and steam can escape when the engine is at running temperature. The control valve for the heater which is mounted quite close to the bulkhead/ firewall is also a possible suspect. It can drip but because it is hidden under other hoses and in an awkward place it is difficult to spot and the coolant evaporates on the hot engine before you notice it. You could also have a small coolant leak inside the car from the heater matrix or hoses/ clips. Any coolant drips will be absorbed by the sound deadening and carpets so again you wouldn’t notice it. The best advice is to have the cooling system pressure tested as has already been suggested.
the system has been tested … it is in order, but the cylinder head gasket has been redone and the leak was there before as now … let’s talk a little but it is there!
…meaning, it was subjected to a comprehensive pressure test?
The mechanic told me yes…