Hi guys Should i start by saying sorry for bad English
anyway in three months i have changed my thermostat my fan motor the other fan motor my radiator radiator cap the aluminum thing that connects the hoses to the engine and holds the thermostat i'm not sure what it's called in English and the car still have temperature problems it used to overheat now it goes below normal then overheat then goes to normal again and every time I check the radiator I find it a little bit low in water so the question is is it a head gasket or my car is just haunted?

 

Check your oil for coolant. Sometimes you will see excess smoke billow out of tail pipe or a white residue on oil cap.

Do you smell coolant inside your car or while driving. Sometimes it can leak under pressure and evaporate on a hot engine.

Is your Radiator ok? Plugged? Clean?

The most important question is have you bleed the air out of your system properly? You need to typically run the vehicle with the heater on while filling it with coolant for longer than you may think. This is a very good way to fill and bleed air out of the system.

Amazon link for Coolant Funnel:

http://a.co/iYlbsQA

If you use this never fill it too much since the coolant will warm up and expand and it could over flow from the funnel. Just keep it full enough so it will drain while the car is running and circulating coolant through it while burping the air.

Some things you can try also is a complete radiator and coolant system flush where you actually use a product to clean the system and run water through the radiator and engine block until it is very clean.

Here is a good youtube video:

 

Loss of coolant is measurable at the reservoir. What can you tell us about it actually overheating??

For one, don't believe the instrument gauge. It is a weak link and the sensor is known to fail.

If the coolant reservoir has steam vapor pushed into when the engine is hot and that action forces the reservoir to overflow, yes, it's likely the engine is overheating. This is usually accompanied by steam cloud from under the hood. But it could be as simple as a defective cap too. Does this happen?

In short the coolant system is a closed system and if any leaks exist it will not be topped off (filled up) during the cooling cycle when the engine is off. The cap plays a huge roll in function. If the block is filled full and is air free, when the engine gets real hot it may allow some coolant to push from the block into the res. When the engine cools, the coolant volume decreases and the system forms a vacuum whereby the caps inner valve allows coolant to be sucked from the res to the block.

If there are ANY LEAKS the block side never forms a vacuum refilling itself during cool down. In this scene it can slowly loose coolant and overheat.

Do a pressure leak down test. Also confirm the caps inner seal to the radiator is clean and flat. Confirm the caps inner seal and that thin disc form a good seal.
All the rest is find the obvious leak should one exist.