spitting/leak cooling water out off the "coolant reservolt tank"

[Sasquatch]

If you have a compression tester you can do this at home. My compression tester allows me to either connect the gauge to it or an airline.
Your engine could last a long time as long as it does not start sucking in the coolant.
If its only a small break in the gasket it may only allow compression out during the compression or exhaust stroke and not coolant in on the intake stroke. Have seen this in the automotive world. Also had this happen on my old 02Viper.
What does the oil look like? If the oil level seems to rise a bit and it has a milky/light brown look to it then you have coolant entering the combustion chamber and will be losing the engine soon if not taken care of.

Yep I had a motor that would pressurize the system and leak out the rad, what was happening is the hot compression gasses on the power stroke (after the plug ignites the fuel) were leaking by the gasket into the water port in the head and then carried to the rad where they burst into little puffs of steam super heating the air causing the cap to open because the air pressure would rise beyond the cap pressure and vent steam but the motor never overheated till the coolant was low because the leaking was turning water to steam but the water once cooled by the rad was cooling the motor so the temp gauge seemed normal. You could see the bubbles in the rad. It would only make 100 miles till boil over it was leaking so bad yet it never sucked any water into the cylinder.

I changed the head gaskets and problem solved. As Stiener has said a pressure check on each cylinder can detect the leak. I would do a leak down test on each cylinder and see if the water level rises. Problem is the motor may only leak when the motor is hot and the cylinder pressure on the power stroke is high. Leak down test is only about 125pds cylinder pressure when the motor running the pressure is much higher. From the sounds of what you are saying a leaky head gasket is my bet.

A dealer can do a leak down test, they are usually performed to test valve leakage but they can detect a blown head gasket as well.

 

[YammyRX1]

I didn't read anywhere that you tested the coolant to see where the freezing / boiling points are. The antifreeze raises the boiling point so if the mix is weak it will boil at a lower temperature- hopefully the dealer checked that. A different reservoir will rule out the plastic seal being bad where it meets the cap. You should put a temp gauge on the sled so you can see what's going on in real time.

 

[Biro]

hello, just start to tear down the engine, and i wondered if it could just be the o-ring and the the head cover gasket, if you guys see on the picture it looks like it have been leaking there inn to the cylinder head cover. i was thinking on just changing the o-rings and cylinder head cover gasket.

 

[carsrtoys4me]

The gaskets may be leaking, but your problem isn't there. Only fluid under that cover is motor oil.
Sounds to me like a bad headgasket. I have seen the exact issue you describe several times on various cars/trucks, usually a bad head gasket or cracked head.

 

[Jim04RX1]

You can presurize cylinders as easy as using a rubber tipped blow gun if you have an air compressor. Head gasket problems can go approx. 4 different ways. External coolant leak. Internal (in the oil), Comustion chamber (out exhaust), Back pressure so to speak(compression thru coolant passages back to tank. A possibility is air in the system.
But I agree with Cars, A cracked head or compression in the cooling system does not have to be very noticable as far as runability.