what are the symptoms of a blown head gasket? THERE IS NO WATER IN THE OIL IT HAS PLENTY OF POWER BUT IS LOOSEING WATER at the back of moter but i cant tell where maybe heater hoses?
There are a number of possible symptoms:
Coolant leaks out of the engine block just below the head.
White smoke comes out of the exhaust, indicating an internal leak, and coolant going through the engine. This is a really bad scene needing immediate attention.
When the car is warm and running bubbles come up through the radiator when you (very carefully) take the cap off the radiator itself.
Bubbles come up through the coolant in the overflow tank.
You can lose coolant in many ways without a head gasket leak; though hoses and hose connection, through a leaking heater core (coolant smells in the car), through a leaking transmission oil cooler in the bottom of the radiator, water pump gasket, etc. Some leaks do not show up on your garage floor; they may only occur when the engine is fully loaded at highway speed and coolant may be lost from a connection just loose enough to yield to the addition pressure.
I would begin by driving the car at highway speed, pulling off on to a concrete surface, then shutting the engine off. This will raise the coolant pressure; if you have an external leak, you may spot some coolant escaping.
Your mechanic needs to do a pressure test of the cooling system and determine where the leak is. As mentioned, a head gasket leak into the engine can wreck the engine quickly.
When you start back up, look in the rearview mirror for white smoke coming from the exhaust. That will indicate an internal leak.