93 toyota previa having white smoke while starting and stu-off while running on the road.

thx so very much ... by any chance it will have any other damage for the engine.. cause we checked the spark plugs which find 3rd and 4th cylinder sparkplugs had corrsion with white spot built on it already.and it is possible to replace the head gasket without take the engine out of the car？

Yes. The entire engine does not have to be removed, the head(s) can be removed and replaced with the engine in place

thx davidH25. did u have any experience on replace the head gasket for previa cause we try to do it by ourselve but donot know it is difficult to work on it. by the way we for sure not willing to get a used replace engine for another thousand dollar for such old car with no warranty. As result if we can get the head gasket for just 100 which will try to fix it. ^v^ we still love this car

How to Replace a Head Gasket in a Toyota Previa Van Locate the battery. Use an adjustable wrench to remove the clamp bolt, which is fixed to the negative battery terminal. Pull the negative cable away from the terminal. Locate the drain plug on the radiator. The plug will be at the very bottom. Place a drain pan directly underneath the drain plug. Remove the plug and drain the coolant into the pan. Once the radiator is empty, reattach the drain plug. Use your wrench to remove the mounting bolts from the air filter unit, alternator and exhaust manifold. Lift them all from the vehicle and place them in a safe area, as you will need to reattach them later. Ensure you do not damage the parts in any way. Use your hands to remove the coolant line and lower and upper radiator hoses from their connectors. Simply pull them out with your hands. Remove the mounting bolts attached to the timing belt cover and lift it from the engine. This will give you access to the head gasket. Remove the bolts attached to the cylinder head, starting at the far left-hand side and working your way around in a cross-hatch pattern. Lift the cylinder head off the engine block and move to one side. Remove the damaged head gasket. Install the new head gasket onto the engine block. Place the cylinder head back on top of the gasket. Reattach the cylinder head bolts to a torque of 23 foot-pounds using a toque wrench. Place the timing belt cover back in place with the mounting bolts. Insert the coolant line, as well as the upper and lower radiator hoses, back into their respective connectors. Place the exhaust manifold, air cleaner unit and alternator back onto the engine and secure in place with the mounting bolts. Screw the radiator cap off the radiator and pour coolant back into the radiator. Attach the negative cable back onto the battery and secure in place with the clamp bolt.