The engine intake manifold is used to control air and fuel into the cylinder head combustion chamber. Most intake manifolds utilize engine coolant to help cool and distribute coolant into the cylinder head (s) and then down into the engine block. If the gasket that seals the intake manifold to the cylinder head fails it can allow coolant to enter the intake port and then the combustion chamber. To check for this condition the intake manifold will need to be removed. Once the intake manifold has been removed inspect the gasket. If the gasket has rotted or dilapidated between the intake port and the cylinder head it could allow coolant to transfer into the cylinder head. Replace the gasket with a new unit and reassemble. If the intake gasket is ok continue below.
Anytime you have coolant in the combustion chamber and the intake gasket is ok, the engine must be disassembled to locate the failure. These options are not so pretty. There are three remaining causes for coolant to enter the combustion chamber and all require engine disassembly. This can be tricky because the repair overlaps and it is difficult to tell which one is causing the problem before disassembly. For example: A repair shop has told you the cylinder head is cracked, and as they start disassembly they can discover it was the intake manifold gasket that has failed. It's up to the honesty of the repair shop to alert the customer the repair will be less. Or the opposite can happen, example: A repair shop has told your engine has a blown head gasket, once the disassembly is complete they inform you the head gasket is ok, and the cylinder has been pressure checked and is ok. This only leaves the engine block as the failure and must be replaced to repair the problem, and that can be costly.
Tuesday, February 24th, 2009 AT 2:41 PM