Head gasket failure:

TYPES OF HEAD GASKET FAILURE

External Coolant Leak - Coolant leaks out along the edges of the gasket from an internal coolant passage. This is often the result of loose or broken head bolts.

Combustion Chamber to Coolant Leak - Combustion pressure forces its way past the armored skirt on the head gasket and into a coolant passage.

Combustion Chamber to Combustion Chamber Leak - Combustion pressure forces its way past the armored skirt on the head gasket and into an adjacent cylinder.

Oil Passage Leak - Oil leaks out along the edge of head gasket from an oil passage.

SYMPTOMS

External Coolant Leak - Coolant is visible leaking between the head and block.

Combustion Chamber to Coolant Leak
- White smoke in exhaust.
- Rapidly overheats.
- Emits coolant from spark plug holes during a compression check.
- CO (carbon monoxide) detectable in radiator.
- Spark plugs fouled with coolant.
- Oil contaminated with coolant.
Combustion Chamber to Combustion Chamber Leak
- Low compression in two adjacent cylinders.
- During a compression check, while one cylinder is on its compression stroke air is emitted from an adjacent cylinder and then drawn in during the intake stroke. This makes a very distinctive "whoosh-wheezing" sound.
- During a leak down check, air is emitted from an adjacent cylinder
HOW TO VERIFY THE PROBLEM
- Pressure check the cooling system and visibly inspect the block to head sealing surface for signs of coolant leakage.
- Remove all spark plugs and inspect for signs of coolant contamination.
- With all of the spark plugs removed, crank the engine with the starter for several revolutions. If a combustion chamber to coolant leak exists, coolant will be expelled from the associated cylinder.
WARNING: Keep clear of the engine compartment while performing this test. Coolant may be expelled from the spark plug holes with great force. Perform this test only with the engine cold.

- Perform a compression test of all cylinders while observing the radiator coolant level. Low compression on two adjacent cylinders or air bubbling out of the radiator during the compression check may indicate a head gasket problem.
- Inspect the oil for signs of coolant contamination.
- With light contamination, the oil will a light creamy coffee color.
- With heavy contamination the oil may appear thick and light tan in color.
- If the engine has sat for a while, the water and oil may have separated. While draining the oil, the coolant will drain out first, followed by the oil.
NOTE: Oil contaminated by coolant may also be caused by an intake manifold leak.
- Perform chemical combustion leak check. Any evidence of combustion gasses in the coolant indicates a head gasket leak.
- Perform cylinder leakage check.
Watch for bubbles in radiator (combustion chamber to coolant leak).
Listen for air in adjacent cylinder (combustion leak between cylinders).
NOTE: A cylinder leakage check utilizes regulated low pressure air to pressurize individual cylinders.

__________________
All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic