Symptoms of a Blown Head Gasket:
* White or milky-looking oil: This indicates coolant mixing with the oil. Check your dipstick.
* Coolant loss: Losing coolant without visible leaks is a strong indicator. Check your coolant reservoir regularly.
* Overheating: The engine overheats frequently, especially under load.
* External coolant leaks: Look for leaks around the head gasket area (between the engine block and cylinder head). However, the absence of external leaks doesn't rule out a head gasket problem; internal leaks are common.
* Compression test: Low or unequal compression in one or more cylinders suggests a problem with the head gasket sealing that cylinder.
* Exhaust bubbles in the radiator: A pressure test on the cooling system can reveal bubbles in the radiator, indicating exhaust gases entering the cooling system.
* Sweet smell from the exhaust: Coolant leaking into the combustion chamber will create a sweet smell (ethylene glycol) from the exhaust.
* Oil in the coolant: This is less common than coolant in the oil, but it's another sign of a blown head gasket.
Things to Check BEFORE Assuming a Head Gasket:
* Radiator cap: A faulty radiator cap can cause pressure buildup and lead to coolant loss.
* Coolant hoses: Check for cracks, leaks, or kinks in your hoses.
* Water pump: A failing water pump can cause overheating and coolant loss.
* Thermostat: A stuck thermostat can cause overheating.
* Radiator: Check the radiator for leaks or damage. Look closely at the fins and core.
* Head bolts: Loose head bolts could lead to pressure loss and eventual gasket failure, but this is less common.
Testing for a Head Gasket:
1. Pressure Test: A cooling system pressure test is crucial. A shop can do this effectively. This test pressurizes the cooling system and checks for pressure loss, indicating leaks. The pressure test is the most reliable way to determine if there's a leak *in* the cooling system.
2. Compression Test: A compression test measures the pressure in each cylinder. Low or uneven compression suggests a head gasket problem, but again, this could be caused by other engine issues.
3. Leakdown Test: This is a more advanced test that pinpoints where compression is escaping – potentially through a head gasket.
4. Block Test: A block test uses a chemical that detects combustion gases in the coolant. This is a quick and relatively inexpensive test, but it’s not always conclusive. A negative result doesn't rule out a head gasket problem.
Important Considerations:
* Age of the vehicle: A 1988 Ford Ranger is an older vehicle, and other problems are more likely. Address the simpler issues first before jumping to conclusions about a head gasket.
* Professional Diagnosis: If you're not comfortable performing these tests yourself, it's best to take your Ranger to a qualified mechanic for a proper diagnosis. Misdiagnosis can lead to unnecessary repairs and wasted money.
In summary, while the symptoms listed can indicate a head gasket failure, they can also be caused by other, less expensive problems. Always start with the simpler checks before moving on to more invasive and expensive tests. A proper diagnosis is essential to avoid unnecessary repairs.
