707001EX | Genuine Paccar® Cylinder Head MX-13 - Kenworth T880, 2024

1. Seals the Combustion Chamber

Together with the head gasket, it creates a tight seal over the cylinders so combustion gases don’t leak.

2. Houses Engine Valves

Contains intake valves (air/fuel in) and exhaust valves (gases out)
Often includes valve springs, lifters, and rockers

3. Directs Airflow and Exhaust

Provides paths (ports) for air-fuel mixture to enter and exhaust gases to exit

4. Holds Fuel Injectors or Spark Plugs

Diesel engines: injector nozzles mounted in the head
Gasoline engines: spark plugs are installed here

5. Provides Cooling Passages

Contains coolant channels to absorb and carry away heat from combustion

1. Engine Overheating

Cracks in the cylinder head can cause coolant leaks or improper cooling.
Often one of the first and most serious symptoms.

2. White Smoke from Exhaust

Caused by coolant leaking into the combustion chamber.
Indicates a cracked head or blown head gasket.
Smells sweet and may leave residue at the tailpipe.

3. Milky or Frothy Oil (Coolant in Oil)

Oil looks like a milkshake on the dipstick or under the oil cap.
Caused by coolant mixing with oil due to internal cracks or gasket failure.
Leads to poor lubrication and severe engine damage if ignored.

4. Loss of Compression / Misfires

Cracked or warped cylinder head causes compression loss in one or more cylinders.
Engine runs rough, misfires, or has poor power.
May trigger check engine light or error codes.

5. Coolant Loss with No Visible Leak

Constant need to top off coolant without external leaks
Coolant may be leaking into the cylinders or evaporating in the exhaust.

6. Tapping or Knocking Noise

If the cylinder head is warped or cracked, valve train components may not seat correctly.
You may hear metallic ticking, tapping, or knocking sounds, especially at startup.

7. Contaminated Spark Plugs or Injectors

Wet or fouled plugs/injectors indicate fluid entering the combustion chamber.
Common in both diesel and gasoline engines with a head problem.

8. Check Engine Light or Fault Codes

May show up with codes for:
Cylinder misfires
Low compression
Injector issues
Overheating

9. Hard Starting or No Start

A severely cracked or warped cylinder head may prevent the engine from building enough pressure to start.

10. Visible Damage

On disassembly, you may find:
Cracks, usually between valves or injectors
Warping, often due to overheating
Erosion or pitting, especially in coolant passages