4952507 | Genuine Cummins® Oil Filter Cooler Head

1. Compatible Engine Models

This component is engineered specifically for heavy-duty commercial diesel engines. It is a direct fit for the following engine platforms:

• Cummins ISX Series (ISX15 / QSX15): This is the primary application. It fits heavy-duty, dual-overhead-cam (DOHC) and single-overhead-cam (SOHC) 15-liter Cummins engines.

• Signature 600 Series: Used on high-horsepower premium platforms built on the ISX engine architecture.

2. Common Vehicle Applications

Because it fits the ISX15/QSX15 engines, this oil filter cooler head is found in a massive variety of North American Class 8 heavy-duty semi-trucks, including:

• Peterbilt: Models 386, 388, 389, 567, 579.

• Kenworth: Models W900, T660, T680, T800, T880.

• Freightliner: Cascadia, Coronado.

• International: LoneStar, ProStar.

• Volvo & Mack: Older models equipped with Cummins power options rather than proprietary engines.

1. What is it?

This part is a heavy cast-iron or heavy-alloy housing block that mounts directly onto the engine block. It acts as the structural foundation where the engine oil filter spins on and where the internal oil cooler core is housed. It is engineered to withstand immense thermal cycling and continuous high oil pressure.

2. Core Functions

• Fluid Routing & Distribution: It splits and directs the flow of raw, hot engine oil coming from the oil pump, forcing it through the oil cooler tracks to shed heat, and then routing it through the oil filter media before it travels to grease the crankshaft, pistons, and valvetrain.

• Pressure Regulation & Filtration Safety: The head incorporates internal bypass valves. If an oil filter becomes completely clogged with debris or if the engine undergoes a freezing cold start with thick oil, these safety valves open automatically to ensure the engine is never starved of oil.

• Structural Leak Prevention: It features precision-machined mating surfaces and integrated gasket channels designed to isolate high-pressure oil lines from the engine's coolant jacket lines, preventing catastrophic internal fluid cross-contamination.

 1. Oil and Coolant Cross-Contamination (Milky Oil or Sludge)

The most definitive sign of a failure inside the cooler head assembly is the mixing of engine oil and antifreeze. If the internal barriers or gaskets fail, high-pressure oil will leak into the coolant passages, or vice versa.

• Look for a thick, chocolate-milk-like sludge under your oil filler cap or on the dipstick.

• Check the coolant overflow reservoir; if you see dark oil floating on top of the antifreeze, the cooler head or its internal gaskets are likely compromised.

2. Unexplained Drop in Engine Oil Pressure

If the internal bypass valves inside the cooler head become jammed open, or if the casting develops an internal structural crack, engine oil will bypass its restricted routes. This causes a noticeable and dangerous drop in oil pressure on your dashboard gauge, especially when the engine reaches full operating temperature.

3. External Oil or Coolant Leaks Around the Base

The cooler head is bolted directly to the heavy engine block. Over hundreds of thousands of miles, extreme thermal expansion can warp the housing or degrade the heavy-duty mounting gaskets. You will notice puddles or wet streaks of clean engine oil or engine coolant dripping down the side of the engine block directly beneath where the oil filter is mounted.

4. Engine Overheating Under Heavy Loads

Since this housing controls the flow of oil into the cooling core, a restriction or blockage within the header passages will prevent the oil from shedding its heat. If your engine oil temperature spikes rapidly while hauling heavy loads, or if the coolant temp begins to climb abnormally, the cooler head may be restricting proper fluid circulation.