🔍 Key Concepts

• Trace the piping from numbered coolers 3, 4, 5, and 6 to see which ones connect to the charge air cooler section of the engine (the bundle around item 24). • Remember that charge air coolers are installed in the intake/charge air path, not in the jacket water or lube oil systems. • On many main engine central cooling systems, the charge air coolers usually form part of the low‑temperature (LT) fresh water circuit, often with two stages of cooling.

💭 Think About

• On the drawing, which of the coolers (3–6) send their outlet lines directly to the connections marked J and K on the upper heat exchanger (around item 24)? • Which coolers feed the engine jacket water or other equipment (connections L and M around item 23), and can therefore be ruled out as charge air coolers? • If there are two separate cooling circuits to the charge air cooler (for example, high‑ and low‑temperature stages), which pair of coolers provides those two separate cooled water supplies?

✅ Before You Answer

• Verify which coolers have outlet piping leading to the upper bundle around item 24, not to the engine block 23 or to lube oil/fuel equipment. • Confirm that the selected pair of coolers each has a separate seawater inlet valve (A–D) but both discharge into lines going to the charge air cooler connections J and K. • Make sure the remaining coolers clearly serve other functions (jacket water, lube oil, etc.), so your chosen pair is the only logical match for the charge air coolers.