Mack RD Truck Engine Parts & Cooling

Frequently Asked Questions About Mack RD Truck Engine Parts & Cooling

What years and models of Mack RD trucks are these engine cooling parts compatible with?

Our Mack RD engine cooling parts are designed to fit RD600, RD688, RD690, and RD800 models from 1990 through 2004. Always verify your specific engine model (E6, E7, or E9) when ordering radiators, water pumps, or thermostats, as cooling system configurations can vary. Check your VIN plate or contact our parts specialists with your truck's serial number for exact fitment confirmation.

How difficult is it to replace a radiator or water pump on a Mack RD, and what tools are required?

Radiator replacement typically takes 3-4 hours and requires basic hand tools, including socket sets, screwdrivers, and pliers. You'll need to drain coolant, disconnect upper and lower hoses, remove the fan shroud, and unbolt the radiator mounting brackets. Water pump replacement is more involved, requiring 4-6 hours and potentially special pulley removal tools. Many customers tackle radiator swaps themselves but opt for professional installation on water pumps due to belt routing complexity and torque specifications.

What's the difference between aluminum and copper/brass radiators for Mack RD trucks?

Aluminum radiators offer superior cooling efficiency and are 40-50% lighter than copper/brass units, reducing front axle weight. They feature wider tubes and better heat dissipation but can be more susceptible to electrolysis if coolant maintenance is neglected. Copper/brass radiators are more forgiving with coolant quality, easier to repair if damaged, and typically last 15-20 years. Aluminum units generally provide 15-20% better cooling capacity, making them ideal for heavy-haul applications or warmer climates.

Which coolant type should I use, and how often should cooling system components be serviced?

Mack RD trucks require heavy-duty diesel coolant meeting ASTM D6210 specifications. Use either conventional green coolant (change every 2 years/200,000 miles) or extended-life coolant (change every 5 years/500,000 miles). Never mix coolant types. Replace thermostats every 200,000 miles or when replacing water pumps. Inspect hoses annually for soft spots, cracks, or swelling. Replace coolant filters every 50,000 miles or with each oil change to prevent cavitation damage.

What are the warning signs that my Mack RD needs cooling system repairs?

Common indicators include temperature gauge reading above 200?F under normal loads, coolant loss without visible leaks (check for white exhaust smoke), fan clutch engaging frequently or not at all, coolant in the oil or vice versa, and crusty white or green deposits around hose connections. Squealing or grinding from the water pump area indicates bearing failure. Address these issues promptly - overheating can warp heads or damage cylinder liners, leading to costly engine repairs exceeding $10,000.