Thermal management specialists MAHLE has issued specific guidance on working with BMW radiators in its latest technical bulletin. MAHLE has reminded technicians that when installing a new radiator on certain BMW models, a short or long screw plug must be fitted, depending on the transmission of the vehicle. Some BMW radiators can be used for different model and transmission combinations.
These radiators are always supplied with both short and long screw plugs and seals, but it’s imperative that the correct part is fitted to avoid leakages or contamination. Vehicles with manual transmission should be fitted with a short screw plug, and vehicles with automatic transmission and an oil cooler fitted with a long screw plug.
MAHLE warns that using the incorrect screw plug in a vehicle with automatic transmission can cause severe damage, as it closes the additional connection to the oil cooler, preventing coolant from circulating. If the incorrect screw plug is installed on a manual transmission vehicle, coolant will escape at the unused oil cooler connection.
MAHLE also reiterates that despite the rule of thumb that manual gearboxes have short screw plug installations and automatics have long screw plugs, there are several BMW radiators available that can be used for different vehicle and transmission combinations: CR 455 000S / CR 1083 000S / CR 1088 000S, CR 1084 000S / CR 1085 000S / CR 1162 000S, and CR 1086 000S / CR 1087 000S / CR 1393 000S.
MAHLE advises that seals should always be replaced and coated with clean coolant prior to fitting, in order to prevent damage caused by dry assembly.