A chronic problem with many Bavaria's is marginal cooling capacity. This situation can become acute with an air-conditioned car idling in traffic or when towing. If the stock cooling system is in a reasonable state of repair, the problem becomes one of inadequate heat dissipation by the radiator under conditions of high ambient air temperature and relatively low air flow. Shrouding the fan will improve low-speed air flow, but the tight confines of the engine compartment make this a difficult fabrication job. A far more effective solution is to increase the radiator's cooling area. It is fairly simple to substitute a 2" thick core for the stock 1.5" item. The stock end tanks and hoses are retained, and the radiator mounts require only the slightest modification. The thicker core increases cooling area by 1/3 and works beautifully. There is one catch -- $200+ for a custom radiator core and another $35 to install it.
After a good bit of investigation, I discovered a firm that could supply a 2" core for the Bavaria as a stocked item for $99.25. Installation is $35, and a circular guard to prevent fan contact with the core is $5 extra. This firm has agreed to sell the 2" Bavaria core as a separate item for installation by your local radiator shop or will perform the complete conversion on an owner-supplied radiator.
A cooler thermostat does not cure overheating; it merely delays its onset. A cooler thermostat coupled with a properly functioning cooling system is desirable because normal operating temperature can be tailored for optimum efficiency. My personal preference is for the 80°C unit rather than the 84°C item normally supplied in the USA.
The Bavaria fan clutch can be locked solid, but unless the clutch is malfunctioning, the end result is more noise without a significant improvement in cooling. If you must lock up the fan clutch, replace two of the four M 6x25-mm bolts that secure the fan to the clutch hub with M 6x30-mm bolts placed diametrically opposite each other to preserve balance. Other methods of locking the clutch usually result in imbalance or fan misalignment.
Author: John J. Spittle III