Leaky radiator diagnosis I have a leaky radiator with multiple pinholes on the core and a failed header-to-tube joint. It all seems to be happening in a random pattern. What do I do? Over or under treatment of coolant chemical can make the coolant very corrosive. If you’ve checked and found no problems with the coolant treatment chemical levels, here are some possible causes and solutions. 1. Electrical grounding through the radiator. Most radiators are mounted on rubber and not directly grounded. Because of this, the electrical circuits from aftermarket electrical accessories mounted directly on the radiator or its frame may be grounded through the coolant to the engine block, which rapidly erodes the radiator core. 2. Combustion gases cause aeration of the coolant. This may cause loss of coolant, which will rapidly erode the radiator core. Solution A coolant system pressure test will confirm the source of the problem. If pressure is low, aeration is the cause. If either of the above causes is pinpointed as the root of the problem, make sure to inspect the water pump impeller, since it may also be eroded. Advice courtesy of International Bus Vehicle Center. Visit International at www.InternationalDelivers.com. Remove ink, oil stains Citrol Degreaser, a heavy-duty, biodegradable product from Schaeffer Mfg. in St. Louis, can be used to remove ink from painted surfaces and vinyl seats. Citrol is available in 5-gallon pails of super-concentrate or ready-to-use spray cans. For more information, visit www.schaefferoil.com.