Use the diesel leak detector fluid with the Lisle 75500 Combustion Leak Detector
Indicating fluid changes from red to yellow when exposed to diesel combustion gases in the radiator
IMPORTANT: You must also order a Lisle 75700 Hand Vacuum Pump Adapter to use with 75500 Combustion Leak Detector Kits manufactured before June 2002. 75500 kits manufacted after June 30, 2002 include the new red adapter.