Lang whistle for cylinder leakage tester whistles on the compression stroke and stops whistling at approximately Top Dead Center. The Lang whistle for cylinder leakage features a quick coupler that connects directly to the cylinder hose on CLT-2 and CLT-4 as well as 74498 diesel adapter. The whistle is very useful to locate approximate Top Dead Center for cylinder leak testing, and can also be used to set approximate distributor timing.