Mercedes M273 Leakdown test

Question by swaywithme posted 3 months 3 weeks ago in Mercedes-Benz

I have done leakdown tests on other cars I've owned but they all had manual transmissions which allowed me to 'lock' the engine from spinning when applying air pressure to a cylinder from an air compressor.

How do I keep the engine from spinning now that I have a Mercedes E550 with an automatic transmission when doing the leak down test ? I know there are flywheel locking tools but I was looking for an easier way to accomplish the lock.

I was also thinking of using less pressure (I used 100psi when doing the other tests) but am concerned that I may not get very accurate results.