what is the best tecnique to find a vac leak? process to follow?

the 1992 500 sl tends to idle arraticaly at times, specialy when the ac is not on. Any ideas as how to find the culprit. I took the air cleaners out and found a dried out tubing but can't find any more suspects. There is a line that I can see in front of the engine by thermostat but can't tell where ir goes.

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Thanks, Juan

Get a Vacuum pump and a gauage.



Do a search, It's been pretty well covered.

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

with the car running, spray brake clean, or parts cleaner on the engine, when the engine stumbles, check where you were spraying