Spray starter fluid where you suspect a leak when the engine is idling, engine rpm will change if it draws in starter fluid (spray a little straight into the intake and you'll see what I mean). WD40 and similar will probably work too, just not quite as good. Remember to keep a fire extinguisher nearby.
If you are talking about internal remove PCV block that hole in valve cover start engine now hold your hand over the breather hole in the other valve cover and see if it builds pressure or it draws vacuum if it draws vacuum you have a leak at the lower intake gaskets or a hole in the bottom of the intake.
We use a smoke machine now. If you don't have access to one then there's an adaptor for small propane bottles that pushes a small amount of propane out a hose when you push a button. CA smog repair stations are required to have one. They work great. No fire extinquisher necessary ( but still a good idea).
Hi, I'm having an issue with oil wet plugs and I'm thinking maybe an internal leak. Would this way also work with an early 283 with draft tube? I tried plugging the draft tube and checking the fill tube but got no pressure or vac.
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