How do you test for an intake manifold leak?

Answer 1

I just went through this same problem with an old Montero. Carb cleaner spray is your best bet. Spray all along the intake to cylinder head, then around the fuel injectors, vacuum lines, throttle body to intake, etc. When you hit the spot where the vacuum leak is the idle will smooth out. Don't forget to also spray around you power brake booster (it's vacuum assisted) and all of the vacuum lines under the hood. Don't worry about the carb cleaner igniting, I've used this method for years and never saw this happen. The gentleman above me probably saw a mechanic use starter fluid instead of carb cleaner. I would not use oil. For one thing it will make a mess of your engine, it's not designed for ingestion into the intake air stream and it will not evaporate quickly like carb cleaner spray.

Answer 2

Intake Manifold Vacuum Leak

Answer 3

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RE:
How do you test for an intake manifold leak?

Answer 4

Spray a carburetor cleaner or a parts cleaner on the edge between the intake manifold and the cylinder head. That's the most common place for a leak. If the intake manifold is leaking it will suck in the cleaner and probably cause the engine to miss or run neurotically.

Good luck.

Answer 5

If you're gonna use carb cleaner to check for intake leaks, you'd better be darn sure you don't have a spark plug wire arcing anywhere.I saw a mechanic set an engine on fire doing that same thing one day. I'd use something like engine oil in a squirt can and squirt it along the intake and listen for the engine to smooth out when the oil covers the leak.

Answer 6

I agree to a point, use carb sparay to spray around the intake gasket areas. Once you find a leak you will know right away, the engine idle will pick up and smooth out. It is a split second seal at the damaged area. This just tells you where the leak is. You still need to remove the intake and replace the gaskets. Unless you have one of those plastic intake manolds. They tend to crack, so you will need to buy a new intake and replace both the intake and gaskets.
good luck.............

Answer 7

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only sure fire way is bring to shop and have smoke test done