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Consequences of a Vacuum leak?

10K views 2 replies 3 participants last post by  towerymt 
#1 ·
My car has a very big vacuum leak. How will this negatively affect my car aside from the odd idle that it now has? Is it expensive to fix? Do I need to get it repaired now or can I wait several pay days from now?

-Poritz
 
#2 ·
Re: Consequences of a Vacuum leak? (Poritz)

Besides an odd idle a large Vacuum leak means your engine's ECU will not be able to properly control your fuel mixture and typically results in a lean condition. This can be very detrimental to an engine especially if it is turbo charged. Vacuum leaks are usually a result of a bad gasket or defective Vacuum hose. Depending where the leak is it could be a simple repair, such a hose replacement, or an expensive repair if you have a bad intake manifold gasket. I would have it looked at as soon as possible.

Doug H
 
#3 ·
Re: Consequences of a Vacuum leak? (defgh1)

A vacuum leak will allow the engine to suck in unmetered air (didn't pass through the AMM) and therefore there's too much air for the amount of fuel injected, and the mixture is lean. Severe lean conditions can damage spark plugs or burn exhaust valves. Exhaust gas temps are higher than usual, so the exhaust manifold and turbo will probably glow more easily. The turbo may run hotter, heating the oil & water than runs through it to higher temps.

The air leak probably leaks under boost if it leaks under vacuum. This means you're loosing metered boost pressure, so the engine sees too little air for the amount of fuel injected and it runs rich. Emissions are also affected by air leaks.

I would suggest you find and fix the leak. You're loosing power as a result.
 
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