Thump from passenger side engine compartment
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From: maine
Thump from passenger side engine compartment
'04 V-10 Upon start up, maybe 15-30 seconds later I get a thump sounds & feels like from the passenger side engine compartment, the other morning it was like a huge thump.
Will the vacuum pump do this?
I haven't put the tranny in gear, just idling. Everything runs fine, no lights on the dash, no increase in RPM, no squeaks, just a thump like something is engaging.
Will the vacuum pump do this?
I haven't put the tranny in gear, just idling. Everything runs fine, no lights on the dash, no increase in RPM, no squeaks, just a thump like something is engaging.
Fleet Mechanic
Joined: Apr 2008
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From: Vancouver BC Canada
It is very likely a flapper doohickey in the heater box (As you can see I am using the technical term here). This is very common, my truck does it, and I don't believe it is a problem
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Joined: Nov 2008
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From: Northfield, MI
Not to be technical, but it is the recirc door that makes the noise, not the blend door which is electronic and physically unable to move quickly. If there is a vacuum leak in the a/c system, the recirc door will slowly move to the open position. When the truck is started, vacuum rapidly builds in the system and the door will slam shut again, making the noise. This just means you have a minor leak in the vacuum system, probably not worth spending time searching for.
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Fleet Mechanic
Joined: Apr 2008
Posts: 1,724
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From: Vancouver BC Canada
Not to be technical, but it is the recirc door that makes the noise, not the blend door which is electronic and physically unable to move quickly. If there is a vacuum leak in the a/c system, the recirc door will slowly move to the open position. When the truck is started, vacuum rapidly builds in the system and the door will slam shut again, making the noise. This just means you have a minor leak in the vacuum system, probably not worth spending time searching for.
Mountain Pass
Joined: May 2004
Posts: 173
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From: WI
I also get this with my 03 CC V10. Mine sounds like someday is striking the firewall with a large hammer. Not only is it loud but I can feel it through the steering wheel, pedals and floor and it shakes anything I have lying on the dash. It doesn't do it every time I start the engine after its been sitting awhile, and I never change the selector from defrost/floor.
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