Super Duty Thunk
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Freshman User
Joined: Jan 2004
Posts: 39
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From: Londonderry, NH
Super Duty Thunk
In a post last fall, I described a thunk i heard under the right front side of my SD. Over the winter that thunk went away, but has come back with a vengence. Gonna take in to the dealer sometime this week. Hopefully they will be able to issolate it.Until then, any ideas?
Postmaster
Joined: Dec 2003
Posts: 3,130
Likes: 3
From: Massachusetts
Mine does it in the first few minutes after start up. It only happens when the heat or A/C is on. There is a valve that opens or closes and makes a thud. Sometimes it is relatively quiet and there are other times it is loud enough to startle you.
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Freshman User
Joined: Jan 2004
Posts: 39
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From: Londonderry, NH
Originally, mine only did it right after start up shortly after turning on the A/C (within 5 minutes of starting). But lately it happens with or with out A/C, and often after driving for 15-20 minutes.
Senior User
Joined: Jul 2004
Posts: 188
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From: Tehachapi, CA
I get the thunk on the right front side too. Happens when I start up but not every time. Turn the key and "thunk" one time and the motor starts. Always wondered what it was. Since it didn't seem to harm anything, I ignored it. Be interested to see if there's some explanation.
Post Fiend
Joined: Jun 2003
Posts: 5,643
Likes: 8
From: NE Texas
Have you guys done a search for this?
It could be the airflow door in your air conditioning system.
There's a fix here somewhere, but I can't think of the term to use right now.
Anyone remember the correct term for that sticking door?
I got CRS....
It could be the airflow door in your air conditioning system.
There's a fix here somewhere, but I can't think of the term to use right now.
Anyone remember the correct term for that sticking door?
I got CRS....
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Joined: May 2004
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New User
Joined: Feb 2004
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I have been to the dealer for this and it was verified as the blend door. I am told that as soon as the vaccume motor gets enough pressure the door releases. Take note that it wont do it if shut off and restarted within 5 min. But after 5 min. or so of sitting it will bleed off and do it again - Still to this day it scares the ***** out of me if I am manuvering in a tight space and forget about the little thump in the dash, sounds like I hit something when it lets go. Was told this is common and not abnormal - of course it is! ! !
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Postmaster
Joined: Aug 2004
Posts: 4,004
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From: North of Boston MA
The dealer is saying turn everything to "off" but if you do that, especially in the summer, you will have one hot vehicle when you get out of work. "OFF" will close the vent and allow no heat to escape unless you leave a window open too. I would leave it in "VENT" and live with the thunk.....I think.
