# 02' F-250 SD "thud" after starting



## infineon954 (Dec 12, 2004)

Here's the problem. When I start the truck, every once in awhile I can here a "thud" sound through the floor board. More or less on the right side of the truck. A friend of mine claims he has the same problem on his 02'. Whats the problem? And is it something to be concerned with?


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## echovalley (Dec 5, 2004)

Both of my 04s did that.The 05 doesn't


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## Brian Young (Aug 13, 2005)

I worked at a Ford garage up until last year, I never heard of this concern. It could be the starter or even some exhaust rattle. The Triton engine has a lot of torque and weak exhaust manifolds, (a lot of flex) thats why I'm thinking exhaust.


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## BDB (Nov 24, 2005)

For whatever reason it is the air conditioner compressor. Iv'e found if I leave the defroster on it make that thump, pretty consistantly. If it is off it will not do that. I try to turn it off when I start it then turn on the defroster on and it doesn't seen to thump. See what you come up with.


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## Brian Young (Aug 13, 2005)

BDB said:


> For whatever reason it is the air conditioner compressor. Iv'e found if I leave the defroster on it make that thump, pretty consistantly. If it is off it will not do that. I try to turn it off when I start it then turn on the defroster on and it doesn't seen to thump. See what you come up with.


Then its probably the vac. opening or closing the regulator to the heater box.


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## BDB (Nov 24, 2005)

It sounds like someone hits the frame with a 5lb hammer. I don't know if the heater box would be that loud and deep of a tone. But its possible if it snaps shut. If it gets pin pointed it will be nice to fix it. Till then its a Ford...


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## tawilson (Nov 21, 2003)

Yeah, it's a ventilation door. It's been discussed a lot on the Ford forum. Mine does it too, no sweat.


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## FSUPERDUTY (Jan 1, 2003)

ventilation door my 2000 did it once in awhile asswell ,very common!


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## ksland (Nov 27, 2002)

Funny, My GMC doesn't do that.


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## dag-otto (Sep 28, 2003)

ksland said:


> Funny, My GMC doesn't do that.


Somebody always has to be a wanker.

Both of my newstyle SuperDuty 03/04 do that. Usually when I just startup. I almost thought it sounded like leaf spring shackle settling. It's a bit concerning.


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## plowman350 (Jul 19, 2004)

*glad to hear it*

I'm glad mine isn't the only one.

2003 F350 Crew V-10. It's been driving me nuts. although I have to agree it sounds a LOT bigger than just a air flow door in the system. It sounds like a clunking U-joint or Tranny problem....but everything there checks out okay.

I see some of you claiming that its normal......has anyone discovered a fix to it? Or has any one been able to diagnose the problem with certainty?


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## tawilson (Nov 21, 2003)

As far as I know, it's not a problem, and there's nothing to fix. It's supposed to do it. Someday, when it doesn't do it, you'll miss it.


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## Pat M (Oct 19, 2005)

My 03 F250 with the 6.0L does it but my wife's 03 Excursion with the 6.0L doesn't do it.


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## mrfreeze (Jul 8, 2006)

*New to Ford sounds*

I just bought a 2002 F250 and have the same sound. After a while I figured it was somthing to do with the air intake.

I have another sound now which I will post...


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## MOW ME OVER (Jan 30, 2004)

Here is two service messages from Ford about the noise you describe. It sounds like the first message from what you are describing but I will still post the second message in case someone else does not know about it.

18304 1999-2005 SUPER DUTY F-SERIES/EXCURSION - THUMP NOISE FROM THE PASSENGER BULKHEAD AREA WHEN THE ENGINE IS STARTED
SOME 1999-2005 SUPER DUTY F-SERIES AND 2000-2005 EXCURSION VEHICLES EQUIPPED WITH A/C MAY EXHIBIT A LOUD THUMP NOISE FROM THE PASSENGER BULKHEAD AREA WHEN THE ENGINE IS STARTED. THE SOUND IS CAUSED BY THE FRESH AIR DOOR CLOSING WHEN VACUUM IS APPLIED TO THE FRESH AIR DOOR SOLENOID. THE SOUND CAN BE ELIMINATED BY SWITCHING THE CLIMATE CONTROL TO THE OFF OR VENT POSITION BEFORE THE ENGINE IS SHUT OFF. THIS IS A NORMAL CHARACTERISTIC, SO DO NOT ATTEMPT REPAIR.
EFFECTIVE DATE: 11/19/2004 


15697 NORMAL CONDITION: MOMENTARY GRUNTING SOUND
SOME VEHICLES WITH AIR CONDITIONING UTILIZING R-134A MAY EXHIBIT A MOMENTARY GRUNT/POP AFTER BEING PARKED FOR SOME TIME & THE COMPRESSOR IS ENGAGED BEFORE THE ENGINE COMPARTMENT HAS WARMED UP. THIS IS DUE TO LIQUID R134A BEING PUMPED OUT OF THE COMPRESSOR. R134A WILL TRAVEL TO THE COOLEST POINT (THE COMPRESSOR) ONCE THE ENGINE HAS COOLED, DUE TO THE DIFFERENCE IN TEMP BETWEEN THE ENGINE COMPARTMENT & THE VEHICLE INTERIOR. WHILE MANY VEHICLES HAVE PCM STRATEGIES THAT ADDRESS THIS BY REPEATEDLY CYCLING THE COMPRESSOR ON START- UP, THIS MAY NOT TOTALLY ELIMINATE IT. REPLACING A/C COMPONENTS WILL NOT ELIMINATE THIS. COMPONENT DURABILITY IS NOT AFFECTED. MINIMIZE THE NOISE BY TURNING THE A/C SYSTEM TO VENT BEFORE EXITING, & IN MILD AMBIENT TEMPS (APPROX. 50-75F) WAITING A FEW MINUTES BEFORE TURNING ON THE A/C OR DEFROST.
EFFECTIVE DATE: 03/06/2002


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## Jay brown (Dec 26, 2005)

thanks, always wondered what that was


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