There is a TSB out about the A/C compressor making a metalic chirp on cold startups. I havent seen one in the shop yet so Im not for sure what it really sounds like. About 90% of what comes in our dealership are 97-2000 F150s and we dont have a problem with any piston slap whatsoever. Ive owned 3 F150s with 5.4s and am very pleased. Hope you find your fix

 

This sounds exactly like a problem I've been struggling with for a year. It first happened after spraying the engine compartment out with water. Every cold morning there after, I would hear a chirping noise for about a minute and then nothing the rest of the day. I took it to the dealer and they worked on it for about a week and replaced a bunch of stuff including the cam chain cover. They ended up saying they thought it was the water pump - anyway the noise was gone. Unfortunately, next time I sprayed the engine compartment, sound was back the next morning and persists to this day. I always suspected the idler pulley as the sound eminates from that area, but heck the AC pump is right underneath.

I went to locate the TSB you refer to but all I could find was the one that follows. Is this the one you are referring to? Also, where can I get the full details of a TSB?

Thanks -

Service Bulletin Number: 983316
Bulletin Sequence Number: 747
Date of Bulletin: 9802
NHTSA Item Number: SB607481
Make: FORD TRUCK
Model: F SERIES
Year: 1999
Component: ENGINE
Summary: SOME CUSTOMER MAY COMPLAIN OF A TICKING NOISE ON INITIAL COLD START-UP IN PARK POSITION AND NEUTRAL POSITION. *TT

 

Just what do you mean by a chirping sound? I have a rattle/knock when the vehicle sits for more than two days. If I run it every day I don't hear it. It only last for a second and then you just can't hear it again. Does this sound like your noise?

 

I've heard it, planned on having it looked at when I brought the truck in for servicing next week. Mine is more of a quick clunk, only on cold startup and the A/C was left on the night before. Thanks

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99 F250XLT Supercab LD
5.4L 3.73 LS
White/Silver
Graphite interior
6 CD changer/Captain's Chairs

 

I pulled up an OASIS report on a ticket I had laying around for a 99 f150 on noise in front, and instead of a TSB it came up as a SSM, (special service message) I dont remember the number of the SSM, but your dealer should be able to find it on an OASIS for your vehicle. by the way, after reading the SSM , it was described as a thump or thud on cold startups, good luck