I remember someone posting about this a while back, so if anyone remembers, let me know. About 5 seconds or so after I start the engine, there's this single pop, or clunk that comes from the engine compartment. It's not very loud, but was loud enough to hear it. It only started this in the last day. It happens every time I start the truck, but it has to sit for about a minute or two to repeat it consistently. It seems to be coming from the a/c compressor area, just like the person who posted this before. Is this a sign the compressor is about to go out?? Help me out if you can.,,,,,98

 

It's the guy next to you... he hears your truck after you start it and hits his head against the steering wheel of his chevy and says "should have bought a Ford." Then he stares and drools for a minute, comes back to sanity and begins repeatidly hitting his head on the steering wheel.

Actually, I have no clue what it could be. Anyone know?

 

My truck makes the same noise. Dealer said it was normal something about the oil in the compressor. " cold start noise they called it."
The A/C forum had something on its. Do a search it there.

 

Occasionally I will get the same noise from my truck at first start-up. I noise seems to come from the right front engine compartment and it only happens one time and not very often. I suspect it has something to do with the compressor (I always leave my AC in the on position even at start-up). The noise doesn't seem to have any negative effects with it so it's just one of those quirks that one lives with.

 

OK, not trying to insult anyone. But are you SURE its not the AC clutch engaging?? Does it sound like it or is it different? Just asking since you said you leave the AC switch on. I read somewhere that you should always kill the ac before you kill the truck so help prolong the life of the ac. Don't know why, but i always have.

 

I also have a 'pop' sound that happens shortly after I start my truck. It sounds like it is coming from behind the glove compartment. The sound is like a plastic box or panel popping out ( kind of like when you put a cookie sheet in the oven and it pops when it heats up).

 

Exactly!! That's the noise I'm talking about. Sounds like a baking pan popping into shape in the oven! I tried a start with the a/c off, and it didn't do it?? So, I guess it is something to do with the compressor?? I'll try the no a/c start again today to see if it does it. It may be a cold start issue for some, but mine does it every time it sits for more than two minutes I'll let you all know if it does it on the no a/c start this morning. I also listen for it when I turn the a/c on after a minute or two of driving,,,98

 

I've had the same noise from time to time from day one when I bought my truck new... I have no idea what it is, as long as everything else keeps working corectly I'm not worrying about it!

I belive it does have to do with the AC compressor though. I turn my AC off before turning the truck off, and never hear it with the compressor off. Occasionally, when I start the truck up and turn the AC on, it will make the same lound popping noise your talking about.

 

98screamer, The noise is probally caused fom oil in the a/c. Its pretty common and Ford has had a few TSBs concerning this although most of them were on the 250-350. Drain a little oil or replace your accumulator and it will probally fix it. It shouldn't cause any problem, I've heard some so load you thought the dash was going to fall out, think of it like draining the water pipes in your house, when you go to turn your water back on you would swear the pipes are comming through the walls due to the air and water comming through the pipes. What you are hearing is oil hitting the dryer and evaporator.

 

It's pretty wierd that it would wait 80 thousand miles then start all of a sudden Oh well, nothing I can do about that. The accumulator is a pressurized part, right? Just what I need with a somewhat expensive mod coming up next week,,,,98

It doesn't do it if the a/c is off when you start it, or if you turn the a/c on after it's running. Hmmmm. Guess I'll just turn the a/c off when I shut the truck off from now on

 

If you get in, shut the door, and turn the key to the run position, it makes the same noise. ( Have the windows open first )

Almost like a dampener in the HVAC system moving.

I usually only have my HVAC control in the floor position, which I thought was without the AC running ( the manual says to leave the HVAC **** in any potion but off or MAx AC (?) so the vents are open when you shut off the motor. This allows outside air to get into the cab.

There is a hiss noise and then the clunk, all this without the engine running.

I just checked this again, don't even need the engine running to hear it.

It sounds like it comes from the front pass side ( both the hiss and the clunk ), so it could be the AC, but without the engine on, and the HVAC control in the off position, I don't know how the oil in the AC is causings this, nor do I know that it is not.

Try it without starting the engine, and you'll hear the same noise.

Now for what it is ........go figure I'm out

 

I've heard that millions of times, this just started yesterday. It's hard to describe really. Something like hitting a piece of thick metal with a ball peen hammer. I tried looking at the a/c compressor and belt tensioner to see if either of one of them was making it, but couldn't actually see anything happening. It's definitely under the hood, but you can hear it through the passengers' side dash. Wierd!!,,,,98

 

Sorry about that, I confused the hiss-clunk with the hammer to metal clunk

I thought I was hearing the same thing...guess not, it is a differenet standard noise...

 

LOL,,,,98

 

Yea, that really doesn't make sense that it would all of a sudden start after 80 miles. Have you had any a/c work lately or maybe just an a/c service. Whoever did it could have added oil. Maybe it the fact thats its been really hot lately. Judging by your symptons it sounds like like the a/c noise I talked about previously it just doesn't make sense that it would all of a suden start.