Hey folks,

Not sure which section to post this in, so here I am hoping you will have some thoughts.

My recently purchased 1992 F-150 V-8 is in nearly pristine condition. I literally bought it from an older lady who didn't do a ton of driving/hauling but took really good care of it. My husband knows cars/trucks and thinks we got a very sweet deal, as do I.

However, after you've been driving for a bit and the truck has gotten to the warmed-up stage, we often hear a sudden, loud sound, which the first couple of times I thought was a rock hitting the windshield -- it sounds EXACTLY like that. We have since realized that the sound seems to come from somewhere on the passenger's side, seemingly inside the dash (but likely in the engine compartment). My husband thinks it is just some metal expanding somewhere and nothing to worry about, but man, it makes me jump every time and I've never heard anything like it in a vehicle.

Any thoughts on what this might be, and should I worry/do something?

Many thanks,

Susan in BC

 

my dads old 95 bronco had a similar sound but his was a loose/missing bolt that held the dash. how loud is it? does it do it under normal driving conditions? while on a rough road? accelerating? braking? cruising? idling?

 

Hi Matt,

It happens under normal driving conditions, generally when we are accelerating or at cruising speed, I would say. It only happens once, usually about maybe 10 minutes after you start driving. I would think if it was something loose, you would hear it rattling constantly or more than once, anyway, no?

As for how loud, it is pretty loud. It sounds exactly like what you would hear if a good chunk of gravel whacked into your windshield at high speed. One big, loud smack. Really weird!

 

make sure it aint just the a/c compressor clutch engaging and disengaging.

 

Hi Matt,

It doesn't seem to happen in any relation to the air conditioner. It will happen whether that is on or not, and I can hear the compresser clicking on and off when the A/C is on, and there is no sound like that.

 

alrigt just wanted to make sure. alright so its coming from the passenger side while accelerating and cruising right? and its only when its warm. is it only one smack every so often? or is it a constant smacking noise as soon as it starts to do it?
if its a constant smack- maybe exhaust leak. does the gauge show oil pressure?
check the fan shroud sometimes they break at the bottom and shift position which can sometimes cause a constant smacking noise, sometimes an intermittant smacking noise, and sometimes a rubbing noise.
does it matter how fast you drive? or how hard you accelerate?

 

Hi Matt,

It will only happen once during a drive, about 5-10 minutes after you start the truck. You won't hear it again during that drive. It doesn't seem to be connected to when you accelerate -- it just happens out of the blue, one time, BANG! The first couple of times I really thought a piece of gravel must have smacked my windshield. Then, when I noticed it kept happening pretty much every drive, it became clear it wasn't that.

It is definitely not a series of sounds or an ongoing sound. Just that one solitary loud noise, then nothing again until the truck has been turned off for a while and started up for a while again.

 

ok i have no clue then. IMO nothings really wrong. if it gets worse then you can worry but i wouldnt worry right now. could even be a rock being picked up by the tire and thrown at the truck.