zerk16

Hey guys, ive been all over google trying to find the cause to my problem but ive had no luck. So i have come here to see if you guys can help me!

Here is my problem.

The first week that i had my new '08 GT i once heard this sound best described as a "thud" or a deep "pop" sound that came from under the hood on the drivers side when i started my car (happens around 15 seconds of turning on the car but always varies in time).
It sounds as if someone is slapping my car even though no one is around, and i can actually feel it in my seat. It happened a few more times that month and then went away for awhile, maybe happening once or twice. I figured it was happening because of all moisture where i live and how cold it can get in the mornings (i basically live about 30 minutes south of San Francisco on the beach) and so sometimes maybe the car just made some kind of sound due to all of that water in the air when i first start it up.

Anyways, it went away for quite awhile

Then ~16k miles later, its been happening again (i am now @ 18k) but more frequently. I would say 5 days out of the month it happens, so i guess once a week every week!. I am growing concerned becuase i cannot figure out what is wrong (if anything is wrong) with my car because it ONLY does it when i first turn on the car, this never happens in any other circumstance.

I just assume cars should not make that sound, it doesn't sound right.

So basically, i am hoping someone can shed some light on my problem, i love my Pony! But i don't want to take it to the dealership since it is very hard to replicate on demand.

I have a few theories.
1. It is from my power steering since the sound seems to originate from the front left wheel
2. Maybe a hose has too much built up pressure in it and when the pressure is released it is flexible enough to physically whip something under the hood, or is hitting the hood itself.
3. Maybe the GT pony engine cover is popping off and hitting my hood. Only problem is i can't tell if that is it because i think one time i looked under the hood when the sound happened only to find the GT engine cover still properly attached. - Cant remember very well.

Thanks!

Nuke

I'll have what he's drinking...

Seriously, that just sounds too weird. I can't imagine what that is, especially being that it's so intermitent.

JustCallMeSlip

Sounds like a tough one to me. Maybe it backfired through the intake. That wouldn't be good. Does the car seam to run good otherwise?

07torchredgt

I must be drinking it too , because it has been happening to my car ever since new.

The way you described it is 100% accurate.
Its intermittant, it only happens once and a while, and happens within 5-20 seconds of starting the car.
Its a loud muffled pop, from the front drivers side of the vehicle and it certainly can be felt in the car seat and wheel. It almost feels like a release of tension \ pressure due to the way it "pops" and shakes the chassis. Its noticeable enough that a passenger has noticed and asked "wtf was that". I havent had any other issues with the car, or any other symptoms, so i assume its harmless. But it is strange, and i would like to get to the bottom of it.

The car is a 2007 Mustang gt with the 5 speed. It has 20 000 km.

GeritGoul

Yoo dude im haveing the same thing happen to my car also..Scares the crap outta me everytime i hear it..for me its like someones under the hood and just hits the shizz outta your motor with a hammer and then i feel a slight movement

GeritGoul

wait a sec..duno bout you but it only happens when i first start the car for the day when its a cool engine...maybe its something expanding and contracting with the temp? ?

zerk16

ahhhhh im so glad it happens to other people! too bad we still dont know why, haha.

Yea this is only happening when i start my car. It never happens when accelerating, decelerating, braking, or simply driving.

BTW, The engine cover im referring to comes with the GT appearance kit. Its just a piece of plastic with a mustang pony symbol (like the one behind the rear view mirror) and it is kinda flimsily clipped to the engine lol. It's cool though, i like it.

and like one guy said it definitely hits loud/hard enough when it happens for passengers to notice and even feel it. It scared the **** out of me the first time it happened and it scared the crap out of my girlfriend (lol), she thought someone hit our car. Anyways ill keep checking here to see if anyone can shed some light on this.

oh and i just remembered one time it happened twice in one day, the second time was when the engine wasn't cold either. But that has never happened since then.

zerk16

yea the car runs great.

Oh, while im here, does anyone know if the 15k check up is really all that important? Ive already done most of the things on the checklist in the service manual that comes with the car. Only thing i haven't done i guess is lube the bearings and swap the tires. I just got my dealership discount for it to but they were 2k miles off, lol

Nuke

My '07 is a manual, has the Pony cover over the intake and has over 27,000 miles and I've never heard or felt that. Plus, I've been on the forum for over 1 1/2 years and hadn't heard that before. I'd really be interested to hear an answer.

Daryl06

Thank you for the enlightenment. My car also suffers from the clunk or thump that happens rarely. I thought maybe it was my exhaust expanding. But there is no way to repeat this noise on command.Thanks again.