TransAmWS.6

This odd noise just started yesterday morning, I went outside to start the car to leave and it cranked up fine, oil pressure, battery voltage, etc., everyhing normal. However, it was expelling a loud, constant, humming, grinding noise right under the car, sounds like it's coming from somewhere near the front of the transmission, it sounds like it's literally coming from right behind the firewall.

It definitely isn't coming from anywhere in the engine bay, like I said it sounds like it's coming from right behind the firewall somewhere, even inside the car it sounds like it's coming from the front defroster, the sound doesn't increase or decrease with RPM's either. The strange thing is though, as soon as I start driving it and it reaches a slightly warmer temperature, it just suddenly stops and everything is fine. Anyone have any guesses? I'm at a lost, I had an appointment to get some exhaust work done Friday but if this is something urgent I may have to put that on hold.

Forgot to add, it only does it after it's been sitting for several hours. Once it does it and it dies off, if you go back again and start it, even when it's completely cold, it won't do it unless it's been sitting for like 9+ hours or so, very strange.

Thanks guys.

777Shock777

iTrader: (5)

How cold are the temperatures reaching there?

TransAmWS.6

Ah man, real cold at nighttime which is when it sits for long periods of time, probably in the high 20's, low 30's, definitely below freezing.

bad_408_vert

iTrader: (6)

subscribing, i 've had it for last 2 winters also.

TransAmWS.6

Seriously? Same symptoms and everything? This is super weird.

I've decided I'm still going to follow through and get my exhaust work done Friday since the noise just comes and goes, I started it cold earlier and it was being noisy, I just went out there and started it again and it sounded normal, so I just don't know. I'm definitely going to have the shop see if they can figure it out on Friday. It's very noisy when it does it, actually sounds like air is being forced out of something near the firewall, which makes me think that it could be possibly a hose or a vacuum line or even something with the exhaust, but like I said, I'm really not sure at all. I've never come across a problem like this with a car.

bad_408_vert

iTrader: (6)

Yeah, I have the same symptoms.

I'm not sure how to get it diagnosed because by the time car is up to operating temperature, the noise stops. Do post if you end up finding out what it is.

TransAmWS.6

I definitely will, it was about 60* out here today, no noises at all from the car, this is definitely very strange.

777Shock777

iTrader: (5)

Gah I hate the cold >_<
It makes our cars squeak, whine, grind, etc....

That and it takes longer to warm up.

TransAmWS.6

Make sure everything is good with your exhaust, I had a catback installed yesterday and it turns out that my Y-Pipe was missing a couple of bolts that were supposed to keep it connected to the manifold, so the guy just threw in a couple of new bolts for me. Was real cold out this morning, went outside to start it and it didn't make any odd noises whatsoever.

stephen4036

my exhaust bangs everywhere.. if it doesnt it when its cold go start the car and leave it.. dont drive it till it warms up.. i do that with my bike all the time when its under 50 degrees.

bad_408_vert

iTrader: (6)

Transam ws.6 - That's great! I'm glad it's something simple.
It all worked out, you solved the problem & got exhaust done too.

Thanks for the info!