Rough sound on cold start

Greetings everybody!

On cold starts (in the morning, when I'm going to work and in the evenings when I'm coming back home) I hear a kind of rough sound.

The sound is:

1. NOT high pitched
2. Is close to a rattle, but doesn't sound like something is necessarily loose.

I don't hear it after driving for about a minute or so.

It is less pronounced if I allow the car to warm up for 2+ minutes than 1 minute.

Recent work done on the car:

1. Had the entire timing belt assembly changed (including the water pump, thermostat, etc.)
2. Transmission flush.

What do you think this sound could be?

Thanks for your help!

my car doesn't start up with a rough sound, but if I start driving before its warm it sounds like crap. I have to let my car warm up for a good 20 minutes before I can go anywhere, otherwise it just sounds bad. Back home we didn't get as cold of temps as here (used to live in WA until a few months ago and just moved to NJ) and so I never experienced this problem before. But ever since it began freezing here I have. At my old place I also had it under a big carport and next to the house, so the car never got like freezing cold. Here it sits out in the weather since I don't have a carport or garage.

I have no idea what causes this noise on my car other than the cold, but I do find it really weird.

A car is like a person...in the morning when you get up, not everything works 100 percent. But you grab your coffee, and a powerbar, and you are good to go. The car is the same way...in the cold it just needs a little time to get up to snuff. As long as the sound eventually goes away after its warm, there is no problem. There are a lot of fluids that make noise in the cold, your power stearing screams when you turn the wheel the first couple times...but we all know it's going to happen. After shes running for a little, all the fluids are up to temp, your brakes are getting warm, your power steering is movin....eveything is fine. In cold weather you just have to expect your car to sound like shit until its warmed up. That clicking sound you hear might just be a belt that needs to get warm, or your oil running a little thick at startup. As long as the sound goes away you have nothing to worry about.

Thanks for your replies!

The sound does go away shortly after I start driving. So if it's just a warmup condition, that's great. The night time temperatures here have been around 42-50 F (which I realize is not cold at all, going by the current temperatures in most of the country now.)

I guess I'm a little paranoid because it appears that my old timing belt, which was making a flapping sound on start up as well, was extremely loose and the mechanic I took it to said I had been very lucky that it hadn't slipped off.

Yeah usually my Eclipse is garage kept. But one night I left it outside. That night it had got down to 9 degrees. When I got in the car it was making a bunch of different noises I was use to. The car was also stiff and didn't even feel like it wanted to turn. But after everything warmed up it was fine.

You can use lucas oil is a very good option, you will notice the diference.

on the brakes warming up part. If you sit there for like 20 minutes to let the car warm up before driving it, will that warm up the brakes also or do the brakes have to warm up as you use them after you start driving the car? A friend of mine almost slid her car into a semi b/c her brakes were still frozen. And since this is my first winter here where it actually snows and gets low in temps I'm afraid of doing something like that. So do the brakes warm up also while the car is warming up in the driveway?

on the brakes warming up part. If you sit there for like 20 minutes to let the car warm up before driving it, will that warm up the brakes also or do the brakes have to warm up as you use them after you start driving the car? A friend of mine almost slid her car into a semi b/c her brakes were still frozen. And since this is my first winter here where it actually snows and gets low in temps I'm afraid of doing something like that. So do the brakes warm up also while the car is warming up in the driveway?

no, the brakes will only warm up from use. they will not warm up as the car warms up.

that's why stick shifts are useful, engine braking and if your going in reverse and need to stop, use first!

i've not heard of lucas oil

lucas oil is an aditive

They make oil and fuel stabilizers. Out of curiosity, has anyone heard/used that stuff called Z-MAX? If so, did you notice anything?

If you guys are talking about cold...Omaha Nebraska has been quite the freezer of late. I think last week we were getting regular temps of -10, and like -25 windchill. And it's not even the worst part of winter here yet. Now, that is brutal on startups...almost makes me want to invest in a block-heater.