Noise from car: sounds like hole in muffler, but then disappears!
 

I have a '93 Ford Tempo (4 cyl).

The past 3 days, whenever I start it up, it sounds like the exhaust system towards the FRONT of the car has a hole in it or something: pretty much like it sounds when you have no muffler except at the front of the car.

The odd thing is, it goes away after 5-10 minutes of driving it. I live only a few miles from work, so whenever I start it up, it'll make the sounds, but by the time I get to work, I can give it gas while it's in park and won't hear a single thing wrong with it!

A friend of mine says it's a problem with the exhaust at the front of the car and as the car warms up, something is expanding to make a better seal or something. While that does make sense in a way, it doesn't seem like a hole or something in the exhaust system would just go away after 10 minutes of driving. I'd imagine you'd still be able to hear it somewhat.

The only thing I did recently to the car, aside from getting an oil change, was put a new radiator hose in (upper one) because my old one looked collapsed and I thought my car was overheating when it turned out that it was probably just the hot weather making the temp go up that high. In any case, the hose looked like it was in bad shape and I replaced it anyway.

Any ideas?

You could put a new exhaust gasket where the manifold meets the head. or check the donut gasket that goes between the manifold and exhaust pipe. Also check your exhaust manifold for cracks.

Sounds like the bolts holding the exhaust manifold to the head are a little loose. Retightening the bolts should help out.

Yeah, gonna go with the exhaust manifold gasket leaking, or the gasket at the joint between the manifold and down pipe.

I've had the gasket ring between the headers and the pipe go bad as well - alot easier to change that then to try tightening old, seized up manifold bolts.

When the car is cold, pop the hood and start the car. Feel with your hand around the pipes and try to feel for the exhaust leak. The pipes won't get hot for a few minutes. Stick your ear down in there to try pin pointing the noise.

Watch out for the fan when you do this!

No, no, no, you're doing it the hard way. Get a piece of 1/2" tubing from the local hardware store and put one end to your ear while moving the other around to listen for the leak. When you hear it (and possibly feel hot exhaust gas filling your ear canal since you stuck the tube inside of your ear instead of holding it up to your ear like I told you to,) you've found the problem.

Thanks a ton, I'll try this out!

Now, I know nothing about cars or where any of this stuff is located (but I'm sure I could find out easily)... is it difficult to change these gaskets you speak of?

What are the cost of the parts I'll need, and would I need any special tools?

Thanks again for the help!

I noticed a small anti-freeze leak today.

Do you think these two are related in some way?