Engine problems

I have a 2001 Plymouth Neon and I believe I am having engine issues. While sitting idle, it sounds normal, but, while driving, I hear what sounds to be a groaning sound coming from the engine. I recently had an oil change and there are no leaks. It does not overheat and the cooling fan works. What could the problem be?

I think we need more info about the sound. To hear such sounds more clearly, drive along parallel and close to a a wall (like at the back of a shopping center or industrial park) with the windows down. You might be able to isolate it to being louder on one side, vs the other - or being directly in the middle. You might want to try driving backwards and see if the sound is the same. If you have someone who is mechanically inclinde to ride with you, it can be a good diagnostic tool. And see if it gets louder when you open the throttle, or drive in first gear.

i think that would be a good idea......usually when i am driving, its near a concrete barrier on the highway and i cannot tell where its coming from. i will try that. thank you for the advice.

Ok, I cannot really tell too much which side the noise is coming from, but, I do have a better description of the noise. I notice it more when I am slowing down to go around a bend, or to come to a stop. It reminds me of the noise semi's make when they use their engine brake, but not quite so loud. I hope this is helpful!!!

I have had that same kind of noise, for different reasons on different cars. I think of the sound of the Jacobs Brake on an 18 wheeler as a sputtering growl.
1. First check that your lug nuts are snug on both front wheels - in fact check the back wheel lug nuts too. If you find that they are not snug already, the sound might be the inner side of the wheel rubbing against the disc brake caliper. If this is the cause, it will get worse unless you tighten those wheel nuts. If you find them loose, check and retighten them again in about 25-50 miles to make sure you got them tightened, and again about 150 miles after that. You dont have to over tighten them - just be sure they arent loose. If it IS a loose wheel, it will eventually be making a low growling noise while driving at steady speeds - louder as you go faster; because it will work 'looser'. It can ruin a wheel.
2. You might have a disc brake caliper that isnt properly bolted at both ends, i.e. the upper bolt and the lower bolt not tight. And it might have shifted enough to be rubbing the inner side of the metal wheel rim. A close inspection of the caliper (with the wheel removed) would show you a small bright spot where it rubbed - while the rest of the caliper is sort of rusty. If you have the wheel jacked off the ground, it might not make the noise at all.
3. It could be the black plastic inner fender liner has come loose and droops onto the tire when you are slowing down. The front of the car dips when you brake, so it might not touch at steady speeds. These inner fender liners are a soft plastic, easily damaged by clumps of ice. But it wont hurt the wheel by rubbing on it - it would just be an annoyance. This could involve either wheel.
4. Very Much Less Likely, but still possible: If you had the CV joints or axle shafts worked on lately, and someone didnt get the big hub nut (its in the center of the front wheel)torqued enough (like 150-200 lbs-ft!), it could be the hub has worked loose enough to let the wheel touch that brake caliper.
5. Very rare, but it still happens: A bad wheel bearing on the front could be letting the wheel sag and rub that brake caliper. This is really rare, but if the car has been driven in water deep enough to be over the wheel bearing - it could have gotten wet, rusted, and is now letting you know the bearing is going bad. This could cause a soft moaning sound at speeds above about 30-40 mph.
If the sound changes directly with changing car speed, it could be one of the above. I have had each of these problems in my time. If the sound doesnt keep pace with car speed, look underneath and see if one of the pieces of black plastic underneath the front of the car are coming loose and drooping down, or even rubbing a tire on turns.

Thank you, I will take all of this into consideration, but, the sound gets louder when I slow down to stop or go around a bend, and is pretty steady when driving at one speed, not when driving faster. Is it really possible that the lug nuts come loose on their own???

Lug nuts will not come loose on their own - IF they were tightened in the first place. If someone changed a tire, and didnt finish tightening the lug nuts - they can work themselves loose enough to make noise, usually in the first 100 miles or less.
If you havent had the wheels worked on during the last 200 miles, then they would not be coming loose.

Still, I check the lug nuts on a vehicle before we start on any long drive in it. My wife was going to drive about 200 miles today. I checked the lug nuts, which were all okay, then checked the tire pressures. One rear tire was low (16psi), and I know they were all 32 psi about 4 weeks ago. So I changed to an extra wheel we keep on hand, and checked those lug nuts a second time. (The tire I took off had a small screw stuck in it. It will be easy to fix, since we didnt drive on it while flat).

Another possibility is the engine mount. A number of posts in the forum note the poor quality of the engine mounts, especially the 'hidden' mount. Over time, the rubber wears out/dries out, and then the bolt for the engine starts rubbing on the mount. It is usually more noticeable at certain engine speeds, due to the vibration being more likely to cause noise at those certain speeds. Thankfully, there is little danger in this situation. It is simply noisy and annoying.

I don't think he cares now. This post was started 5 years ago.