My girlfriend's 1997 Contour suddenly started making a rattling noise when she starts it. It's pretty damn loud. I thought it was a grinding at first, but it's definitely a rattle, and not a knock. We both know very little about cars and she doesn't have any of the owner's manuals.

We weren't able to track down where the noise is coming from, but we -think- it sounds like it's somewhere low, near the right side of the engine (right side when looking at it from the front).

Any ideas on what the problem could be? Is it something loose that I just need to tighten with a ratchet or am I being way too damn hopeful? :wink:

Bonus question: She got the AC replaced a year ago, and when summer came around, we realized it didn't work. We figured it just needed more refrigerant, but when we asked our friend to help refill it, he says that the AC isn't even working in the first place. Since we lack the manuals, which fuse would we want to check? And, if it does lack refrigerant, where would I expect to find the "low service port"?

Well...since no engine or transmission type was mentioned, I'll just assume you have the V6.

Assuming you have the V6, it's probably a rod knock.

Yea, it's a V6. My friend came over and had a look, so we checked one of the pulley systems (the water pump pulley, I believe). The small pulleys didn't feel loose at all, so he assumes it's the large metal part further down. Anyway, we removed the belt briefly to see what would happen, and we ended up with the same rattling. After turning off the car, it started making the ignition noise. Not actually starting up, but that wheezing noise your car makes when it won't start. After some fiddling around, we got it to shut up.

Then when my friend was checking the pulley, the car suddenly attempted to start again, even with the keys out of the ignition. The pulleys also started moving during this process (scaring the hell out of my friend, naturally). At that point, my friend knew he was in over his head, disconnected the battery, and we called it a day. He has a friend who works at a Ford dealership, so he might be coming over sometime soon to check it out. Just figured I might as well update the situation here as well.

Could a bad alternator be responsible for the car starting on its own AND whatever the rattling sound is?