Metallic rattle near the alternator

2003 Dodge Caravan Sport has a metallic rattle near the alternator. It gets louder when it is in Drive or Reverse and you have your foot on the brake. Also, it gets even louder when having your foot on the brake in Drive or Reverse and the heat or air is on. My husband thought it was the power steering pump so we replaced that but it didn’t fix it. If anyone has an idea of what my be wrong, please let us know. We are on the verge of trading it in because we have no idea what could be causing it. Thank you.

Did Your Husband Run The Engine While The Belts Were Removed When He Was Changing The P/S Pump ?

That would tell you that the problem is inside / outside the engine.

I’d use an automotive stethoscope (available Sears or auto parts store $10 - $15) or a length of hose to listen to different components in order to isolate the noise.

The fact that the noise is louder with A/C or heat (particularly on “defrost”) suggests the problem is in the air conditioner compressor. In fact, Chrysler’s got a bulletin for their technicians to help diagnose bad compressors that have failed due to poor lubrication on some 2001 - 2003 Caravans.

However, to keep guessing and “throwing parts” can prove to be penny wise and pound foolish. If your husband can not find the problem with certainty then you would be ahead of the game to pay a competent mechanic.


It could also be as simple as a tensioner or idler pulley. When you turn on those items, they’re pulling more power, making the alternator work harder. Thus, the belt tension changes, forcing more pressure on the tensioner.

However, as CSA said, a stethoscope is a relatively cheap and efficient way to isolate those peculiar noises.

I’ve used a length of solid metal (I like my breaker bar for this) to listen to areas, too. Merely press it up against a metal part and your ear. It tranmits the sound directly to your ear.

Caution: Be very careful when working around a running motor. Belts can snag clothing and hair, and anything you put near them can be taken from you and thrown at you or someone else.

I appreciate the help from CSA & chaissos. My husband did take the belt off and we cranked it up. The sound wasn’t there anymore, so we now know its not in the engine. He took a pipe and held it up to his ear and he said that the sound seemed to be coming more from the back of the motor in that direction. If you have anymore advice, please, it is very welcomed.

You’re looking at a bad pulley or belt tensioner. Its an '03. If its got the original tensioner it wouldn’t be a bad thing to replace either way.

Since the problem has not yet been identified, with the engine running check each end of the alternator with the blade of a very long screwdriver against the alternator housing and the other end of the screwdriver against your ear. Could be a failed alternator bearing.

Thank you cigroller. My husband is thinking about replacing it. I do believe it is the original tensioner, because it had 71,000 on it when we bought it and now it has 138,000. We haven’t had to do much maintenance on it at all. We have only done regular maintenance, replaced thermostat, power steering pump, new belt, replaced spark plugs & spark plug wires, and a new starter.

When a belt is replaced, ideally, the tensioner should be replaced at the same time. It’s cheap insurance against a pulley seizing and tearing up the belt. Idler pulleys should be considered, too.

Best of luck…