2000 Chrysler Sebring Fam belt wrapped around crank shaft

Hi krbrat. Welcome to the forum. By "back belt" I think you're referring to the timing belt. Yes, what you described can happen but it is more common on other car models. This IS common on the Ford Contour / Mercury Mistique, for example. To prevent very costly engine damage, your timing belt should probably have been changed long before 131,000 miles. Your engine is called an "interference" design. That means the open valves and the pistons occupy the same space but not at the same time if the timing belt is working properly. Had your mechanic not noticed or looked into the cause of the knocking, you would have been stranded on the side of the road when the belt broke completely, and repairs would have likely cost over $2000.00 for a valve job.

As for the oil leaks, have the PCV system checked to be sure it isn't allowing excessive pressure to build up inside the engine. That could force oil to leak out.

Thinking back, I might be wrong about your engine being an interference design. The four cylinder engine is but possibly not your V-6. If it is not an interference design, a broken belt will still leave you stranded, but all that is needed is a new belt, and usually a new water pump for insurance since it is one of the pulleys the timing belt goes around.

Caradiodoc

Oh. Happy to hear the timing belt was already changed. I incorrectly assumed you meant the timing belt was wrapped around the crankshaft because you said they removed the timing cover, but a serpentine belt can do that too. It's unusual they had to dig in that far to find the belt but it's good that's all it was.

As for running poorly, was it doing that before the belt service or did it just start when they worked on the car? If this just started after the belt service, have them recheck their work. A vacuum hose that inadvertently got knocked loose, especially to the MAP sensor, could cause poor running. I just solved an identical intermittent problem on my oldy moldy '88 Grand Caravan with a V-6 engine. Like yours, it would barely stay running when trying to accelerate, but it acted up so seldom, it took 11 months to finally fail completely so I could troubleshoot it. Turned out to be a shorted ignition coil. Funny thing is, all of the symptoms could be rationalized as to why the coil could not be the problem. Your engine uses an ignition system very similar to mine but there is nothing anyone could have done to cause a coil to go bad.

There could be a sensor problem too but the Check Engine light should be on indicating the Engine Computer detected the problem and recorded a diagnostic fault code. Not all codes result in the light turning on but that should happen when the engine runs that badly. Your mechanic can read any codes if they are present. They will indicate the circuit or system with the problem, not necessarily the defective part. Many auto parts stores will check for codes for you too at no charge. Regardless if there are codes or not, your mechanic can also connect a computer, called a scanner, to the car to view live sensor data while driving. When the problem is intermittent, many scanners have a record function that will allow him to record about five seconds worth of information that can be studied in detail later.

Caradiodoc

I agree that does sound strange, but I've seen some really weird stuff on my own vehicle the last two weeks. I'm going to research your engine because I couldn't remember if it was an interference engine, but in the meantime I can share some information about the four cylinder engine.

They use a crankshaft position sensor on the back of the engine and a camshaft position sensor on the driver's side of the cylinder head. The crankshaft and camshaft are the two parts that must be in perfect unison to prevent the valves from hitting the pistons. If something happens that causes the cogged timing belt to jump one tooth, the Engine Computer will see the two signals from those two sensors arriving at different times. It will set a diagnostic fault code, "cam and crank sync" in memory and turn on the Check Engine light. Horsepower will suffer but you might not notice it so much at highway speeds.

If the timing belt jumps two teeth, the computer shuts the engine down by turning off the power feeding the injectors, fuel pump, and ignition coil(s) / spark plugs. It does that to protect the valves. If the belt jumps three teeth, ... Well, that's when the bad stuff happens. I would be more inclined to think it was a piece of timing belt that was knocking but it's impossible to say when I can't see it. The fact that it's been replaced already suggests I'm wrong, but regardless, if something got in there and made noise, that proves the engine was running, and if it was running, the computer hadn't shut it down, and that means the timing belt could have only been off a maximum of one tooth, if even that much, and that means the valves should not have been damaged.

I CAN suggest that sometimes you don't get a straight answer from the mechanic, especially if you're in a bigger shop where translation is lost between the mechanic who knows what is wrong and the service adviser who isn't a mechanic but understands how to talk with customers. The miscommunication is not intentional, rather, they "dumb-it-down" so customers can understand it, but then they sometimes get caught in what appears to be a lie or deception when the customer actually knows more about cars and how they work. Here in my town we are very lucky to have a whole bunch of very reputable shops, but we have a few rip-off artists too. Everyone in the repair industry knows which ones those shops are, but a lot of people think they're the best places to go because the lies they were told didn't sound like lies. One way to spot a reputable shop is the people there will rarely speak negatively about a competitor.

Getting back to your engine, the camshaft position sensor is inside the distributor, and the distributor is driven by the camshaft, so the computer will still detect signals that are out-of-sync. One of the things every mechanic dreads is new problems that show up while the car is in his possession. There really isn't an easy way for the mechanic to CAUSE the problem he said he found, in fact, it would take a real lot of work to damage something, even intentionally, so I have to think this problem was going to happen anyway. That doesn't make it any easier to accept, but I agree it does sound fishy.

By the way, there are two models of Sebring. Do you have the convertible model which is a twin to the Stratus and Cirrus, or the LXI model which is a twin to the Dodge Avenger? The radio display is orange on the LXI model. I think they use the standard bluish-green display on the domestic model.

Caradiodoc

Hmmm. I only have a '97 service manual but the engines should be the same. I can't find any reference to the V-6 being an interference engine. That's probably why I haven't heard any horror stories about bent valves. I don't see the cam / crank sync fault code listed either, then it occurred to me that with a distributor, it can be adjusted, or misadjusted to mimic a jumped timing belt. That would cause the computer to shut the engine down, ... Which doesn't happen. All that adjusting it will do is change very slightly when the fuel is squirted from the injectors. You will never notice that as far as engine performance is concerned. The fact that this doesn't cause engine shutdown suggests the computer isn't too concerned with precise timing that is required of an interference engine. What all of this means is until one of us is told differently by someone who knows for sure, I think your timing belt can break or jump a few teeth without causing other serious engine damage. Wouldn't that be nice?

Caradiodoc