I have a 2008 Dodge Avenger with 2.4 liter 4 cylinder engine and 4 speed automatic transmission. Odometer reading is 80750 miles. Engine has developed over the last several weeks an ominous noise from the valve train. This engine has a chain driven exhaust camshaft and intake camshaft with variable valve timing. Both when the engine is cold and after warm up there is a very noticeable noise coming from the crankshaft pulley head of the head. It definitely sounds like it is coming from the camshaft drive area. At times it is a whirring noise, some knocking and occasionally some popping in this area. It is even noticeable from within the cabin area when driving at slower speeds of 10 - 20 mph.
I removed the serpentine belt accessory drive and turned all the pulleys. The belt tensioner pulley was making noise so I decided to replace 2 fixed idler pulleys and the tensioner pulley. Noise level is still about the same. So I decided to run the engine without the accessory belt in place. Good news. The noise is not present. So my idea that there was a problem in the valve train is wrong.
So the issue is how to determine which accessory is creating the noise. I turn the water pump, AC compressor shaft, power steering pump and they all seem smooth. I am leaning towards the power steering pump since that has internal rollers that move along an oval track inside the pump. The water pump only has an impeller and a bearing and the alternator just has slip rings and bearings. Any thoughts on how to accurately determine which accessory is creating the noise?
I removed the serpentine belt accessory drive and turned all the pulleys. The belt tensioner pulley was making noise so I decided to replace 2 fixed idler pulleys and the tensioner pulley. Noise level is still about the same. So I decided to run the engine without the accessory belt in place. Good news. The noise is not present. So my idea that there was a problem in the valve train is wrong.
So the issue is how to determine which accessory is creating the noise. I turn the water pump, AC compressor shaft, power steering pump and they all seem smooth. I am leaning towards the power steering pump since that has internal rollers that move along an oval track inside the pump. The water pump only has an impeller and a bearing and the alternator just has slip rings and bearings. Any thoughts on how to accurately determine which accessory is creating the noise?