My car has a clattering or ticking noise?
There are multiple things that can cause a rattle or ticking noise to happen on your vehicle. Today we’re going to talk about a rattling noise that has become very common on Dodge 5.7L Hemi engines. This truck came into the shop and had a complaint of an intermittent rattle or ticking noise. The noise wasn’t super loud and wasn’t rattling consistently however every two minutes it would have a slight clattering sound when idling. A stethoscope was used to pinpoint the location of the noise and found the noise was most prominent at the valve cover.
Inspection Process:
Now that we have narrowed down where the noise is coming from, a more intrusive inspection is needed. We know the clattering noise is coming from underneath the valve cover and at this point the valve cover needs to be removed for a visual inspection of the camshaft, push rods, & roller bearings. Once the valve cover was removed, we found excessive wear on the camshaft lobes as well as the roller bearings. Upon disassembly and inspection, we found a bent valve, bent pushrod, worn roller bearings, and worn camshaft lobes. After replacing the camshaft, bent valve, bent pushrod, and the roller bearings the vehicle is running like new and the clattering sound is gone!
What does a camshaft do?
The camshaft and crankshaft work directly in unison together, there is either a timing chain or timing belt that connects the camshaft to the crankshaft. As the crankshaft rotates the camshaft rotates as well, during the camshaft rotation the lobes that are on the camshaft roll across the roller bearings located inside the cylinder head and open or close the intake and exhaust valves at a very specific timing interval. Camshafts are an extremely critical timing component and are manufactured very precisely. Camshafts are made from a casted steel and are milled to make each individual cam lobe to the exact measurement needed to fully open and close the valves in the cylinder head. Camshafts have four strokes; intake, compression, power, and exhaust. The intake stroke is when the camshaft lobe is pointed directly at the intake valve being opened to allow the air and fuel mixture to enter the cylinder. The compression stroke is when the camshaft lobe is oriented in a way that the valves are closed allowing proper compression to be built inside the cylinder. The power stroke is when the spark plug ignites the air and fuel mixture inside the cylinder which forces the piston in a downward motion creating power. The exhaust stroke is when the camshaft lobe is contacting the exhaust valve and fully opening it to allow the burned fuel and air to exit the combustion chamber. When a camshaft is worn or damaged the valves wont fully open all the way causing a cylinder misfire and poor engine performance. Worst case scenario a damaged or broken camshaft can cause damage to the cylinder head, valves, push rods, roller bearings, piston, or crankshaft.
Regular Maintenance!
The camshaft surfaces are constantly being lubricated by engine oil to prevent any excessive wear from happening. It is critical that the engine oil be replaced at the recommended interval as well as with the correct oil for the engine. Engine oil is not only used for lubrication, it is also used to keep the moving parts of an engine clean. Overtime engine oil will degrade and break down, when this happens the oil will lose its lubricating properties and no longer clean the surface like it should, resulting in wear and tear on the internal engine components potentially leading to damaged parts that will need to be replaced.
Quality Repair From People Who Care!
At Dickerson Automotive we use high quality engine oils, fluids, and top of the line equipment. We have found that through regularly scheduled maintenance expensive repairs are reduced significantly, and vehicle life is extended. It is much easer and cost effective to maintain a vehicle regularly, versus fixing it as it breaks. If you have questions or are interested in a maintenance plan give us a call!
Sources:
- https://www.liveabout.com/what-does-a-camshaft-do-4165125