Sometimes, you can hear several loud noises when a Buick engine starts. These depend on the engine, but you should investigate some noises immediately. You cannot drive the Buick without further damage if you hear banging or ticking. Banging noises tell you that something is wrong inside the engine, or outside with one of the accessories. A ticking noise could be an exhaust leak or mean you are low on oil.
The harmonic balancer on a Buick is a two-piece wheel that rides on the snout of the crankshaft. The balancer, particularly in the 3.8-liter engine, tends to separate. This could happen anywhere from 60,000 miles up, but generally happens after the vehicle has more than 100,000 miles. In most cases, it is difficult to see the separation of the balancer. It separates where the rubber part of the balancer attaches to the metal part of the balancer. Sometimes, you have to take it off to inspect. It makes a banging noise that sounds almost like a rod knock. If the two pieces completely separate, you risk damaging other parts nearby, especially the crankshaft sensor.
A rod knock occurs when one or more of the rods inside the Buick engine bends or breaks. If you hear a knocking rod (the sound is a deep pounding inside the engine) immediately turn the vehicle off and tow it to a repair facility. Bent and broken rods occur for several reasons, including, running the vehicle out of oil or over-revving the vehicle. Revving up a vehicle while in neutral (neutral rev) is particularly damaging to the interior workings of an engine.
You can hear the lifters of the Buick's engine tapping when it runs low on oil. If the oil is low, insufficient oil reaches the heads and the lifters. The lifters are hydraulic and need oil to operate properly. Without oil, metal is rubbing against metal. The lifters also move the valves up and down. You should stop the Buick immediately and add oil as needed (check the oil dipstick). If you caught the problem early enough, you might avoid damage and the tapping noise goes away. If you wait too long, even with oil, the tapping noise will not go away. The heads have a limited lifespan at this point.
