Buick Repair Questions? Ask a Mechanic for Answers ASAP
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Does this knocking increase with engine speed when revved up and is it a loud knock or a tick rattle type noise?
Let me know so we can continue,thanks Pete.
O.k.,does the noise speed up at all with the engine speeding up or does it remain the same?
O.k.,there is a good chance this is a lower rod bearing or main bearing failing on the crank shaft.This was a common fault unfortunately for this model here.Coolant may have got down into the engine oil and damaged the bearing as this is common with head gasket replacement or if this model had the dreaded upper intake coolant leak that caused engine failure.
One other component that can cause this is the engine harmonic balancer/crank shaft pulley coming apart internally.I have seen this fail before and had to replace it as well for this type of noise here.
Unfortunately without seeing and hearing the vehicle it is difficult to say for sure from here which of these is the cause.This will have to be inspected most likely by a repair center to locate the cause and then determined what caused it.If found due to the head gasket replacement I would speak with the repair facility that did the head gasket replacement to see if they will cover the costs for repair for this here or help with the costs.
If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.
It can be the main bearings on the crank or wear on the new rod bearings if the crank had any scuffing when the new ones were installed last.The crank bearings are a common issue on this model here for this fault as well as the harmonic balancer.This will have to be checked further to pinpoint and repair this issue here.
Let me know if you need anything else and feel free to rate my help here.Thanks Pete