Q: Why would a mechanic add a thickening agent to motor oil?

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I bought this car in August. It received its last oil change from the dealership I bought it at. I went in today to a Hyundai dealership for another oil change, and to have the starter replaced, and they informed me that my motor oil is very thick, and there is a low knowcking noise indicating a bad rod. The mechanic told me that he believes that the dealership added a thickening agent to mask the noise of the engine that could have indicated a problem in order to sell me... a 21 year old college student... a piece of shit, that now needs a new engine. They also think that the thick oil could have ruined my starter.

Could they have done that? What other reasons would they thicken my oil? What kind of action can I take?

My car has 61000 miles.
My car has an automatic transmission.

Hi there. I understand your concern. I have never seen a reputable new car dealership add anything to engine oil, especially anything to thicken the oil. The only reason that oil will gel (thicken) is from insufficient oil change intervals. Changing the oil on time is one of the most important things a car owner can have performed. If the oil change interval is consistently late or forgotten, then this is what can happen. When the oil starts to gel, the internal engine components cannot get the oil they need to reduce friction; thus the low knock you now have. Do you have receipts for oil changes that state the date and mileage of being performed on the proper schedule? What is the service history of the car? Were maintenance records available if you purchased this as a used car? Many times, car owners do not maintain their vehicles properly and simply trade them in towards a new one before major problems start to appear. Was this car purchased at the Hyundai dealer? Was it a certified preowned? There are a lot of unknowns. And engine gel (thickening) will not affect the starter; the starter most likely failed on its own. I feel that a lot more investigation to your oil gel concern is needed before any rash decisions are made without proper documentation. Unfortunately, Your Mechanic does not offer engine repair services that involve internal bearings or other major internal engine components.

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