Skip the auto shop - Our mechanics make house calls

Q: Engine rod knock

asked by on

Trading my car at the dealership & they inspected my car & gave me the value. Next day before I go to trade in my car I turn my engine on and hear a loud rod knocking. Called the dealership and explained the problem. They said since they already inspected my car, to just bring it to them and they will repair the engine. But in order for me to get to the dealership they said to use a thick oil in the engine to temporarily stop the loud knocking. What's the best oil to use for my Chrysler 300 for the rod knock? And how many quarts do I need? Thanks in advance!!

My car has 89000 miles.

A: Hello and thank you for contacting YourMech...

Hello and thank you for contacting YourMechanic. The oil to use is a thick 15/40W oil for diesels. This oil is thicker than normal engine oil and can keep an engine from knocking for a little while. If the engine continues to knock after putting the oil in, I suggest not driving your vehicle to the dealership. If the dealership will take your vehicle in for trade, they will do anything to get your vehicle to them, even if it requires a tow. I recommend having a professional, preferably a professional from YourMechanic, to come to where you are and check out the knock in your engine.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: car is not cranking, wont start.

Usually when the car will not crank but has power to other systems, the starter is a possible cause of this issue. Considering that you have had the vehicle for 9 years and never changed the battery, it is also...

Q: There's a heavy vibration under my car - is it the U-joint?

If while driving the sound "changes" when you turn the steering wheel that would point toward bad outer CV axle joint(s). If the noise is as bad as you are describing, that will probably be easy to diagnose and indeed...

Q: I have a 2011 Ford Fusion that has a tap/knock while idling. Normal for this motor?

Hi there. Typically this is normal for this engine. The design of the valve train causes this engine to make more noise than a lot of engines, but it does not create any issues. The fuel injectors tend to also...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.