Skip the auto shop - Our mechanics make house calls

Q: Hear a knocking noise when car is in gear

asked by on

I have put around 1500 miles on my car since I bought it. When I bought it, I changed the oil (I put 8 quarts in). Well, after I changed the oil, I cranked the car and put it into gear, and it sounded like a hammer was beating on my fire wall. So, I put the car in park and the noise went away. It only knocks when the car is in gear, the A/C is on.

The car was at the mechanic for a few days and they are telling me the noise is normal. I went and listened to 5 other 5.0 Mustangs, and none of them made the same noise. I just got back from the Ford dealer, and they said it has something to do with the belts. But, I feel like it has nothing to do with belts because you can hear the knocking inside the car. Outside the car, you can also hear it and it seems to be getting louder.

I'm using Motorcraft 5W-20 synthetic blend in the car with a Wix oil filter. I can put my hands on the valve covers and feel it knocking. If this has something to do with the A/C drive belt, I feel like it shouldn't be this loud. I've also noticed a little tick noise right under the valve covers but it comes and goes. I have gone to two different dealers about the knock, and one dealer says that it's normal, and the other tells me to keep a eye on it. What could this be?

A: It is possible that the recirculation door ...

It is possible that the recirculation door on your vehicle defaults to a particular setting when the vehicle is in park, and the opposite setting when in gear. This could be due to the fact that more outside air is available to the climate control system when the vehicle is moving.

If the actuator that controls your recirculation door is not working properly, oftentimes you will hear this hammering type of sound. I would recommend taking your vehicle back and asking them to check the actuators on your air distribution system. It is very likely that the noise you are hearing is actually coming from under your dash.

Almost all engines will have a vibration that can be felt by touching the valve cover and can often be perceived as a problem when it is actually not. If an engine truly makes a noise, it would be checked with a mechanic’s stethoscope to determine the exact location of the noise; a mobile mechanic can come to your home or business to inspect an engine noise for you.

Considering that you are using the exact oil that Ford recommends for this vehicle, I do not think that your noise is engine-related.

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: What is the PGM-FI system?

Emissions controls have become much more stringent in the US, and your Accord includes several different systems designed to control and manage these emissions. The PGM-FI system is one such. It actually combines three other systems – your fuel control,...

Q: Connector rod vs compression ratio

The short answer would be yes, the connecting rod does have a direct affect on the compression ratio. For example, if you were to use a shorter connecting rod in a given engine when doing a rebuild, a piston manufacturer...

Q: driving the car lost ALL electric and eng just shut off. RPM right to zero.

Hi there. It sounds like you definitely have a short somewhere in the electrical circuit. Is there a burnt smell from the engine compartment? This could be a sign of a short circuit that has melted a wire/harness or component....

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.