Skip the auto shop - Our mechanics make house calls

Q: Knocking from engine.

asked by on

My jeep's engine is knocking.

Unfortunately without more information it will be difficult to narrow down why you are experiencing a knocking sound in your vehicle. In my experience Envoys have had many different reasons that could duplicate an engine knock. The most common is oil starvation. If engine oil is unable to travel through the oil passages to lubricate (this may be due to lack of oil or oil pump failure), metal to metal contact will occur on moving parts. At any time you hear an engine knock coming from your car, turn the vehicle off immediately and check the engine oil. Engine oil is probably the most common reason for the engine knock, especially in higher mileage engines.

Older engines with higher mileage tend to burn and/or leak oil between oil changes. When this happens the crankshaft bearings are usually the first to make noise. When you reach this point, it may be time to rebuild the engine. Rebuilding an engine would be a worst case scenario. If you have sufficient oil on the dipstick and the condition of the oil is good (not black, or contaminated with debris) the problem may lie in the oil pump or elsewhere.

Other possibilities include having bad or noisy bearings on one of the pulleys that drive the accessories. These include the alternator and the A/C compressor. To verify exactly why you are hearing a knocking noise in your GMC, it is best to enlist the assistance of a certified mechanic to inspect and properly diagnose your vehicle so you can get back on the road safely.

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: Engine control modules replaced on a newer car

Hi there. These modules are common failures on the Jaguar XF. I am sure that this does not make you feel any better about it, but from my experience, once the modules are replaced you usually do not have any...

Q: After replacing water pump, thermostat

Overheating has many causes. If you just added coolant after replacing the water pump and thermostat, but did not use the purge points to expel trapped air, that in itself could be the cause. Trapped air in cooling systems causes...

Q: i need the location of the shift solenoid

Hello. The shift solenoid is located in the valve body assembly which is within the transmission. Typically, these solenoids can be replaced without removing the transmission but the job requires care and attention to detail. Of course, if you are...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...