Changing oil is a routine part of a car’s regular maintenance. It not only helps prevent the engine from overheating, but it also helps lubricate engine components, slowing down wear and tear.
Unfortunately, changing your engine oil can lead to a problem known as “knocking,” where the engine produces a characteristic sharp metallic “pinging” sound.
You may ask yourself, “Why is my engine knocking after an oil change?” To answer the question, there could be several possible reasons for that including but not limited to the following;
- An insufficient amount of oil was added to the engine.
- The wrong type of oil was used.
- The oil filter collapsed or was re-inserted backward (particularly if it’s a cartridge-type filter).
- Someone added something to mask the knocking problem, which could be stemming from various issues e.g worn-out rod bearings, pistons, wrist pins, and/or engine rods, during the last oil change. So when the oil was changed this time around, it was lost and the knocking started again.
Contents
What Can Cause Engine Knocks After Changing The Oil?
A Low Oil Level
The amount of oil you add to your engine should be according to your manufacturer’s recommendation. If you don’t consider that recommendation, you might end up providing an insufficient amount of oil to your car.
Consequently, this can cause your engine to experience low oil pressure, a common cause of knocking.
Notably, most cars usually require 5-8 quarts of oil, depending on the engine size. Normally, bigger engines require more oil and vice versa. For example, an 8-cylinder engine often needs about 8 quarts of oil.
A 4-cylinder one, on the other hand, requires roughly 5 quarts of oil. Anything below 4 quarts is considered insufficient, regardless of the engine size.
Wrong Oil
Did you know that the oils used in car engines are not standard across the board? Sure, different engines use different oils with varying characteristics.
These include viscosity indexes, oxidation stabilities, and thermal stabilities. Yet, adding the wrong type of oil to your engine can cause this knocking problem. How so?
Well, an oil that is incompatible with your engine will not lubricate the engine effectively. This will result in friction between the engine’s metal parts including the rods, rod bearings, pistons, and wrist pins.
Consequently, these parts will start wearing out, causing the engine to knock. To avoid that, use only the type of oil recommended by your manufacturer.
The Oil Filter Collapsed, or It Was Put In Backwards (If It’s a Cartridge Filter)
Changing engine oil is not just about draining the old oil and pouring in new oil. Instead, it entails removing and giving the oil filter a little maintenance service(unclogging and greasing it) before inserting it back into the engine. After that, you can add the oil to the oil pan through it.
The filter simply filters the oil that you add to the engine. This ensures that only clean oil that is free from impurities goes into the engine.
Now, if the oil filter is inserted back into the engine improperly, it can collapse. This can reduce your oil pressure significantly. The same can be said for a cartridge-type filter inserted backward.
And as you already know, reduced oil pressure is a big culprit for the knocking problem in car engines.
Someone Added Something(Maybe An Additive) In the Last Oil Change to Mask the Problem
In case you didn’t know, the causes of a knocking engine are not only oil-related. Some of them stem from other issues such as worn-out rod bearings, pistons, wrist pins, or engine rods.
Funny enough, a knocking problem that is being caused by the above issues can be masked with aftermarket additives so that your engine sounds just ok.
So you find that when the old oil is drained and replaced with new oil, the additive is lost, and knocking starts again.
Caution: Some sellers will mask knocking with this trick to sell you a car that has defective engine components. As such, it’s always advisable to ask for an oil change first before buying the car, especially if the engine doesn’t appear to be in a good state.
How To Fix This Problem And Costs
If knocking is occurring due to an insufficient amount of oil in the engine, top the oil back up to the recommended level. On average, a quart of engine oil costs between $3.50 and $6.00.
It all depends on the brand, the type of oil, and where you buy the oil. You may also need to pay for labor if you let a mechanic do the job for you.
Professional mechanics nowadays charge for their services hourly and the rates are usually between $45 to $170 per hour.
Typically, a full oil change will take about 30-45 minutes. An oil top-up procedure should therefore take a shorter duration of maybe 10-15 minutes or so.
If the problem is occurring because you put the wrong type of oil in the engine, replace the oil with the correct one. The amount you can expect to pay here depends on your engine’s oil capacity, without forgetting the average price range of engine oil per quart.
Again, you may also need to pay for labor if you let a mechanic do the job for you. Don’t forget that a full oil change will take about 30-45 minutes and that many professionals charge between $45 to $170 per hour for the service.
If your engine is knocking because the oil filter collapsed as a result of improper insertion, or it was put in backward (if it’s a cartridge filter), pulling the filter out of the engine and installing it properly will help fix the problem.
A mechanic that knows what he is doing will complete the task in 15-20 minutes. Considering the average rates of professional mechanics($45 to $170 per hour), you can expect to pay between $13.13 and $77.92, for a proper oil filter installation.
Lastly, if the problem is due to worn-out rod bearings, pistons, wrist pins, or engine rods, you can expect to part with various amounts to fix it.
The amount you’ll pay depends on the particular root cause whether that be damaged rod bearings, pistons, wrist pins, or engine rods.
All in all, you can expect to pay $2500 for rod bearing replacement, piston replacement, or wrist pin replacement, in general. This cost includes parts and labor.
Is Oil The Only Cause Why the Engine Knocks After Its Replacement?
The short answer is no. As implied earlier, other non-oil-related issues can also be responsible for the engine knock problem after an oil change. These include worn-out rod bearings, pistons, wrist pins, and/or engine rods.
Will Adding Oil Stop the Engine Knock Problem?
Sure, if the engine is knocking because of an insufficient level of oil.
Can An Oil Change Fix Engine Knocking?
The short answer is yes, especially if the engine is knocking because of the presence of the wrong type of oil in it.
Conclusion
A few issues can cause the problem of your engine knocking after an oil change, but most of the knocks are caused by adding the wrong oil or adding an insufficient amount in the engine.
