Rod bearings are used to fasten spinning shafts, which are parts of the engine and drive train. When one or more of these bearings fail, it can cause the engine not to start at all – that’s how important the bearings are. But what are the rod bearing failure symptoms?
Knocking engine noise, oil check icon illumination, shavings inside the oil, and more are among the signs of a bad rod bearing. Since an engine comprises several rod bearings, it is quite difficult to figure out the faulty/damaged ones if you’re not a mechanic.
However, when you start noticing any of these signs of a bad rod bearing, it is important to act fast – to get the faulty bearing repaired or replaced.
What is Rod Bearing?
Rod bearing is an engine component – a “split-sleeve” type of engine bearing with two separate semicircular halves. The function of rod bearings is to hold (in place) the spinning shafts inside an engine – keeping the rod in a straight position as long as the engine is running.
This type of bearing is different from “Ball Bearings!.” Rod bearings are plain and have two semicircular halves.
Without the rod bearings, the rods inside an engine would dangle and fall around during combustion, and while the engine is running. So, rod bearings are important because they contribute to making the engine run smoothly.
A faulty rod bearing can cause irreparable damage to an engine. Yes, some of the top causes of irreparable engine damage is a bad or broken connecting rod that probably pierced the crankcase of the engine; for a connecting rod to fall out in place, it means the rod’s bearing is no longer in good shape.
“Connecting Rods” are the components that convert and transfer power from the pistons to the crankshaft. The connecting rods are guided in place by rod bearings – the bearings are installed at the “big ends” of each connecting rod where they connect to the crankshaft.
Rod Bearing Failure Symptoms
You’d know you’ve got bad rod bearings to fix when your car start showing any of these unusual symptoms explained below.
1. Silver Shavings in Oil
A bad rod bearing can cause silver shavings to appear inside the oil in your car’s engine. The shavings are the tiny, fine metal particles from the bad (wearing) rod bearing or the connecting rod that is already out in place as a result of a failed rod bearing.
You may notice these silver shavings when you drain the oil to refill a new one, or when you put the dipstick in and bring it out – the shavings would be on the dipstick’s body. Shavings are not supposed to be in the oil because they’d be harmful to the engine when they get inside – flowing with the oil.
2. Knocking Engine Noise
A worn-out, broken or failed rod bearing would cause the connecting rod(s) to hit on the crankshaft; thus, producing an audible “Knocking” noise.
You’d hear the noise each time a connecting rod hits on the crankshaft – and this happens many times – in response to each piston stroke. If this is allowed to linger, the rod would eventually pierce the crankshaft, which may result in irreparable engine damage.
3. Warning Lights are Illuminated
In some cases, a bad rod bearing would cause warning lights to illuminate on the dashboard; this includes the “Check Engine Light (CEL)” and/or “Oil Check” light.
The oil check light may illuminate as a result of low oil pressure caused by the worn-out or failed rod bearing.
What Causes Rod Bearings to Fail?
1. Insufficient Lubrication
Lack of sufficient oil supply to the engine would not only lead to a failed rod bearing but would also affect other metallic parts of the engine. This is the most common cause of failed rod bearings.
2. Improper Installation
If you’ve had the rod bearings changed at some point, and you suddenly start experiencing symptoms of a bad rod bearing – again – then chances are that the bearings weren’t properly installed.
3. Dirt/Debris Inside Oil
If there are debris and dirt inside the lubrication lines, those contaminants would constantly rub on the rod bearing, causing them to wear out faster. Also, the debris or dirt could get trapped inside the rod bearing, which would cause it to malfunction until it fails completely.
Rod Bearing Replacement Cost
The rod bearings are not too expensive, you’d get them for less than $150 depending on the type needed for your car. However, in most cases, replacing the rod bearings would also require replacing a couple of other components; thus, the estimated cost of replacing a failed rod bearing runs in thousands of dollars – $1,500 – $2,000.
The high cost is because you may need to also replace the connecting rod, seals, and some other crucial engine components that may have gone bad as a result of a failed rod bearing.
But if you were able to detect the issue much earlier and get it fixed, you may just need to change only the bearing, which wouldn’t exceed $400 (labor cost included).
How to Fix or Replace Rod Bearings
Although you can do it by yourself, it is advisable to have a professional mechanic do the replacement for you.
This is because if the rod bearings are not installed correctly, they’d fail too soon and you’d be in the market again for a new set of rod bearings. However, if you still wish to carry on with the replacement, here’s the procedure.
Things you need:
- The actual rod bearing for your vehicle
- New engine oil
- Drain pan
If the connecting rods are already pulled out due to the broken bearing, then you have to disassemble them.
To disassemble the rod, remove the clips on the “small ends,” which are connected to a wrist pin that is held onto the pistons. Then, also disconnect the “Large ends” of the rods connected to the crankshaft.
Now, uninstall the rod bearings using a screwdriver (you may need to use the hammer here, too). Carefully and gently remove the rod bearing by hitting the hammer gently on the bearing’s edge(s).
Clean the connecting rods (and the new rod bearings too). Ensure there is no dirt or debris on the surface(s) of any of the components; use a lint-free rag to clean out the surfaces.
Now, install the new bearings; connect the bearing to the connecting rods’ large ends and use the notch to hold them together. If there are other parts of the car you disassembled, re-assemble them and start the car to check out what you did.
Frequently Asked Questions
What Causes Rod Bearing Noise?
Rod bearings can only get noisy when they are worn out or broken. The noise is usually due to the connecting rod(s) hitting the crankshaft in response to the piston strokes from the engine.
How Can You Tell If a Rod Bearing Is Bad?
When you start noticing silver shavings inside the oil in your car’s engine; when the oil check light has refused to turn off; and when you start hearing a knocking noise as your drive, these are common symptoms of a failed/broken/bad rod bearing.
How Much Does It Cost To Replace a Rod Bearing?
Particularly, rod bearings cost less than $150, but in most cases, replacing the bearing would also imply changing a few other components, which pushes the average replacement cost of a bad rod bearing to $1,500 – $2,000 depending on many factors.
How Long Do Rod Bearings Last?
Rod bearings are liable to wear out after several miles. It is advisable to replace the stock/original rod bearings that come with your vehicle after 60,000 – 80,000 miles. Well, you can drive up to 150k miles with stock bearings depending on many factors.
Cost To Replace Rod Bearings Porsche 944?
You can get a new set of rod bearings for Porsche 944 for $60 in most stores. It could be sold for up to $80 in some stores. Labor costs can be anywhere around $50 – $100. So, the average cost of replacing the bad rod bearings in your Porsche 944 is from $120 – $180. This cost applies when it’s only the bearing(s) that needs to be replaced.
In conclusion, what are the common rod bearing failure symptoms? There are just three common symptoms, which are knocking engine noise, shavings in oil, and warning lights getting turned on.
When you notice any of these symptoms, it is important to get the bearings checked as soon as possible before further damages are incurred.