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What Does “Engine Threw a Rod” Mean?

What Does “Engine Threw a Rod” Mean?

If a friend tells you that their “engine threw a rod,” you can rest assured their vehicle is in bad shape. “Throwing a rod” is a critical engine issue that usually leads to the end of that engine. 

There are some instances where it can be fixed, but it’s not something that happens very often. Typically, you’ll just have to replace your engine. T

ake a minute now to dive into a deeper explanation of the saying, “engine threw a rod,” and go forth enlightened.  

What Does “Engine Threw a Rod” Mean?

To understand the saying, you have to understand a little about how an engine works. Inside of an engine, there are pistons. Pistons are attached to rods that connect the pistons to the drive shaft. 

The drive shaft provides the “go” power to the vehicle. When gasoline inside the engine combusts, the energy from the combustion forces the pistons to move up and down to push the rods and turn the driveshaft. When an engine “throws a rod,” the rod attached to the piston breaks. 

Pro Tip: Sick of that pesky little check engine light flashing? This is How to Easily Reset Your Check Engine Light.

What Would Cause an Engine to Throw a Rod?

There are a few reasons why an engine might get to the point of throwing a connector rod: low oil pressure, too much engine revving, valve failure, or some loose nuts and bolts. Proper engine maintenance is your best defense against these issues.  

Always make sure you have the right amount of oil in your engine before driving. If you run it dry, you’ll have some pretty bad mechanical headaches in your future. 

Likewise, running your engine too rough can also cause you to throw a rod. Hot rodding isn’t quite as awesome on your car as it might seem to your friends.  

Father and son repairing car engine
If you hear the phrase “your engine threw a rod,” your vehicle’s engine is in bad shape.

Can You Fix an Engine With a Thrown Rod? 

Fixing an engine with a thrown rod is a case-by-case issue. Most times, the rod breaking apart damages the inside of the engine so badly that it simply can’t be mended. The connector rod arms may even punch a hole in your block when it separates.  

The answer of whether or not it can be repaired after throwing a rod heavily depends on how the rod broke. Sometimes it’s feasible to take it apart and refurbish the damaged bits, but it’s always a very costly fix.  

Pro Tip: Before you start cruising, find out Should You Warm Up Your Engine Before Driving?

How Do I Know if My Engine Threw a Rod?

Just like every mechanical mishap, there are a few different ways to tell if you have a connecting rod that has gone awry. One of the biggest hint factors for a bad connecting rod is a knock in your engine. If your engine is knocking, something is loose inside your block. If something is loose enough to knock around inside your engine, you’re looking at trouble ahead. 

A low oil pressure light on your dash is another hint of trouble with your engine. If you can’t get the engine oil pressure to stay in the normal range, there’s a problem. 

A visual inspection could also give you a clear answer on whether or not your engine has thrown a rod. If the rod pierces the engine’s shell, you’ll see it sticking out like a compound fracture.  

Two mechanics repairing vehicle engine.
Fixing an engine rod can run a hefty price tag.

How Much Does It Cost to Fix an Engine Rod?

Depending on the type of engine being fixed, rod repair could cost you anywhere from $2,000 to $4,000 to complete. Mechanics have to pull the engine and take it apart. They’d also have to replace any burnt-up seals, gaskets, connecting rod bearings, and cylinder head bolts, and flush the engine and cooler lines. It’s a big job that comes with a hefty price tag. 

Sometimes it’s just better to get a new engine, especially if the vehicle is an older model. Refurbishing an engine after it has “thrown a rod” will take some time to complete. Don’t expect your vehicle to be up and running in just a few hours.  

What Happens If Your Engine Blows While Driving? 

Throwing a connector rod is a very serious mechanical issue for your vehicle. If your engine throws a rod while driving down the road, you’ll definitely know there’s a problem right away. Driving at 6000 RPMs to 8000 RPMs when the rod breaks? It’ll likely just blow your engine apart. 

If you’re driving slow when it happens, you’ll likely hear a lot of loud knocking under the hood. It’s important that you shut the engine off as soon as possible if you think you have thrown a connector rod.  

Take Care of Your Engine

Voila! Now you understand the basics of what the term “thrown a rod” means. Overall, you should always take good care of your engine to avoid putting yourself in a bad spot.

Make sure your oil is always fresh and full. Don’t rev your engine up into the higher RPMs all the time, and keep an ear out for any weird sounds. 

Has your engine ever “thrown a rod”? Drop a comment below!

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Bruce Steger

Wednesday 30th of March 2022

As a Auto/Truck mechanic for 32 years, I have seen very few engines that can be repaired with a broken rod. In most cases the end of the rod still connected to the crankshaft is flailing around making holes in the block/oil pan. As Jeff below mentioned, a good low Mileage used engine or a remanufactured engine is the best route. It will also result in at least 8 days to replace an engine if they find one quickly. It was so much easier back with carburetor/distributor gas engines/ older Diesel engines with no electronic sensors/controls. Back then I could replace an engine in a little over a day.

Mike K

Wednesday 30th of March 2022

Your cost estimate is way too low. No I've never had a engine that threw a rod, but have repaired ones that had. Lack of oil or oil that needed changing long ago is the most often cause. Engine oil changes are cheap compared to overhauls.

JEFF ALSOP

Wednesday 30th of March 2022

Good Info Viber's! As a retired Auto Tec, I hate to say it, but Labor costs are so high and machine shop / new parts prices as well you are most the time better off to just go get a low mile used motor and plunk it in! I'm talking about serious issues that require tearing down the engine of course! Even a Jasper or other good reman engine is an option.

michael vasko

Wednesday 30th of March 2022

My son did with his first car, lack of maintenance, letting friends use his car... by the time he said anything to me it was to late. The motor was still running but you could hear the knock from a 1/4 mile away. And it only ran for a few minutes more. If he would have kept track of his oil level he would not have had the problem

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