Bad Oil Cooler Line Symptoms

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on February 2nd, 2024

Reading Time: 6 minutes
Summary
  • The oil cooler line is a hose that connects the engine and the oil cooler, enabling lubricating oil to cycle between these two parts. It’s a part of the oil cooling system. Issues with the oil cooling line will disrupt the engine cooling process.
  • Symptoms of a bad oil cooler line include low engine oil levels, engine oil puddling beneath your vehicle, and damaged metal lines.
  • The oil cooler line will need to be replaced at least once before the 100,000-mile mark. A replacement oil cooler line costs between $10 and $560.

What Is the Oil Cooler Line?

The oil cooler line is a hose that connects the engine and the oil cooler. It enables lubricating oil to cycle between these two parts. If something happens to the oil cooler line, it will disrupt the engine cooling process. Unfortunately, the line can develop issues like leaks and crimping that affect oil flow. To protect your vehicle’s engine from serious damage, replace a faulty oil cooler line as soon as your budget and schedule allow.

Note that not every vehicle has an oil cooler, and not every oil cooler has lines or hoses. The oil cooler in this diagram is directly connected to the oil filter and the oil pump outlet. | Image Source: Richard McCuistian.
An oil filter mounted cooler that uses coolant in a heat exchanger will cool the oil as it passes through the filter, but there are no oil lines connected. Some are included in the radiator like the transmission oil cooler, except on the opposite side of the radiator. These have oil lines feeding them. Other oil coolers will be a separate heat exchanger that uses air rather than coolant to cool the oil, and these will typically be fed with lines carrying the oil. | Image Source: Richard McCuistian.

Symptoms of a Bad Oil Cooler Line

Like any other car part, oil cooler lines undergo wear and tear from use until they reach their limit and fail. Fortunately, there are warning signs that you can watch out for to determine if it’s time to replace an old line.

Low Engine Oil Level

You might have a faulty oil cooler line if the engine oil level drops faster or suddenly loses a considerable amount of oil.

When the oil cooler line wears out, its damaged part might leak oil. The leak will deplete the vehicle’s engine oil. It will also reduce the pressure that moves the lubricant through the oil cooling system.

Most vehicles keep track of their engine oil pressure. When the pressure suddenly drops, the oil light on the dashboard will activate to warn the driver.

You can also manually check the engine oil level by pulling out the dipstick and examining the oil mark on it. If the stick shows that the oil level has gone down, check the oil cooler liner and other parts that use engine oil for leaks.

Engine Oil Puddle Beneath Your Vehicle

Is engine oil pooling on the ground beneath your vehicle’s engine? The oil cooler line might have sprung a leak, allowing lubricant to seep out of its damaged section. The larger the leak, the more oil escapes from the faulty part, leading to the puddle spreading faster over a larger area.

There are several ways for an oil cooler line to spring a leak. Its rubber hose segment deteriorates over time when exposed to intense heat, such as the temperatures generated by a running engine. The worn-out metal ends can also come loose from their connection point.

Many other engine parts use engine oil to lubricate their moving parts and keep cool. Check them to confirm if the problem is an oil cooler line leak or something else.

Damaged Metal Lines

Sometimes, the engine will run hotter than it should, as if it wasn’t getting enough engine oil. The problem might lie with the oil cooler line getting bent or crimped out of shape.

Oil cooler lines have metal lines covering both ends of their central rubber hose segment. One end screws into the oil cooler while the other goes into the engine. Both lines fit snugly within their respective inserts to ensure a tight seal and prevent engine oil from leaking.

Although designed for durability, these metal lines can wear out from exposure to engine vibrations and driving over uneven road surfaces. Depending on the situation, they can also get bent out of shape.

Bent and crimped oil cooler lines will restrict the amount of lubricant and the speed at which the oil passes through them. Hot oil will stay in the engine longer while not enough cooled lubricant will return, leading to higher temperatures.

Some vehicles have easily accessible oil cooler lines. You can visually inspect the lines’ metal ends to see if one or both became bent or crimped. Otherwise, you might need to partially disassemble the engine before you can examine the oil cooler line for signs of bending or crimping.

More About the Oil Cooler Line

Usually, supercharged and turbocharged engines will have an oil cooling system to support their radiator-based engine cooling system. These powerful engines produce more heat than their standard counterparts, which requires more capable cooling.

You can usually find the oil cooler line near the engine’s front. That location puts it closer to the oil cooler.

A typical oil cooler line consists of a rubber hose in the middle with metal tubes on both ends. One metal line fits into the engine, while the other goes into the oil cooler. Meanwhile, the flexible hose can bend around corners and expand its width to handle an influx of more engine oil.

What Does the Oil Cooler Line Do?

The oil cooler line plays an integral role in the oil cooling system. Like the engine cooling system, the oil-based system removes excess heat from the engine. The two systems work together to ensure that the engine runs within a safe range of operating temperatures.

Engine oil passes through the oil cooler line to reach the cooling device. As the oil flows through the cooler, it can release the heat absorbed during its passage through the running engine. The now-cooled engine oil can return to the engine.

When Should You Replace the Oil Cooler Line?

The oil cooler line will need to be replaced at least once before the 100,000-mile mark.

The oil cooler line will need to be replaced at least once before the 100,000-mile mark. Refer to your owner’s manual for the recommended time to get a new line. In most cases, hire a professional technician to replace the old oil cooler lines because the arduous task requires special tools.

You can make the oil cooler line last longer by following the manufacturer’s recommended maintenance schedule. Change the engine oil and oil filter regularly. Keeping the oil clean reduces the chances of a clogged line.

How Much Does an Oil Cooler Line Replacement Cost?

You can expect to pay anywhere between $10 and $560 for a new oil cooler line. The replacement part’s price tag can vary according to a number of factors, such as your vehicle’s make and model and the oil cooler line’s manufacturer.

Where to Get a New Oil Cooler Line for Your Vehicle

It’s not a good idea to drive with a damaged oil cooler line, as it could lead to overheating and other temperature-related issues. These problems can make driving a hassle and result in expensive repairs. Luckily, CarParts.com makes finding replacement auto parts and accessories a breeze.

With only a few clicks, you can find the right part for your ride on our website. Find the oil cooler lines that are compatible with your ride by filling out our vehicle selector. Then, find the ones that match your preferred brand, price, and other features using the filters. Check out securely in minutes.

All our parts are on hand and ready to ship from a warehouse near you. Place your order today, and get it in as fast as two business days. And in the unlikely event that you’re unsatisfied with your order, we have a 60-day return policy. Simply file a claim through our returns center, and we’ll issue you a full refund.

Shop for a new oil cooler line and repair your ride in no time.

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

Share
Published by
CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician