Rear Main Seal Leak

Rear Main Seal Leak Symptoms & Fixes


May 9, 2022

As a beginner, rear main seal leak symptoms are important to identify because it lies between the bell housing and the engine’s oil pan and deteriorates over time.

We’ll show you how to detect and fix this issue in this section of the article, as well as explain alternative options. The following are some of the solutions discussed:

  • For rear main seal and other engine-related oil leaks, we offer the following three parts: — Seal Repair Kits for Engine Oil Leaks (MS-1), Concentrated Rear Main Seal Repair (1040), and Engine Oil Stop Leak Concentrate (1010).
  • VS-1 — for an associated oil consumption problem.

The sooner you address the vehicle indications mentioned in this article, the less money you’ll spend and the less hassle you’ll have with a failing automobile.

What Is A Rear Main Seal And Why Does It Matter?

What Is A Rear Main Seal And Why Does It Matter?

The rear main seal, which lies hidden in the engine compartment, is meant to prevent oil leaks between the block and crankshaft.

Rear seals, as a hard-to-reach component, were intended to endure the life of a car without requiring replacement, unlike numerous other components beneath the hood that motorists are advised to change every few years.

Unfortunately, due to its location at the rear of the engine, oil can easily leak from the back main seal. The consequences of a leaking rear main seal are twofold. A leaking rear main seal will rapidly deplete your oil supply.

The rear main seal is now available in one piece for today’s automobiles. The rope or wick seal was most common among older U.S.-built vehicles, but some manufacturers swapped them out for split seals, which first appeared after the 1950s in Chevy V8 engines.

What Are The Rear Main Seal Leak Symptoms

Rear Main Seal Leak Symptoms

If you suspect a rear main seal leak, it might be difficult to pinpoint since most vehicle owners are unfamiliar with the components in question.

In reality, the rear main seal’s hard-to-reach position demonstrates that this component of the automobile was never intended to be changed throughout vehicle ownership, unlike the battery, air filter, and other components that are easily accessible from beneath the bonnet.

The most common sign of a rear seal leak is when your car begins to leak engine oil more rapidly. Something is wrong with the situation beneath your automobile if it has begun leaving black puddles on your driveway or parking lot.

A warning flag is that you find yourself having to oil your car more frequently than normal, despite repeating the same routes as previously. For example, if the oil pressure light turns red shortly after a new oil change, you likely have a rear main seal leak. As a result of this, indicators of a leak include:

  • Driveways and parking lots are often stained with oil.
  • Oil loss is fast and aggressive.

Oil loss might not be quick enough to detect at the early stage of a leak, especially if the vehicle has been parked in a stretch of concrete where no oil was visible.

While you may notice an oil stain develop over time on your driveway, the leaking might not be quick enough to leave a mark in supermarket parking lots or while the car is parked parallel on city streets. As a result, you may need to perform tests to see whether you’re losing oil.

Is your car leaking oil? To see whether any oil appears on the surface beneath while the engine is idling, 15 minutes is a good time frame.

Because the movement and other vehicle components might hide signs of leaks, the majority of leak indications go unnoticed. Oil may also be splashed on chassis components as you drive to and from work at highway speeds, for example.

When you stop the car, you can see how much oil is consumed during commutes on roads and highways more clearly.

Solutions for Leaks in the Rear Main Seal On A Car’s Engine Bay

rear main seal replacement

The process of replacing a leaking rear seal, regardless of whether a motorist is experienced and knowledgeable in vehicle repair, is often too difficult or time-consuming.

If you’re not afraid of disassembling your engine bit by bit to isolate the problem component, you may be up to the task, but experts in this area will frequently advise that it’s easier said than done.

Rear main seals are notorious for failing, and auto repair businesses have shuddered at the prospect of having to replace them. Rear seal leaks are not good news since they indicate that your car’s rear end needs major maintenance or repairs.

  • It’s all about repairing rather than replacing but make sure you have the right gears for it.
  • The whole worth of this vehicle is greater than most used cars
  • Hard to approach

However, Bar’s Leak’s engine oil leak repair solutions that are award-winning provide an alternative to expensive maintenance and regretful automobile trade-ins. If your car is leaking oil down the road due to a gap in the rear main seal, the following techniques can repair most rear main seal leaks and prevent your vehicle from leaking oil on the highway:

  • MS-1: Formulated to repair oil leaks that are draining your engine of essential oil. Commercial/professional strength. Our most complex oil leak repair solution ever. Available wherever premium car parts are sold.
  • 1040: The most effective method of repairing the concentrated rear main seal is to replace it with a new one. Made to repair damaged seals so that your vehicle may return to the road quickly and securely, with no additional oil loss. Easy to locate in shops or on the internet, as well as award-winning and extremely popular.
  • 1010: Engine Oil Stop Leak Concentrate: To prevent engines from leaking and forming oil puddles in driveways and parking lots, this spring-loaded device is designed to push the rod out of the cylinder. It’s cost-effective, efficient, and readily available.
Puddle of oil under the leak

A very quick side note: if you notice your automobile is losing or burning oil at a faster-than-normal rate, you don’t notice any telltale oil puddles laying on the ground, you park your vehicle and noticed exhaust from your tailpipes billowing every time you switch on the ignition, it’s probably not due to a rear main seal leak. This problem can also be caused by a leaking valve seal, which we frequently hear about from our clients.

The most typical reasons for seal valve leaking include vehicle age and mileage. However, one of the most common causes of a seal leak is long-term storage. When you leave a car in your garage for weeks or months, the seal may dry and harden, resulting in cracks and leaks. Leaks of this sort aren’t as harmful or costly as rear main seal leaks, but they are still an issue that must be addressed.

Stop a valve seal-induced oil leak from getting out of control with the Bar’s Leaks Valve Seal Oil Consumption Repair (VS-1), which is available at Bar’s Leaks. This product is specially designed to seal leaks in the valve seal and prevent future oil burning and consumption.

Leaks in the rear main seal, valve leaks, engines, cooling systems, hydraulics, power steering, and other areas are all addressed by Bar’s Leaks. Click here to see a catalog of all Bar’s Leaks items if you’d like more information on these Bar’s Leaks solutions.

As usual, if you have any queries, please feel free to contact our support staff on Facebook or send us an e-mail. We’re always delighted to assist.


Jeffrey Bryce is an experienced motorcycle rider with years of experience caring for motorcycles. His natural fondness for motorcycles have made him come up with, which is dedicated to answering and teaching you how to care for your bike with the care it requires. LetsGoForARide is the one of his important lifework in reaching out to communities of motorcycle enthusiasts on how to take care of their bike and choosing the correct spare part.