A rupture inside or on a part linked to the engine is the main reason the rear main seal fails. As many car owners know, rear main seal replacement is one of the most expensive, time-consuming, and feared repairs on your car. This kind of news could ruin their day. At a store, it might cost $600 to $900 or even more. Don’t worry; there is an easier way to get there. It’s not a final fix, though. To make a long story short, this piece will talk about the signs of a rear main seal leak, what causes them, and how to fix them.
Are there oil pools under your car, especially when the engine is on? That could be one of the most evident signs of a rear main seal leak. Don’t be shocked if a professional tells you that the oil leaks from the rear main seal. The rear main seal is one of the most critical seals in your car. You wouldn’t expect it to leak unless you’re dropping your engine or transmission since you must take it apart to get to it.
What Does a Rear Main Seal Do?
How does a back main seal work? What is it?
The rear main seal keeps the back end of the crankshaft from leaking. It is located at the back of the engine, between the engine and the transmission. Fixing it costs a lot because the transmission or engine has to be taken apart most of the time.
When a car has front wheels, the engine is usually placed diagonally. This means that the idler pulleys, tensioners, and serpentine belts are on the side opposite the back of the engine. If you’re not a gearhead like me, it’s hard to figure out when the rear main seal leaks oil into the engine. The oil usually leaks from where the transmission ties to the engine and into other places, like the crankcase.
Most of the time, silicone or rubber is used to make the back crankshaft seal. Over time, corrosion from road salt, the crankshaft’s rotational forces, and other external factors cause the seal to wear out. Driving with a rear main seal leak is very dangerous because the engine could break down completely.
Signs of a Rear Main Seal Leak
Because of where this seal is located, it is complex and complicated to find and fix an oil leak. The driver will notice some symptoms if the rear main seal is broken or leaking, just like with any other mechanical part.
Puddles Of Oil
Most of the time, oil pools on the garage floor or road mean that the rear main seal is broken. You can see these oil puddles when the car moves or stops for a long time. But oil can leak from different parts of an engine. Still, you should find out where the oil is coming from before you decide it’s the rear main seal.
Smoke coming from under the car
When the rear main seal leaks, it often drips on the tailpipe, making smoke come out from under the car. No matter what, you should be able to tell the difference between smoke from under the car and from the tailpipe. If you see smoke from the tailpipe, the engine is burning extra oil, not a back crankshaft seal leak.
Building Up of Dirt and Junk
Leaks of oil stick things together. Suppose your rear main seal leaks; dirt and other unwanted stuff from the road will stick to the oily spots. This is an early sign that a part is leaking. If dirt and other things build up between the transmission and the engine, the rear main seal leaks. It would help to have a back-leading sealer to stop the leak.
Quickly Lowering the Oil
If your car suddenly started losing a lot of oil, and there don’t seem to be any leaks or damage to the engine, the problem is probably with your rear main seal. This kind of leak can be caused by several things, such as seals that are worn out.
During regular maintenance, you can see that the oil amount on the dipstick drops to a level you didn’t expect. In cars that lose engine oil quickly, there will be noise while the vehicle moves and the engine oil light will keep blinking. In this case, the best thing to do is check your car oil every morning before you leave for the day.
What Makes the Rear Main Seal Leak?
Many things can make the rear main seal break. Let’s quickly look at the things that can damage or bend the rear crankshaft seal.
Condition of the Engine Oil
If you use the wrong engine oil or don’t have enough oil in the engine, the rear crankshaft seal could leak. There are chemicals added to most engine oils that could damage the parts in the engine. The seals will wear out if you don’t change the oil regularly. The seals and guards in the oil will wear out over time. It will dry out and become stiff, so the inner lip that drives on the crankshaft will no longer be able to seal the crankshaft.
The Main Bearing is Worn Out
If the main bearing in your engine is damaged or worn out, the crankshaft will dangle inside it. This will cause the rear crankshaft seal to stretch and move while the engine is going. This likely means that your engine’s main bearing is worn out. If this is the case, you’ll have to fix your car’s engine and replace many other broken parts with the rear crankshaft seal. It will be a big repair job.
Condition of the Crankshaft
The bumper on the back of the crankshaft seal rides on it. So, the surface of the crankshaft that the inner seal rides on is critical. A leak can happen if the engine is worn or has other flaws. Putting a sleeve kit on the surface will bring it back to life.
Clogged or Broken System of PVC
When there is too much pressure from the crankcase, the inner lip of the rear crankshaft seal will ride on the shaft and drag the seal onto the crankshaft. This will cause the seal to swell, which will cause an oil leak. There is too much air in the crankcase because of what? If the positive crankcase ventilation (PCV) system is clogged or broken, the engine pressure will rise, which could cause the seal to come loose.
Also, if you have a turbocharged or supercharged engine, too much engine blow-by from broken or worn-out piston rings can raise the crankcase pressure, which can damage the seals and cause oil leaks.
Issues With Misalignment
Issues with the transmission’s input shaft or a broken flex plate can stress the rear crankshaft seal, regardless of your transmission. If you have an automatic gearbox, look for damage to the flexplate. Check the input shaft on cars with manual gears.
Coating the Seal
There are polytetrafluoroethylene coatings on some rear engine seals that are meant to be put on dry. The seal will send a layer of PTFE to the crankshaft so that the inner lip has something to sit on. PTFE will last longer than Viton or silicone and close better than those materials. If you put oil on the seal while it’s being installed, it will leak soon after.
How Much Does a New Rear Main Seal Cost?
Most of the time, the back main seal is very cheap. Most of the time, you can get the part for less than $50. In the end, the crankshaft’s rear main seal is just a bit of metal with rubber.
The bad news is that taking it off can be very hard. You will always have to take the car’s engine out of the transmission or the transmission out of the engine.
If your engine is different, you may also need to take out the transmission, the crankshaft, the camshaft, and the valve covers.
Changes Made How Much Rear Main Seal Replacement Cost?
Most of the time, the back main seal costs between $20 and $100. The average cost to replace a rear main seal is still $1,100, which is a shame.
Costs of work are the most important thing here. The exact prices, though, depend on what kind of car you have. Why? Different things go into making engines.
We’ll discuss the prices of rear main seal replacement cost below.
Building an Engine
Depending on the engine, it can take anywhere from a few hours to well over eight hours to take out the transmission and put in a new main seal.
Different makes and models may need other parts to be taken apart, such as the cams, cam seal, engine, transmission, clutch, clutch release, and more.
Of course, you’ll need to take out fewer parts if your gear is automatic. The transmission oil will always need to be changed after that, though.
All of this means that it costs a lot to replace your crankshaft cover. You can expect to work at least 8 hours most of the time.
Sometimes, your transmission is easy to get out. With some Toyota models, taking out the transmission and changing the seal is pretty simple.
Instead, you’ll probably have to work here for three to four hours. Most of the cost comes from the work, no matter what.
Mechanic Pay Rates
Rates for mechanics and garages can be very different. These rates are between $15 and $210 an hour nationwide. $60 an hour is about what it sounds like.
Still, it’s true that the rate per hour changes depending on where you live. It would help if you also considered whether you want to go to a dealer (more expensive) or a neighbourhood shop.
For instance, if you own a rare car, you might not be able to find a mechanic in your area who can fix it.
Along with that, you’ll have to pay parking rates. This is how much you spend each day that your car stays in a mechanic’s shop.
Most of the time, replacing your main seal will take a few days. You’ll have to pay parking fees for at least two days.
This rate is usually included in the price, though. Also, a lot of lockers don’t charge the fee at all.
Type and Make of Car
The parts will cost more or less depending on what kind of car you have. On the other hand, the work cost is likely to make this a minimal amount.
You might have to pay up to $200 for a new ring if you have a speed or sports car. More often than not, rates range from $25 to $60.
Also, auto parts shops, Walmart, and Amazon almost always have alternatives that other companies make. These could be Broken Parts.
If the expert takes your car apart and finds more damage or leaks, it will cost more. While you have the transmission out, changing other parts is sometimes a good idea.
One example is that if you know the clutch is almost worn out, changing it while the transmission is out could save you a lot of money over pulling the transmission out again later.
Of course, that depends on how old and broken down your car is.
How to Replace the Rear Main Seal?
A rear main seal leak can be nasty for your car. You need to fix the hole right away if you’re losing oil there because it could do a lot of damage to your engine. Fixing a seal that has shrunk, is slightly worn down, or has become misshapen because the oil was changed too often doesn’t take much time. If this is the case, the seal doesn’t need to be changed; it just needs to be fixed up.
It’s not news that engine seals break down over time because of heat, acidic oil, and other problems usually caused by not maintaining the engine. In this case, you need the rear main seal to stop the leak and fix the seal so it works for another few thousand miles.
Get a blue devil rear leading sealer to fix the back main seal. This product is made to stop the leak from the rear main seal. This is done by fixing rubber gaskets and seals. It’s also a great way to fix timing cover leaks and is safe for gas and diesel engines. Also, both manufactured and regular oils can be used with it. Remember that this won’t work if the seal is broken, torn, or has a hole. A big hole or chunk in a rubber seal can’t be fixed with anything. If your rear crankshaft seal has a big hole, take these steps to fix it.
Take The Battery Out
Separate the negative battery wire since you need to take the starter off. Take the battery lead off so there isn’t a sudden electrical shock or short circuit.
Remove The Transmission
On some cars, you must take off some crucial parts first, like the exhaust system and axle, to remove the transmission. Get rid of whatever is stopping you from getting rid of the transmission. In order to work on an automatic car, you will need to separate the torque converter from the flex plate. With the correct socket size and ratchet handle, take out the torque converter nuts one at a time. If you lose the first bolt, turn the engine counterclockwise until you find the next one. Then, lose the next bolt, and so on, until all of the nuts are gone.
Take Off the Flywheel
You must take off the clutch and flywheel if you have a car with a manual transmission. If you have an automatic transmission, on the other hand, you will need to take off the flex plate.
Take Off Main Seal Bolts On Back
First, take off the transmission, then the clutch, and finally, the flexplate. Next, take off the back main seal. There may be crankcase bolts that connect the crankcase to the rear crankshaft seal housing. Try to break these bolts loose and remove them. There are 10mm or 12mm bolts hold the rear crankshaft seal cover to the back of the engine block. Remove the seal housing by taking off these bolts. To get the case off, you should use a Flathead screwdriver to pry it off.
Take Out Seal On Rear Crankshaft
You may also find getting the rear main seal off the housing hard. You should slowly pry it off and remove it from the housing.
Look The New Seal
Now, put the old and new seals next to each other and look at how they look. The inner and outer diameters of the new seal should match those of the old one.
Put In The New Rear Main Seal
Clean the seal cavity very well. Wipe off the old seal on the case with a gasket scraper. Put the seal into the frame and hammer it in evenly. Don’t forget to put oil on the cap. Put a thin layer of glue on the surface after placing the seal.
Put Rear Main Seal Housing In Place
Set up the seal box and ensure all the bolts are tight, including the ones on the crankcase. Use the opposite process to return everything you took out earlier.
Conclusion
All of this means that you should always be on the lookout for signs of a rear main seal break and act quickly if you find one. rear main seal replacement might be tricky if you’re not a gearhead. Just because the process is complex doesn’t mean it can’t be done. You can do it independently, but it will take much time and work. To cut down on fixed costs, you should always put safety first.
