(BMW E90) Transmission Problems/Repair Costs/Fluid Change

Last Updated on September 25, 2023 by Robert Wilson

BMW e90 transmission oil cooler problems are a common issue with this model of car.

The main problem is that the transmission oil cooler is located in the front of the engine, and when it fails, it can cause the engine to overheat.

This can lead to serious engine damage, and in some cases, it can even cause the car to catch fire.

The transmission is a complex system, and only a trained professional will be able to diagnose and fix the problem correctly. Don’t let transmission oil cooler problems ruin your driving experience.

BMW Mixing Oil With Coolant | e90 e60 e46 e70 e87

How Do I Know If My Transmission Cooler is Bad?

If your transmission cooler is bad, you’ll likely notice some symptoms that something isn’t quite right. Your transmission may run hotter than normal, and you may see leaks coming from the cooler line.

In some cases, the fluid in your transmission may start to break down and turn brown or black.

What Causes a Transmission Cooler to Leak?

A transmission cooler is designed to keep your transmission fluid at a consistent temperature, but if it develops a leak, it can cause your transmission to overheat.

There are several reasons why a transmission cooler might start leaking. One of the most common causes of leaks is simply age and wear and tear.

Over time, the seals in your cooler can deteriorate, allowing fluids to escape. Another common cause of leaks is damage from debris or rocks hitting the cooler while you’re driving. This can create small holes or cracks that allow fluid to seep out.

How Serious is a Transmission Cooler Line Leak?

A transmission cooler line leak is a very serious issue that needs to be fixed immediately.

If left unchecked, it can cause extensive damage to your transmission and potentially lead to a complete failure. The main problem with a transmission cooler line leak is that it can quickly lead to overheating.

This is because the fluid inside the lines helps keep the transmission cool, and if it starts leaking out, then there’s nothing stopping the heat from damaging the transmission.

In addition, transmission fluid is extremely corrosive, so even a small leak can cause extensive damage over time. So, if you have a transmission cooler line leak, don’t delay in getting it fixed.

Bmw E90 Transmission Oil Cooler Problems

BMW E90 Transmission Cooler Replacement

If your BMW has an automatic transmission, it likely has a transmission cooler. The purpose of the transmission cooler is to keep the fluid in the transmission from overheating.

Overheating can cause damage to the transmission and reduce its lifespan. If you notice that your BMW’s transmission fluid is low or if it looks dirty, it’s probably time to replace the transmission cooler.

The good news is that replacing the transmission cooler on a BMW E90 is a relatively easy task that most people can do themselves.

The only tools you’ll need are a few basic hand tools and a new transmission cooler (available at most auto parts stores).

The first step is to locate the old transmission cooler. It will be located near the front of the engine, just behind the radiator.

Once you’ve found it, disconnect the lines running to and from it. These lines will be attached with small hose clamps which can be loosened with a screwdriver.

With the lines disconnected, you can now remove the old transmission cooler by unscrewing its mounting bolts with a wrench.

Installing the new Transmission Cooler is simply a matter of reversing these steps. First, screw the new cooler into place using the same mounting bolts as before.

Then reattach all of the hoses, making sure they’re tight enough so there are no leaks but not too tight so as to damage them.

Finally, refill your BMW’s Transmission Fluid according to its owners manual (usually this means adding fluid until it reaches the “full” mark on dipstick). That’s all there is too it!


If you own a BMW E90 or are thinking of buying one, you should be aware of the potential transmission oil cooler problems that can occur.

The transmission oil cooler is responsible for cooling the transmission fluid, and if it fails, the fluid can overheat and cause damage to the transmission.

There are a few signs to watch out for that may indicate a problem with the transmission oil cooler, such as leaking fluid or an overheated engine.

If you notice any of these symptoms, it’s important to take your car to a mechanic right away so they can diagnose and fix your BMW E90 problem before it causes any further damage.

Most Common BMW E90 Transmission Failures

  1. Lack of Response
  2. Leaking Fluid
  3. Low Fluid
  4. Burning Smell
  5. Grinding or Shaking
  6. Gears Slipping

(Bmw E90) Transmission Fluid Change (Video)

(Bmw E90) Transmission OIL Change (Video)


  • Robert Wilson

    Introducing Robert Wilson, your go-to source for automotive technical solutions. With 5 years of industry experience and a mechanical engineering background, Robert's expertise was honed at the heart of Ford Motors in Michigan back in 2010. Join him on this blog as he shares his knowledge and practical fixes to keep your vehicles running at their best.

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