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What You Need To Know About BMW Swirl Flaps and How To Solve The Problem With Them

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  • What You Need To Know About BMW Swirl Flaps and How To Solve The Problem With Them
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28.05.2024

Swirl flaps are a BMW system that has been introduced to help burn the fuel mixture in the cylinder better due to the fact that diesel engines do not have throttle valves and it is not possible to adjust the air-fuel ratio. A diesel engine without vortex valves operates between a poor and a rich fuel mixture, because the only way to regulate it is through fuel injection.

Design of the first generation swirl flaps that are made of made of metal.

Unfortunately, swirl flaps are responsible for countless damaged engines and costly repairs due to design errors or metal fatigue. Once damaged, the cylinder sucks them in and causes great damage.

This is how damaged valves damage the cylinder.

Typical swirl flaps  suction damage.

The vortex valves are positioned in the inlet and are controlled by vacuum (DDE 4.0) or electrically (DDE5.0 / DDE6.4) by the engine ECU.

Effects of malfunctioning valves:

  • Swirl valves are  stuck in open position: Deterioration of exhaust gas performance at lower speeds.
  • Swirl valves are stuck in closed position: Approximate power loss of 10% at high engine speeds.

How swirl flaps work:

Performance characteristics:

The vortex valves are in the closed position, at low engine speeds and small amounts of fuel injected (controlled by the ECU card).

They open under the following conditions:

  1. coolant temperature <14 ° C OR * fuel quantity> 24 mg OR
  2. engine speed 2250 rpm OR
  3. inlet air temperature <-5 ° C

BMW and Pierburg have decided to produce diesel engines with metal vortex valves. The speed at which the pistons in the diesel engine operate is at least 60 rpm, so a sucked vortex valve will break and cause a number of damages inside the engine.

In most cases, one or more pistons are severely damaged, as a bonus you get valves, in some cases a head or turbocharger. And this combination with a BMW engine is like a cumulative jackpot  🙂

In 2004, BMW began work on the problem and improved the design, however, a number of owners reported ongoing problems in this area.

The solution to this problem is by removing the vortex valves and plugging, which does not affect the performance of the engine and at the same time, you can safely pass the exhaust test.

Engines:

M47 (136hp VP44 fuel pump) has no valves.

M47N common rail engine (including M47N / M47TU / M47TUD20) (150hp. Face lift model from 2001 -) has valves.

M57 engines (M57D) (525d & 187hp. 330d) cars with manual transmission do not have valves, but those with automatic have.

M57N engines (M57TUD) (525d & 330d 204hp) have vortex valves.

Ruined swirl flaps:

The plugs that replace the vortex valves are easy to find on the internet, but you can also find them here on our website.

Typical plugs:
 

Disassembly of vortex valves:

The vortex valves can be safely dismantled and in most cases if they are  removed properly no loss of power is felt.

Final list of models for which vortex valves are installed:

Engine: M47N/M47TU/M47TUD20

Applications:

* 110 kW (148 hp) and 330 N·m (243 lb·ft)

o E46 320d 2001-2005

o E83 X3 2.0d (up to end of 2006)

Engine: M47TU2D20

The engine was updated again in 2004 as the M47TU2D20. Still at 1995 cc, it produced more power across the range.

Applications:

* 120 kW (161 hp) and 340 N·m (251 lb·ft)

E60/E61 520d

E87 120d

E90/E91 320d

E83 X3 2.0d (end of 2006 onwards)

Engine: M57/M57D25

M57D25 was introduced in 2000.

Applications:

* 166 PS (122 kW; 164 hp) at 4000 rpm, 350 N·m (260 lb·ft) at 2000-2500 rpm with a 4750 rpm redline, models:

2000-2003 E39 525d *Vehicles With Automatic Transmission ONLY*

Engine: M57N/M57TU/M57TUD25

M57TUD25 was introduced in 2004.

Applications:

* 177 PS (130 kW; 175 hp) at 4000 rpm, 400 N·m (300 lb·ft) at 2000-2750 rpm models:

E60/E61 525d

Engine: M57/M57D30

M57D30, also called M57D29, was introduced in 1998.

Applications:

* 184 PS (135 kW; 181 hp)@4000, 390 N·m (290 lb·ft)@1750-3200 models:

E39 530d *Vehicles With Automatic Transmission ONLY*

E46 330d/330xd *Vehicles With Automatic Transmission ONLY*

* 184 PS (135 kW; 181 hp)@4000, 410 N·m (300 lb·ft)@2000-3000 models:

E38 730d *Vehicles With Automatic Transmission ONLY*

E53 X5 3.0d

* 193 PS (142 kW; 190 hp)@4000, 410 N·m (300 lb·ft)@1750-3000 models:

E38 730d

E39 530d

Engine: M57N/M57TU/M57TUD30

M57TUD30 was introduced in 2002. It originally produced 160 kW (215 hp) at 4000 rpm and 500 N·m (370 lb·ft) at 2000-2750 rpm, but was tweaked for 150 kW (201 hp) at 4000 rpm and 410 N·m (300 lb·ft) at 1500-3250 rpm for 2003 and again for 200 kW (268 hp) at 4000 rpm and 560 N·m (410 lb·ft) at 2000-2250 rpm in 2004.

Applications:

* 204 PS (150 kW; 201 hp)@4000, 410 N·m (300 lb·ft)@1500-3250 models:

E46 330d/330Cd/330xd

E83 X3 3.0d

* 218 PS (160 kW; 215 hp)@4000, 500 N·m (370 lb·ft)@2000-2750 models:

E53 X5 3.0d

E60/E61 530d/530xd

E65 730d

* 272 PS (200 kW; 268 hp)@4000, 560 N·m (410 lb·ft)@2000-2250

E60/E61 535d

* 245 PS (180 kW; 242 hp)@4000, 500 N·m (370 lb·ft)@2000-2250

* 286 PS (210 kW; 282 hp)@4000, 580 N·m (430 lb·ft)@2000-2250

Engine: M57TU2D30

M57TU2D30 was introduced in 2007, making its debut in the facelifted E60 and E61.

* M57TU2D30-UL: 197 PS (145 kW; 194 hp)

* M57TU2D30-OL: 235 PS (173 kW; 232 hp)@4000, 500 N·m (370 lb·ft)@2000-2750

* M57TU2D30-TOP: 286 PS (210 kW; 282 hp), 580 N·m (430 lb·ft)

Applications:

* 197 PS (145 kW; 194 hp), 400 N·m (300 lb·ft) models:

E90/E91/E92 325d

E60/E61 525d/525xd

* 231 PS (170 kW; 228 hp)@4000, 500 N·m (370 lb·ft)@2000-2750 models:

E65 730d

E90/E91 325d

E90/E91 330d/330xd

* 235 PS (173 kW; 232 hp) models:

E60/E61, BMW E70, BMW E71

* 286 PS (210 kW; 282 hp), 580 N·m (430 lb·ft) models:

E60/E61 535d

E70 X5 3.0sd

E71 X6 xDrive35d

E83 X3 3.0sd

E90/E91 335d

The above models are listed for information only if you want to to make sure your engine has valves installed, please contact a competent person.

Please note that the information described above is for informational purposes only and does not claim to be reliable. Mr-key.com is not responsible for any repair work you undertake that is related to the topic described in this article.

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A complete key failure doesn’t just affect the remote functions—it can also affect the chip, the buttons, or even the mechanical components. For instance, if your car uses a push-to-start system and it no longer recognizes your key after a battery replacement, the issue may lie with the transponder chip . This chip is essential for starting the engine, and if it’s been damaged by a drop or water exposure, the car may not respond at all. Keys that have been exposed to moisture , such as rain or accidental washing, are also at high risk. Even small amounts of water can short out the internal electronics or cause corrosion on the contacts, rendering the key useless. Similarly, keys that have been dropped or stepped on can suffer internal damage even if the outer shell looks fine. Another common reason for total failure is button wear . Over time, the rubber buttons on a key can wear down or detach completely, making it difficult to send a signal to the car—even if the electronics are still working underneath. Shell Damage vs. Internal Failure It's important to distinguish between cosmetic damage and a true functional failure. A key with a cracked or broken shell may still work perfectly well, but using it daily becomes inconvenient—or risky, as it can fall apart further over time. In these cases, replacing only the key shell is often the most cost-effective solution. Shell replacement kits are available for most makes and models, including popular FIAT and Hyundai keys. They allow users to transfer the internal electronics and battery into a new casing, restoring the look and feel of the original key without needing reprogramming or electronic parts. However, if the circuit board inside the key is broken , or the transponder chip is no longer recognized by the vehicle , a complete key replacement will be necessary. This often requires purchasing a new key and having it programmed to your vehicle , either through a locksmith or via dealership-level tools. Identifying the Right Replacement Solution The path forward depends entirely on the root cause of the issue. Here’s how to decide: If your key works intermittently and shows no physical damage, start with a battery replacement . If the buttons are worn or the casing is cracked , but the electronics are fine, consider a shell replacement . If the key doesn’t respond at all , even with a new battery, and has no LED or signal , a full replacement is likely needed. If the mechanical blade is damaged , but the remote still functions, you can often just replace the key blade . Replacing just the parts you need can save time and money. Reliable sellers, like mr-key.com , offer a wide range of high-quality key shells, batteries, blades, and even full replacement keys—including options for programming and compatibility details. When your car key stops working, it’s natural to panic. But in most cases, the fix is far simpler than expected. A weak or dead battery accounts for the majority of key-related issues, and replacing it can restore full function within minutes. However, when the damage goes beyond the battery, identifying whether it’s the shell, chip, or internal electronics at fault will determine whether a full replacement is necessary. Being able to recognize the difference between a temporary battery issue and a deeper hardware failure empowers car owners to take quick, cost-effective action. With the right tools and parts—and a little guidance—almost anyone can resolve a car key issue without visiting a dealership. For a full range of replacement parts, including key shells, blades, batteries, and complete remote keys, visit mr-key.com and explore quality products that help restore your car key to like-new condition.

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