Parts Catalog Accessories Catalog Tech Info Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
BMW E39 Coolant Expansion Tank Removal
 
Bookmark and Share

Pelican Technical Article:

BMW E39 Coolant Expansion Tank Removal

Kerry Jonsson

Time:

2 hours2 hrs

Tab:

$65

Talent:

***

Tools:

Flat head screwdriver, flexible 10mm socket, extension and ratchet,

Applicable Models:

BMW 525i Sedan/Wagon (2001-03)
BMW 528i Sedan/Wagon (1997-00)
BMW 530i Sedan (2001-03)
BMW 540i Sedan/Wagon (1997-03)

Parts Required:

Expansion tank, clamps, bleed screw

Hot Tip:

Crimping pliers to block off hoses will prevent coolant loss.

Performance Gain:

Proper engine temperature

Complementary Modification:

Change the radiator at the same time to stop over heating

The BMW cooling system has used a remote expansion tank design for years now on most of its models. It is usually the highest point of the cooling system which gives it a self-bleeding feature but on new models the tank is mounted to the radiator which means it is no longer the highest point of the cooling system. This means you will need to bleed the system. These expansion tanks can develop cracks and leak and that means they need to be replaced. In this tech article we are going to go over all the steps to remove and replace the cooling system expansion tank.

You do not have to drain and refill the system to perform this repair but it is recommended that you do. BMW recommends that you replace your coolant every 2 to 3 years depending on what BMW coolant you use. See our tech article on refilling and bleeding the cooling system.

We will show you the removal steps on the eight cylinder on engine. The six cylinder steps are virtually identical. Follow the same steps for both engines.

On 8-cylinder models, I like to remove the cooling and shroud along with the expansion tank at times. If I am crunched for time or looking to save steps I will remove just the intake air ducts to the throttle housing. In this tech article I will show you how to remove the expansion tank with the intake air ducts removed, this will help you save time. The first step is to remove the air ducts and mass air flow sensor. See our tech article on mass air flow sensor replacing. Once the sensor is removed, remove the duct to the throttle housing and follow the steps below to remove the resonance chamber.

This photo illustrates underneath the hood on the right side of the radiator.
Figure 1

This photo illustrates underneath the hood on the right side of the radiator. Remove the radiator cap.

Squeeze the two tabs on the plastic bracket around the bleeder screw and pull it up away from the radiator.
Figure 2

Squeeze the two tabs on the plastic bracket around the bleeder screw and pull it up away from the radiator.

Remove the bleeder screw (green arrow) mounted on the expansion tank.
Figure 3

Remove the bleeder screw (green arrow) mounted on the expansion tank.

Move the tank out from under the radiator cover.
Figure 4

Move the tank out from under the radiator cover. Remove the small clamp (green arrow) that holds the small hose to the expansion tank.

If you need more room you can remove the resonance chamber from behind the expansion tank by removing the 10mm mounting fastener (green arrow) and pulling the resonance chamber out of the way.
Figure 5

If you need more room you can remove the resonance chamber from behind the expansion tank by removing the 10mm mounting fastener (green arrow) and pulling the resonance chamber out of the way.

Remove the small hose from the nipple on the expansion tank (yellow arrow).
Figure 6

Remove the small hose from the nipple on the expansion tank (yellow arrow).

Lift the expansion tank up in the direction of the blue arrow.
Figure 7

Lift the expansion tank up in the direction of the blue arrow. Note the two mounting pins that fit into the radiator cover so you can install it later. You will not be able to pull it up very far but just enough so you can see the bottom of the tank.

Unplug the electrical connector for the level sensor by pushing up on the locking tab (green arrow) and pulling the connector in the direction of the blue arrow.
Figure 8

Unplug the electrical connector for the level sensor by pushing up on the locking tab (green arrow) and pulling the connector in the direction of the blue arrow.

If you have hose clamp pliers use them to clamp off the small hose leading to the bottom of the expansion tank.
Figure 9

If you have hose clamp pliers use them to clamp off the small hose leading to the bottom of the expansion tank. If you do not have one when you take off the hose a lot of coolant is going to spill out so have a large drain pan under the engine compartment.

With a flat head screwdriver loosen the clamp that holds on the lower hose of the expansion tank.
Figure 10

With a flat head screwdriver loosen the clamp that holds on the lower hose of the expansion tank.

Separate the lower hose of the expansion tank (green arrow) from the port on the bottom of the expansion tank.
Figure 11

Separate the lower hose of the expansion tank (green arrow) from the port on the bottom of the expansion tank. You can now pull up on the expansion tank and move it out of the way. Installation is the reverse of the removal steps. Join the lower hose and tighten the clamp. Plug in the level sensor in the expansion tank. Mount the expansion tank in the radiator cover and attach the small hose to the nipple at the top of the expansion tank and tighten the clamp. Follow the procedures in our tech article on filling and bleeding your cooling system.

Bookmark and Share
Comments and Suggestions:
Ryan Comments: Found out the answer to my question when I asked my local BMW mechanic about it. The level sensor never is supposed to touch coolant so if your expansion tank is leaking from there, you need to replace both the expansion tank and sensor since the tank broke internally. Hope this helps someone.
February 19, 2016
  Followup from the Pelican Staff: Thanks for the follow up and sharing your experience
- Nick at Pelican Parts
 
Ryan Comments: Is it possible for the level sensor connector to cause a leak and need replacement? I ask because when I pour in coolant into my expansion tank on my 97 BMW 540i, the coolant immediately drains to the ground. When I got underneath the car, it looked like the leak was from one of the two sensors at the bottom of the expansion tank. Thanks for the help!
February 19, 2016
  Followup from the Pelican Staff: There is likely a leak in the tank or sensor. - Nick at Pelican Parts  
David Comments: If you use hose clamp pliers to clamp off the hose and prevent fluid from draining should you still bleed and drain your cooling system?
December 21, 2015
  Followup from the Pelican Staff: You won't have to drain it, but I would still bleed it to be sure there was no air in the system. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Privacy Statement]
 [Contact Us] [About Us] [Shipping] [Map to our Location] [Careers]

Copyright © Pelican Parts Inc.

Page last updated: Fri 12/9/2016 02:05:54 AM