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BMW E39 Cooling System Filling and Bleeding
 
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Pelican Technical Article:

BMW E39 Cooling System Filling and Bleeding

Kerry Jonsson

Time:

1 hour1 hr

Tab:

$45

Talent:

***

Tools:

Large flat head screwdriver

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:

Bleed screws, coolant

Hot Tip:

Work when the system is cool

Performance Gain:

Stop over heating and poor heater output

Complementary Modification:

Replace thermostat

BMW recommends that you replace your engine coolant every 2 to 4 years depending on the year and type of coolant used. If you only drain the coolant from the radiator you are not getting all of the coolant out of the system as there is coolant left in the block. There is a block drain plug that you can open to drain the coolant in the block. If you replace your water pump you will also drain quite a bit of coolant from the block. One of the more difficult tasks after servicing your cooling system is completely filling the system with coolant. Due to complicated castings, extra hoses and preformed coolant tubes air can easily get trapped in the cooling system causing hot spots and, depending where the air gets trapped, reducing coolant flow. To purge the air out of the cooling system BMW has provided a bleed screws which should be used during a bleed procedure. In this tech article we will go over the steps to bleed the cooling system of your straight 6 or V8 engine.

Draining the Coolant:
This photo illustrates underneath the car on the left side.
Figure 1

This photo illustrates underneath the car on the left side. At the base of the radiator remove the 17mm drain plug (green arrow) bolt and drain the coolant into a drain pan.

Most engines will have a 13mm drain plug (green arrow) on the side of the block.
Figure 2

Most engines will have a 13mm drain plug (green arrow) on the side of the block. Remove the drain plug and catch the coolant with a drain pan.

Filling and Bleeding:
This photo illustrates underneath the hood looking at the front of the six cylinder engine at the plastic thermostat housing.
Figure 3

This photo illustrates underneath the hood looking at the front of the six cylinder engine at the plastic thermostat housing. Open the bleed screw on the thermostat housing but you do not have to remove it all the way.

If you have the eight cylinder engine open the bleed screw next to the filler neck
Figure 4

If you have the eight cylinder engine open the bleed screw next to the filler neck on the expansion tank at the right side of the radiator

On the right side of the radiator you will see the cooling system expansion tank.
Figure 5

On the right side of the radiator you will see the cooling system expansion tank. Add coolant to the expansion tank slowly.

Fill the cooling system until fluid comes out of bleed screw on the thermostat housing.
Figure 6

Fill the cooling system until fluid comes out of bleed screw on the thermostat housing. You may want to give it a few minutes and add coolant again and then close the bleed screw on the thermostat housing, do not over-tighten since it is only a plastic screw.

If you have the eight cylinder you need to open the bleed screw on the expansion tank.
Figure 7

If you have the eight cylinder you need to open the bleed screw on the expansion tank. Continue filling the cooling system slowly until coolant starts to flow out of the bleed screw in the expansion tank.

If you have the eight cylinder you only have to add coolant until it starts to come out of the bleed screw on the expansion tank.
Figure 8

If you have the eight cylinder you only have to add coolant until it starts to come out of the bleed screw on the expansion tank. Fill the system slowly if you can. Finally close the bleed screw.

Start the engine and set the heater controls to maximum heat and the fan on high.
Figure 9

Start the engine and set the heater controls to maximum heat and the fan on high. Let the car run until the thermostat opens and the lower radiator hose starts to get hot.

Let the engine cool off and on the six cylinder follow the steps repeating steps 3, 5 and 6.
Figure 10

Let the engine cool off and on the six cylinder follow the steps repeating steps 3, 5 and 6.

If you have the eight cylinder you only have to open the bleed screw on the expansion tank until coolant starts to run out of it.
Figure 11

If you have the eight cylinder you only have to open the bleed screw on the expansion tank until coolant starts to run out of it. Then close the bleed screw. Repeat the process until only coolant flows out of the bleed screws. When youÂÂ're done your temperature gauge should stay at the halfway mark on the temperature gauge.

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Comments and Suggestions:
RobbieFitz Comments: Hi guys, is it possible to do this without using the aircon controls. Mine don't work and I haven't been able to find a solution to that issue.
September 26, 2017
  Followup from the Pelican Staff: Yes, you will have to idle, let cool, top up, and repeat until bled. Do not let engine heat up past halfway during bleeding process. - Nick at Pelican Parts  
NottinHell Comments: Many thanks for your reply
Is there any DIY for compression, leakdown, and coolant system pressure tests?
Also, could the reason be a CCV crankcase Ventilation Valve or its unlikely?
June 27, 2017
  Followup from the Pelican Staff: Not likely a CCV. We don't have the articles you requested, but I found a few good ones here:

Compression test video here: https://vimeo.com/208371361

Leak down: https://vimeo.com/208666749- Nick at Pelican Parts
 
NottinHell Comments: Hi,
I have an E39 523 / 1998
Yesterday while I was going for a long trip, I found the car temperature increased & "check coolant" message!
opened the hood found the radiator cover leaking steam & the car was too hot.
when it cooled down found no water & after refilling it car got hot again, fan is working properly, when it cooled down and refilled water i noticed that water decreases while the car is not running.
Please HELP....!!!
June 25, 2017
  Followup from the Pelican Staff: I would pressure test the cooling system. If the system will not hold pressure and there are no external leaks the head gasket may be faulty. - Nick at Pelican Parts  
harley mech Comments: hi nick harley mech here.....so pressure switches determine when fan comes on during a/c opertion...so these switches would be somewhere within the a/c circuit? any info would be of great help. thanks
June 13, 2017
  Followup from the Pelican Staff: Yes, on the high side line. It may a transducer, you will want to consult a wiring diagram to be sure which type of switch it is. - Nick at Pelican Parts  
harley mech. Comments: hi, electric cooling fan.....is it suppose to come on when a/c is turned on ? and will it come on automaticly when temp. hits 106 ? took plug off temp switch and jumped pins 1&2 and fan comes on with ignition in on position engine off, so does this indicate that temp switch is bad ?
June 11, 2017
  Followup from the Pelican Staff: Yes, it should come on when stationary with A/C on. Temp switch does not control A/C command of fan, pressure switches do.- Nick at Pelican Parts  
Chedley Comments: Bleeding procedures on the V8. But it should on any engine.

1. Drive, or run engine with heater on at max temp.
2. Overheat -the temp indicator will go past 12'oclock mark.
3. Stop immediately preferably on an inclined level so that the front of the car is elevated and turn off the engine. Never run your car engine with temp indicator in the red range beyond the 12'oclock mark.
4. Open bleed screw, and wait for cooling down of the system -in about 15 minutes-
5. Squeeze the top -and bottom- coolant hoses several times to push out air pockets.
6. Refill tank with coolant until the indicator is at max, then close the cap and the bleeding screw.
7. Repeat, Go to Step 1

You should loop 2 or 3 times thru these steps to completely bleed air out of the system.

Note that this procedure will detect any possible leak in your radiator/tank/hoses of your cooling system.
May 6, 2017
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
Farmerapps Comments: Hi, I have a 2001 530i and my mechanic told me to open the bleed screw on the side of the expansion tank as well where as you say this is only for the 8 cylinder car. Who is right please?
December 22, 2016
  Followup from the Pelican Staff: If you have a bleeder on any component, open it when filling. Close once trapped air is finished escaping. - Nick at Pelican Parts  
Jeremy Comments: Hi Nick
I am trying to remove the blue plastic radiator drain plug BMW 530i 2001. It lessens a 1/4 turn and then won't turn further. I'm afraid of using too much force and damaging the plug. The blue plug has a tab for pliers to grab but no bolt or screw head. Any ideas would be appreciated.
October 14, 2016
  Followup from the Pelican Staff: Twist it 25° and pull down, it should finish the 90° motion as it comes out downward. - Nick at Pelican Parts  
Mack Comments: 2 years later still no correction to step 10..!!!
August 20, 2016
  Followup from the Pelican Staff: I resent the note to update the article. Thanks for staying on top of us. - Nick at Pelican Parts  
TroycadA5 Comments: From1 to 10 scale how difficult to replace yourself the expansion tank
For 2003 530i
August 1, 2016
  Followup from the Pelican Staff: See this article:

http://www.pelicanparts.com/BMW/techarticles/BMW-5-Series-E39/60-WATER-Coolant_Expansion_Tank_Removal/60-WATER-Coolant_Expansion_Tank_Removal.htm - Nick at Pelican Parts
 
TroycadA5 Comments: Is a necessary to drain coolant on 530i 2003
Before replacing expansion tank
August 1, 2016
  Followup from the Pelican Staff: You can drain until the tank is empty, then clamp hoses to prevent spilling. - Nick at Pelican Parts  
Big Al of Bondi Comments: Hi, is it possible to reuse the drain plugs on the radiator and engine block? Thanks
February 25, 2016
  Followup from the Pelican Staff: Yes. Replace the seals though. - Nick at Pelican Parts  
Mick Comments: How much coolant is needed ?
January 9, 2016
  Followup from the Pelican Staff: For what vehicle? Most E39 models take 3 gallons. - Nick at Pelican Parts  
Mechatech Comments: I have a 03 525i with 2 bleed scrues is the procedure he same?
November 14, 2015
  Followup from the Pelican Staff: Yes, just open both bleeders at the same time. - Nick at Pelican Parts  
Steve Comments: Thanks for the great tech articles. I have a question about cooling system filling and bleeding. Step 11 states "on six cylinder follow steps 1, 4 and 5" Step 1 involves draining the radiator again, Step 4 pertains to eight cylinder engines, Step 5 makes sense. Repeating steps 3, 5, and 6 would make more sense. Am I correct, or am I missing something?
May 8, 2014
  Followup from the Pelican Staff: Thanks for catching that typo (error). We will adjust the article. You are correct with steps 3, 5 and 6. - Nick at Pelican Parts  

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Page last updated: Sat 10/21/2017 02:06:25 AM