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E60 / E61 (2004 - 2010)
BMW 5-Series E60 Sedan was first seen in the Unites States in the fall of 2003 with a 2004 Model Year designation. The E61 wagon followed shortly there after. The E60/E61 5 series is now available as a 528i, 528xi, 535i, 535xi, 550i and a 535xi sports wagon! -- View the E60 Wiki

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Old 12-11-2012, 04:44 AM
praiford praiford is offline
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Location: Houston, TX
Join Date: Jan 2012
Posts: 25
Mein Auto: 2005 BMW 545i
Coolant Leak

I have being trying to diagnose a coolant leak on my '05 545 for the past month. I don't see any leaks from the water pump or the timing cover area (the dreaded coolant pipe leak) while running. It happens over night or if the car has been parked for 3 or so hours.

I have ordered a new water pump and thermostat and plan to replace them this weekend. The pump is growling now and sounds like the bearings are going.

It "looks" like the leak is in the front area of the engine and sometimes it is pretty substantial from what is on the ground.

Anyone have experience with this or any thoughts/ideas?

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Old 12-11-2012, 05:40 AM
bimmerfan52 bimmerfan52 is offline
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Location: Arizona
Join Date: Feb 2012
Posts: 1,255
Mein Auto: 545i
Three common leak locations on 545i:

- Temperature sensor o-ring on the lower radiator hose
- Coolant expansion tank
- Vent tube (runs under shroud at front of engine bay from top of radiator on drivers side to expansion tank)

Last two will sometimes only leak after engine is shut off (both are involved in "relief valve" role of the expansion tank in the sealed coolant system).

If you have not performed preventive maintenance on your coolant system before, now is the time for a 2005. Belt driven water pumps are cheap for 545i and you'll want to do the thermostat, expansion tank, hoses, belts and fresh coolant. If your vent tube is not leaking now it probably will by the time you get done handling it during disassembly and reassembly. You can either replace the unit (around $40) or replace the plastic tube section with 5/16" copper tube for a permanent fix ($5).

Water pump replacement is not a bad job on the 545i. Biggest PITA is removing the fan and installation of the AC belt (if you don't have the right tool). Handle the plastic parts you are not replacing gently as they become brittle with age.

Consider any other preventive maintenance you may want to do while the car is apart (plugs, air filter, alternator, belt tensioner, etc).

You will have to remove the crankshaft harmonic balancing pulley to get to one of the water pump bolts. Plan on replacing those bolts which are aluminum "stretch" bolts and handle the balancing pulley carefully and set it in a safe place while off the car as they are pretty pricey and can be damaged if dropped on concrete.
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Old 12-11-2012, 07:52 AM
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Jaycal3 Jaycal3 is offline
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Location: Ct
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Posts: 288
Mein Auto: 2004 545i
Check under the expansion tank itself... thats where my 545 leaked from. its hard to see since its underneath. There is a seem under the tank so if you take your hand and run it along that seem your hand will either get wet or it wont.
Deceased - 2004 BMW 545i Black/Auburn
-Sports Suspension, Premium and Cold Weather Package, Logic 7 Professional Audio, Rear Sunblinds, Adaptive Xenon Headlights, Active Steering, staggered setup on 124's, Aux Input

MTEC V3.0 AE's, Black and white roundels, Clear LED Side-markers, New Conti ExtremeContact DWS's, Charcoal Filter Delete, 35% Tint, 20%rear.


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Old 12-11-2012, 09:01 AM
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dolfan13 dolfan13 is offline
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Location: lexington,ky usa
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Posts: 1,147
Mein Auto: 545i
There's a plastic T behind the throttle body that cracked on mine. It routs coolant between the heads and back to the expansion tank.Very easy,4 bolts throttle body removed cracked hose right there.
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Old 12-12-2012, 03:26 AM
praiford praiford is offline
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Location: Houston, TX
Join Date: Jan 2012
Posts: 25
Mein Auto: 2005 BMW 545i
Thanks for the great advice. I bought the small plastic tube that sticks into the block. A good catch on the harmonic balance wheel bolts. I remember seeing that on another thread.
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Old 12-22-2012, 08:38 PM
Patiopat Patiopat is offline
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Location: Vancouver, BC
Join Date: May 2012
Posts: 3
Mein Auto: 545i
I just fixed mine and it was behind the throttle body that had to be removed!
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