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Where exactly do we look on the E39 radiator for telltale cracks?

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Discussion starter · #101 ·
Discussion starter · #102 · (Edited)
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Discussion starter · #105 ·
People keep asking where their leaks are, especially those in the hoses nearer the back of the engine than the front, or on the underside.

So, for the record, here are the six related realoem diagrams for the M54 engine (which is what I have) so that newbies can refer to them if they don't know about realoem themselves.

This shows the key cooling-system components that often fail:
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This stuff generally does not fail:
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Discussion starter · #106 ·

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Discussion starter · #107 ·

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Discussion starter · #108 ·

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Discussion starter · #109 ·
For those reading this thread to get an idea why replace the ENTIRE cooling system when only one component seems bad ...

See this thread from today ...
- Noise under the hood

Where the OP says ...
"I knew I should have changed this when I did the radiator a month ago"

 
Discussion starter · #110 ·
This post by cn90 today clued me in to a good reason why you generally do an entire belt-drive system overhaul at the same time you perform the cooling system overhaul.

" I was going through the twisties three blocks from my barber shop and notice my steering was hard. Look down and battery light is on and check temp gauge and it's going up fast. Get to the end of the last curve and shut down and coast to my shop. Top radiator neck breaks and coolant everywhere. One of the tensioners came apart".

The guy had ALREADY done a full cooling system overhaul.

Then ...
1)The pulley seized.
2)The belt broke.
3)The waterpump was not operating due to drive belt being broken.
4)Engine temperature increased,overheat condition was reached and exceeded.
5)Lower radiator hose began to overheat due to lack of circulation,rubber can take more than German plastic due to its physical properties and expansion.
6)Your radiator neck,being the weakest connection begins deterioration from over temperature.
7)Steam rises and precipitates all over your engine compartment.

*Early signs such as noisy fan belt operation should have been evident.
*These coolant mishaps usually happens under extreme conditions influenced by operation and not environmental conditions or design flaw conditions.
*Great pictures for a great way to educate us all,something to ponder and learn from.
*Check for any further damage and double check your waterpump.
*Replace the map cooling t-stat as preventative,for efficiency and longevity not to mention functionality.
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Discussion starter · #111 ·
Discussion starter · #112 ·

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Discussion starter · #113 ·
Those who continue to drive their car with the cooling system leaking should take a look over here where a leaking waterpump eventually took out the #3 cylinder of a 2002 530i.

Here is all we know (assuming the spark plug move from #3 to #6 was innoculous):

  • Bad waterpump on M54 engine was known to the owner
What was not known at the time was:

  • The DISA valve variable intake vane broke off into the intake manifold and the plate shaft apparently sailed through cylinder #3 before disintegrating
  • Spark plug electrodes on cylinder #3 smashed into ceramic (ceramic intact)
  • Hundreds of little pits in the piston head
  • Both exhaust valves bent
  • One intake valve seat damaged
  • Car appears to have been run for a while on 5 cylinders
So, who knows if the water pump problem somehow affected the DISA valve or not (I'll ask the OP to clarify).

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Discussion starter · #114 ·
BTW, here's what the other side of a broken expansion tank nipple looks like:
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One trick to remove it is to use a 9mm socket from the inside (on a string) to push the three prongs in so that you can pull it out intact from the top of the radiator.
 
Discussion starter · #115 ·
Today, I was helping out someone with an expansion tank bleeder screw leak:
- Expansion Tank Bleeder Screw

So I wrote a thread just on the topic of the bleeder screws:
- How not to bleed your cooling system (i.e., how to break the bleed screw in half)

When I found, during the research, this excellent thread showing BOTH bleeder screws leaking (the one on the thermostat housing and the one on top of the expansion tank):
- E39 OVERHEAT... again!

For the edification of others, here are some pictures showing the leakage from the bleed screws (and from the radiator nipple).

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Discussion starter · #116 ·
Today these pictures were posted of an E39 whose plastic bleed screw somehow fractured ...
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... and at the same time, the bleed screw lost its o-ring.
Image

The OP replaced the plastic bleed screw with a $4 brass screw.
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Discussion starter · #117 · (Edited)
For the record, particularly for those who read this thread AFTER their cooling system has caused damage to the BMW E39 engine head, block, or head gasket ... you have a big decision on your hands.

For help in making that decision, see these similar threads:
- 525i BIG problems!
- Major Decision - replace head or buy "new" engine
- E39 528i Engine removal/replacement
- Overheating and water loss
- Replace head gasket or replace engine
- E39 528i Engine removal/replacement

For a DIY, you might try these:
- Journal: M54 Head Gasket Replacement & Other Stuff Too
- M62TU Head gasket/ Timing guides journal
- DIY This! One Person M54 Cam Removal
(I need more DIY links)
These kinds of threads come about once a week lately, as people unfamiliar with BMW drive are not always aware of how dangerous the E39 cooling system can be when not cared for properly.
 
#118 · (Edited)
Bluebee I hereby dub thee "Official E39 Cooling Care & Maintenance Informer". As always, nice work!
 
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Discussion starter · #119 · (Edited)
Mack said:
Bluebee I hereby dub thee "Official E39 Cooling Care & Maintenance Informer". As always, nice work!
Click to expand...
We all pitch in.

For example, bobdmac just posted part 1 of this wonderful video explaining the BMW cooling system failure points:

bobdmac said:
Here's an excellent video discussion of the cooling system components and issues
Click to expand...
  • Here is part one from bobdmac:
  • And, here's part two from bobdmac:
Everyone should watch these videos.
 
Discussion starter · #120 ·
For those of you coming to this thread to see where the cooling system fails, see Rexgo's overhaul today where the white residue was all over his cooling system ... and notice the jelly at the bottom of his expansion tank!
- Rexgo's '97 528 Cooling O'haul

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