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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #1  
Old 01-27-2018, 03:01 PM
santaclaus500 santaclaus500 is offline
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523i -97 losing coolant very quickly

Hello peeps, my car has been losing coolant quite fast recently (nearly full reservoir/30miles), the car runs, starts and drives very well and the temp gauge stays put and has never overheated, I thought it was the reservoir o-ring where it attaches to the radiator. I replaced the expansion tank with new o-rings and when I pump the upper radiator hose I can see continuous dripping 2 inches below the reservoir, I bet the leak gets quite severe when giving the engine some foot while driving. I checked the coolant return hose for cracks/deterioration and it seems to hold it's own.

Can't really get a look underneath, so has anyone got any kind of idea where it could be leaking from? My car has the reservoir on the drivers side and it's the white one as in E36.
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  #2  
Old 01-27-2018, 07:55 PM
edjack edjack is online now
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You need to remove the belly pan and get under the car.
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Old 01-28-2018, 04:18 PM
arthurwood arthurwood is offline
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I feel for you as I had to once track down a leak and I never did find it.
I replaced everything except the hard pipes, and one of those fixed the leak.
But I couldn't find it by looking.

As said above, you have to remove the engine pan and look. I lost mine long ago as I don't see what it does for what it gets in the way of.
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Old 01-30-2018, 04:14 AM
santaclaus500 santaclaus500 is offline
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Yeah, I ordered a new off brand radiator anyway.

What hard pipes are you speaking of? Mine seems to have none near the radiator since it is manual with no ac, only upper and lower coolant hoses and the tank return line.

I guess it might have a pinhole or a crack at the bottom, I'll update here if I find the fault when I have removed the radiator for a better look, since I can't really get underneath it now.
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Old 02-08-2018, 09:58 AM
santaclaus500 santaclaus500 is offline
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Yeah so the off brand core I ordered was all wrong so I went to a local shop and bought a hella/behr radiator, was pretty easy fix, seems to be holding coolant now, atleast for the small distance I drove. I couldn't find a leak on the old one, must have been a crack hidden somewhere.

Smacked the damn fan clutch nut for 3hrs tho without any luck, held against with a long prybar, nothing. Had to take the fan off the clutch, should have done so at first because it was very easy.
Just hoping the smashing didn't damage the water pump bearing.
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Old 02-08-2018, 10:08 AM
arthurwood arthurwood is offline
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Quote:
Originally Posted by santaclaus500 View Post
Yeah, I ordered a new off brand radiator anyway.
It's more often the expansion tank, but the radiator has a problem area in the plastic.

Quote:
Originally Posted by santaclaus500 View Post
What hard pipes are you speaking of? Mine seems to have none near the radiator since it is manual with no ac, only upper and lower coolant hoses and the tank return line.
There are two of them. Under the intake manifold. It's easier to see them in a realoem diagram, but here's a photo of what's under my intake manifold from last week.


Quote:
Originally Posted by santaclaus500 View Post
I guess it might have a pinhole or a crack at the bottom, I'll update here if I find the fault when I have removed the radiator for a better look, since I can't really get underneath it now.
There are something like a dozen soft rubber hoses and hard plastic pipes in the cooling system, any of which can leak. You have to find the source to know what to replace.

Quote:
Originally Posted by santaclaus500 View Post
Yeah so the off brand core I ordered was all wrong so I went to a local shop and bought a hella/behr radiator, was pretty easy fix, seems to be holding coolant now, atleast for the small distance I drove. I couldn't find a leak on the old one, must have been a crack hidden somewhere.
Maybe. Let's hope. Nothing wrong with replacing the radiator though as the plastic will eventually go anyways.

Quote:
Originally Posted by santaclaus500 View Post
Smacked the damn fan clutch nut for 3hrs tho without any luck, held against with a long prybar, nothing. Had to take the fan off the clutch, should have done so at first because it was very easy.
Just hoping the smashing didn't damage the water pump bearing.
They sell a special set of tools for that.
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Old 02-08-2018, 10:08 AM
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mattmar1 mattmar1 is offline
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just an off chance question...you are aware the fan clutch threads are left hand threads correct?
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Old 02-08-2018, 11:51 AM
santaclaus500 santaclaus500 is offline
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Tried swapping the reservoir and seals before and it was still leaking, I'm 150% sure none of the hoses and pipes aren't leaking, it was near where the expansion tank sits.

I couldn't wait weeks to get the special tool off ebay, can't get it locally you see.

Yes I am aware it's a reverse thread nut, I was whacking the 32mm wrench towards the drivers side fender, it just wouldn't budge. I bet someone had tightened it with a huge grin on his face and sweat dropping off his forehead, when the waterpump was last replaced.
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Old 02-08-2018, 12:34 PM
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Normdude Normdude is offline
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I just had to replace my drain plug in the radiator. Itís started as a small leak and I thought it was the radiator leaking until it totally fell out. Also I just did my thermostat and ordered the clutch fan tool from Amazon and I got it the next day with there prime thing they offer


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Old 02-08-2018, 01:51 PM
santaclaus500 santaclaus500 is offline
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Unfortunately amazon works awfully for me, since I live in Finland, it's like 10 times the item price and atleast a week for shipping.

My radiator leaked above the plug, so couldn't have been as simple yours. :/ But thanks for your input anyways.
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Old 02-08-2018, 06:37 PM
arthurwood arthurwood is offline
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Some say bicycle wrenches are thin enough to work but I have never tried them.
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Old 02-08-2018, 08:20 PM
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mattmar1 mattmar1 is offline
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when installing the fan clutch, just a tad of antiseize compound on the threads makes a better next time removal.
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