Darn Plastic Raidator

Found a leak



How long will this last?


Just need to wait another 10k mi b4 I do the cooling overhaul.

That crack looks pretty bad. You will never last 10K. Do the overhaul now or prepare to part your car out.

I wouldn't drive it. Next step is complete failure of the connection and all your coolant escaping, then big risk of cooking your engine.

Get a radiator ordered and installed, not worth the risk for the $150 cost of a radiator.

How long will it last?

Up until yesterday.

Do the whole 9 yards, not only the radiator. Check this and other forums about this.

Sorry all. The pic is not that great in quality (dam phone). Its not a hole or crack but more like a micro pin hole. I didn't lose much water at all since it only sprayed a fine mist and only when hot. Cleaned the thing up and patched with LocWeld. We'll see how long it last. Keeping a daily eye on it. I figure ~15psi over an area less than the diameter of a hair should hold back with a patch area >300X its size. If it is a start of a fracture, then hopefully the patch will hold off complete failure for a little while longer.

I have half the parts for overhaul (WP, Pulleys, pump, tank.....). Guess I better tell the shop to order the radiator and the other hoses.

That's a simple job to get your feet wet to DIY. And yes for sure get a radiator as well. 3-5hr for total overhaul for a first timer...

Originally Posted by AnotherGeezer

Up until yesterday.

There goes my coffee!

To the OP, to see why they told you to replace everything, look here:
- Pictorial look at typical E39 cooling system failure modes (1)

Then look here to figure out what to replace:
- Complete cooling system overhaul recommended parts list (1)

Otherwise, if you keep going with that leak, look here:
- The tales of the most recent 50 people who ruined their E39 because of the cooling system overheating (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50)

Originally Posted by SiGmA_X

3-5hr for total overhaul for a first timer...

Hmmmmmm.... it took me about 3 days (elapsed time).

But, I took a thousand pictures, and, well, I broke a few things ...
- How not to remove the nipple from the E39 radiator (broken radiator nipple)
- How not to put your E39 fan clutch back on (crooked fan clutch nut)
- How not to bleed your E39 cooling system (1) (broken bleeder screw)
- How not to replace your E39 thermostat (thermostat loom misplaced)
- How not to remove your E39 expansion tank (broken expansion tank nipple & cn90 repair)
- etc.

Holy crap. 3 days. Jesus.

To the OP, there is no need to rack your brain on reading other peoples' cooling system problems. Please save yourself the headache of any highly probable further cooling system damage and have the system overhauled. All the reading in the world will not benefit your car. Just take the immediate action and get it done. Goodluck and enjoy your car.

Originally Posted by SiGmA_X

Holy crap. 3 days. Jesus.

I'm slow. But methodical!

By way of example, here are the removal instructions for just the shroud!

Originally Posted by bluebee

Lest I forget, here are hastily written instructions for removal of the fan shroud in the 2002 BMW 525i.

I tried to follow the Beisan DIY as much as possible; but I think I snapped MUCH better pictures of some of the steps (e.g., proper removal of the rivets and locations of hoses, etc.) than they did; but you should be able to follow their procedures as well as mine.

Pictures to follow later (I'll append to this post).

REMOVE SHROUD: http://www.beisansystems.com/procedu..._procedure.htm
- Raise the E39 with a jack and put on jack stands (or ramps)
- Remove the under-engine shroud pan (nine #2 Phillips one-twist bolts)
- Draw the hose sequence or snap photos of the underside shroud hose routing.
- Protect your eyes from falling dust with goggles (I didn't and wished I did).
- Locate the auxiliary pump at the bottom driver-side corner of the shroud.
- Disconnect the press-pull auxiliary coolant pump electrical connector
- Slide the auxiliary pump toward the center of the radiator out of the
fan shroud sleeve by lining up the hose in the clamp and tugging gently
- Disconnect both coolant hoses from the fan shroud bottom
- They are held on with two dual-hose clips five single-hose clips, four
of which are on the bottom of the radiator, and one is on the driver's
side about half way up the shroud on the engine side.
- From above, follow the wire out of the auxiliary water pump to the
AUC (stink) sensor on the driver's side in front of the alternator
just under the upper radiator hose elbow.
- Press the plastic clip on the stink sensor connector and pull up to
remove the AUC sensor from the fan shroud.
- Remove the diabolically German 2-inch by 3-inch AUC sensor housing
by wiggling and coercing it, mostly pushing up from the bottom of
the AUC sensor housing and pulling the top of the AUC sensor housing
away from the shroud. Then, once it's a bit loose, switch directions
of force by pushing down on the AUC sensor housing, pulling the bottom
of the AUC sensor housing away from the shroud. You have to just do it.
- With a 3/16th flathead screwdriver pry out (only) the (center)
plastic rivet pin on the driver's side of the shroud near the upper
hose until you can get needle nose pliers on it to pull that center
pin out. Then pry out the base surrounding the center pin.
- Likewise, remove the rivet to the side of the expansion tank.
- Temporarily remove the expansion tank filler cap.
- With two screwdrivers, pry up the escutcheon around the bleeder screw
next to the expansion tank filler cap and remove the escutcheon.
- Replace the expansion tank filler cap.
- Study how the M-shaped rubber seal at the top of the fan shroud sits.
- Pull up on the two-foot long M-shaped seal at the top of the fan shroud.
- Lift the fan shroud up and to the rear of the car; you'll get about 4
inches of room to see the small hose that goes across from the expansion
tank to a nipple on the drivers side.
- BE VERY CAREFUL IN THE NEXT STEP (I broke the nipple right off!)
- Next to the nipple on the driver's side, pry open the original clamp
so that you can remove the hose (I think it's better to dremel it off
because I busted it with very little pressure exerted).
- Remove the fan clutch nut (see separate instructions) with 32mm fan
clutch nut wrench and 48-mm hole spacing fan hub bolt counterhold tool.
- Lift fan shroud and pull fan out toward driver tilting and wiggling
as necessary to get the fan out of the shroud; it will come out aiming
at the driver's steering wheel.
- Beisan says to remove the fan shroud from the engine bay at this point
but I don't see how you can with the expansion tank, it's three hoses,
and the electrical connector on the bottom still connected to the
expansion tank.
- Temporarily remove expansion tank bleed screw with a P3 Phillips
screwdriver.
- Dislodge the expansion tank from the fan shroud by pulling up and
toward the windshield to dislodge the two hoses at the bottom from
the fan shroud.
- Replace the bleed screw with a P3 Phillips screwdriver.
- Pull the drivers side of the fan shroud up and at the same time pull
the bottom hoses of the expansion tank away from the fan shroud.
- Pull the upper expansion tank house through the tunnel in the
fan so that it is not impeding removal of the fan shroud
- Finally, remove the shroud from the engine bay, leaving the expansion
tank still connected to the car.
- Disconnect the frail-looking electrical connector from the bottom of
the expansion tank.
- The Beisans say to place the expansion tank at a high location in the
engine bay but that only made my broken nipple leak more so I put it
at about the same level it was prior.
- As per the Beisans, I tried to keep the expansion tank overflow hose
high to keep coolant from draining out but whenever I raised the expansion
tank, coolant drained out of the broken nipple on the radiator anyway.
Eventually, while I was working on putting the fan on the water
pump, the expansion tank fell to the floor with a full thud, and
I had to jam a branch of wood from my plants into the broken nipple
end on the end of the hose to stave the bleeding mess.
- At this point, the fan is off, the shroud is off, and the expansion
tank is connected but lying on the ground.
- I have access now to the water pump bolt!

How long will it last?on plastic that is already deteriorated...hmm, at least 2days before the day after tomorrow.

Sent from my MB855 using Bimmer App

Originally Posted by Chaser

All the reading in the world will not benefit your car.

This is subjective ... but I'd say yes and no to that statement.

First off, it's true that reading, in and of itself, doesn't overhaul his cooling system.

Yet, the OP seems, based purely on the slight intimation in his initial textual remarks, to be thinking he can 'limp' along with that leak in his cooling system.

That I wasn't the only one who inferred what the OP seems to have implied is inherent in the combined responses by others above.

So, if the OP is inclined to follow advice given to him by people he doesn't know, then he already has all the advice he needs, as nobody who knows the E39 would even think of NOT overhauling that cooling system pronto.

However, if the OP's Myers-Briggs personality is such that he forms his own opinions based on numerous datapoints (which, by the way, is what I do), then all the reading in the world will help him make a better decision!
Note: See Bimmerfest posters' personality profiles!

To that end, we've provided the OP with a bit of select reading; but, if he were to be serious about it, he would read the following (which most of us have read every single post of):
- What to look for when your KTMP (1) or coolant temperature gauge indicates overheating (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) & what to look for in a perfectly normal E39 cooling system (1) & a picture of every failed part in the cooling system (1) & various techniques to properly bleed (1) (2) (3) & refill (1) & drain (1) (2) & flush (1) & what coolant to use (1) & what parts to replace (1) (2) & how to retrofit brass bleeder screws (1) (2) & what special tools to make or buy (1) & how to tell how old your cooling system is (1) (2) & how to test the cooling system auxiliary electrical fan (1) (2) (3) (4) & a DIY for replacing the auxilliary fan (1) (2) (3) & the infamous fuse 75 (1) & the aux fan relay (1) & how to diagnose lack of HVAC/IHKA heater core heat with cooling system (auxiliary pump) at idle (1) & a Behr radiator and Behr/Heat expansion tank autopsy (1) (2) & request for another Behr surge tank autopsy (1) & why new made-in-China Behr/Hella expansion tanks are DOA (1) & E39 Fan shroud removal DIY (Besian) (M54) & some of the better cooling system DIYs (cn90 1997-1998 M54TU) (cn90 V8) (aioros '99-03 M54) (Ågent99 '01 530i) (pelican 3-series) (bluebee M54B25) & tricks to replace the fan clutch nut (1) & lower-hose thermoswitch o-ring (1) & to non-destructively remove the heater hoses (1) or radiator nipple (1) or expansion tank nipple (1) (2) or Oetiker clamp (1) or misplaced thermostat wiring loom (1) or broken bleeder screw (1) & modifying the cooling system pressure cap (1), or using propanol-based zero-pressure fluids like NPG+ (1) (2) (3) (4) (5) or all-aluminum cooling system parts by Zionsville (1) (2) (3) aluminum radiators & what happens if you drive one mile too far with an overheated BMW cooling system (1).

In summary, most of us have read all of those posts, and therefore, we can make a good decision. The OP hasn't yet established that he's convinced of the advice above. That's OK. Luckily I stopped counting the blown engines at number 50 ... so he's safe!

What people are trying to say is that total failure of the cooling system is usually very sudden.

Perhaps you will get lucky and it will break in your driveway but if the thing goes and dumps all of the coolant in a matter of minutes when you're in traffic or on the motorway, you're screwed.

I actually saw something similar happen to a 1990's Z3 the other day, a huge plume of white smoke/vapour from the engine bay when the thing was stuck in traffic. He had no way of getting to the side of the road.

Don't know how lucky you feel but I would very much doubt it would last 10k miles.

Don't forget, the M54 doesn't not respond well to overheating. Do the overhaul before you toast your engine.

"Some things around here don't respond well to bullets"

GROUND the car immediately and start researching "cooing overhaul".
Or you will regret soon.

If you don't have budget for a cooling overhaul, then at the minimum, do the radiator first.
(But doing it piecemeal like this will cost you coolant as every time you open the system, you lose coolant!).
Just skip a few beers and dinners, you will have money for a new rad.

On the issue of brand, there is a debate here between Behr vs Nissens.

I have had good luck with Nissens, now 6 years zero issues.

Well the patch lasted this whole time. Thought it would be 10k by now but only did 8k. There was a new micro leak between the core and tank the other day and since there is time during the Xmas week, decided to do the cooling overhaul and OFH gasket.

Did the job as what the guys in the shop recommended. Went with Nissen but found it was not an exact fit. Fits but there was a little tight around the shroud.

I personally recommend to others reading this thread to address the problem properly, just as everyone else has mentioned here. Do the complete job. Not patch and pray. When there are signs that the cooling is failing, replace all plastic and rubber parts. Even if it was not bad now it will likely fail just after you stress it putting it back together.

http://forums.bimmerforums.com/forum....php?t=1881604

Originally Posted by champaign777

http://forums.bimmerforums.com/forum....php?t=1881604

My next DIY too. I was going to wait until 100k since I am at 94k now but after readingthe warnings and recommendations here on how serious a failure could be I am driving nervous all the time with my eye constantly looking at the temp gauge I'm actually driving my boring camry more until I get this done. I have parts ordered from different sites online.

The only parts I haven't seen before on recommended on any lists are:
Expansion Tank Hose 11531438632 ~30$
Expansion Tank Hose 11531438633 ~23$
Coolant Hose 11531438634 ~26$

These are on your parts list on the link. I guess I will order those too. All I have seen up to now is the upper and lower hoses.