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How can I tell how old my cooling system is?

24K views 64 replies 28 participants last post by  bluebee 
#1 · (Edited)
So I just got a 02 540iA with 103K from a used car lot. The car had no documentation, i did not get a pre-purchase inspection, bought the car based simply on the condition and test drive. Title and carfax are clean for what thats worth.
This car is by far the nicest i looked at. Its hard to beleive its 8 years old. The interior is beautiful, not a scratch, almost no wear, even functioning cup holders. Under the hood is clean enough to eat off. The car has obviously been well loved.
How can i tell what needs to be replaced. I know that if the cooling system is original it needs to be redone but when you look at the radiator area it looks like brand new plastic. Its completly spotless. And its obvious that its not just been cleaned with armor all by a detail guy prior to going on the lot, i've seen lots of those cars. It looks like its never been dirty. What do i do? Should I plan to change it all anyway and risk changing out newer components? Thanks everyone, this board looks great. I was on e46fanatics.com before (2001 330Ci), this board looks like it will be just a big a help.
 
#2 ·
The radiator has a date tag on it, if you can find it.

Does your DMV release names of previous owners? If so, maybe you can get info.

If all the parts are the same age, the first component to fail is usually the expansion tank, which ruptures, and pukes out a good deal of coolant.

If the rad, tank, hoses, and water pump are pristine, with no dirt/grease compared to the rest of the engine, maybe they are new. But if everything under the hood is squeaky-clean, then it's just a good detail job, and you're on your own.
 
#3 · (Edited)
The date tag (if it's OEM) should be on the right side (passenger's side) of the radiator about 6 or 8 inches down. Get a flashlight and read it. It's European format. It's just a paper sticker, so it could be gone. There is a perm. date code, but you might need to pull the radiator to see it.
 
#4 ·
Only 3 items have date stamped on them:
- Radiator: date stamp is usually on passenger's side
- Hoses should have date of mfg on them.
- Fan Clutch date is kind of hard to read in situ because it is behind the fan clutch. Much easier if you remove the Fan Clutch and look at the date.

If you have courage and energy then look up cooling overhaul for V8 by "BlackBMWs" on bimmerforums.

Then Best is to ground the car for a week, remove all the parts in the cooling system for examination. Anything old, order online and replace them.
This way you can sleep well for another 70K or so.
 
#50 ·
The thermostat has a date code as well. I just had the rad expansion tank and fan clutch changed. I had documentation fron the original owner that the tstat and pump were changed. The mechanic said he checked the tstat and it had a date code of 09/09. Document said it was changed in 2010. Which makes sense Not sure where on the stat to look but it's a very reputable indie BMW shop
 
#8 ·
At least you can breath easy knowing the rad has been replaced. Now I wonder about the expansion tank, thermostat, water pump etc..etc..etc.. :D
 
#9 · (Edited)
After performing a cooling system autopsy, I realized a potentially subtle hint which might clue us to whether an expansion tank is OEM or if it has been replaced.

Notice this picture of my old Behr and my new Behr expansion tank visual level indicator.

The OEM indicator is white and has no secondary bulb an inch from the top bulb; while the newer indicator is red and has a secondary bulb.


I don't know the variability of the OEM sticks; but if this holds true for others, then the shape of the stick indicator might give a clue as to whether an expansion tank is OEM or replaced.
 

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#10 ·
I add this xref to help others figure out if they have an OEM radiator.

As I stated in this radiator autopsy, another off-hand way to pinpoint an OEM radiator is the presence of this pin point on the fan side of the radiator, about ten rows up from the bottom, in the center (at the top of this picture).

 
#11 ·
As a public service suggestion, I recommend we "date-stamp" our cooling system parts when we replace them.

This isn't necessarily for us, as we probably will only do the task once or at most twice for most of us; this is for the next guy who owns our beloved E39s.

I don't know how long whiteout lasts but here is my example of date stamping the radiator, surge tank, belts, hoses, etc.

 

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#12 ·
I'm at 100k...I'm basically replacing everything right now! LOL That makes it easy to remember and pass on to the next guy although I'm thinking we'll have the 2001 530i for a long, long time.
 
#13 · (Edited)
Bluebee,

LOL...
White out (or Liquid Paper) lasts a long time even under engine heat.
The reason I use white-out is not for the next owner, but it is for me.
If I replace anything in the engine compartment, I either use Sharpie (which will fade with heat) or white-out.
This way at a quick glance I know how old that particular component is.
 
#14 ·
If I replace anything in the engine compartment, I either use Sharpie (which will fade with heat) or white-out.
I think it's great we think alike in many ways. It's the wiring in our brains, I guess. Thanks for letting me know that the Liquid Paper (aka whiteout) actually works. I haven't replaced much (so far) so I wasn't sure about its longevity.

I don't expect it to stay on the belts all that long (with all the motion). And I was afraid to engrave the fan clutch itself. Plus an engraving would not be very visible. Seems to me it has to be visible from the top of the engine bay to be of any real use.

I'll keep an eye on these and see how long they last. The good news is that we can recommend others do the same; then nobody would have to guess how old their cooling system is.

 
#15 ·
Bluebee,

Don't bother with the belt because although the whiteout looks good now, when it rotates, the smooth surface (yes the smooth and not grooved surface) rolls over the idler and the white-out will be gone in a week.
Belt is usually easy to inspect with a flashlight to look for cracks, so you don't need to "engrave" it.
 
#16 · (Edited)
the white-out will be gone in a week
Hi cn90,

I forgot about that - but I do remember now that the smooth pulleys without ribs handle the white-out side of the belt. And, I do agree that cracks, when they appear, are easy to see.

BTW, having now done a cooling system overhaul, we can sense, as a tracker can sense a wild beast has been in the area, that there are many clues left after a proper cooling system overhaul - some of which you can easily be seen with the naked eye ...

1. What does the date stamp say on the radiator?
- That's your best clue.

2. What color (and shape) is the expansion tank rod?
- See the clue comparison in this expansion-tank autopsy thread.

3. What brand is your expansion tank & radiator?
- If it's not Behr, then it has been replaced.

4. Is there a white or brown pin about ten rows up from the bottom on the fan side of the radiator?
- Apparently only the OEM radiators have that pin stuck in the coils.

5. What clamp is on the radiator and expansion tank nipple?
- Screw clamps instead of the OEM crimp clamps would be a hint.

6. Are the bleed screws brass or plastic?
- If they're brass, that is a clue that the owner went the whole 9 yards.

7. Are the plastic sides of the radiator tank scratched up and down.
- That is a subtle clue, especially in automatics, that the owner wrestled the new radiator into place.

8. Are the BMW logos scratched out on the upper & lower hose plastic and on the outside of the thermostat housing?
- Again, another clue that the parts have been replaced.

9. Are the two push-pins in the upper fan shroud scratched up?
- It's a clue that the fan shroud has been removed (although that can mean a lot of things).

10. Is the o-ring in the expansion tank cap wholly flat or still plump?
- That's a subtle indication of the age of the expansion tank cap.

11. Is the factory black tie wrap missing from the plastic thermostat wiring loom along the line of the upper cooling system hose?
- That's an indication that the upper hose was removed at one point.

12. ? anything else ?

To flesh out this list, do others have any cooling-system-overhaul tracking clues to add?

Note: Here's a re-used pic showing the roller on the flat side of the belt.
 

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#17 ·
No date code on Behr radiators

Hi, I was looking at a few used E39s, trying to determine if they had the original radiators and noticed a few inconsistencies:

In two 2000's, neither had a date code on the Behr label, but one had a bright orange sticker below the Berh label punched with a date code

In a 2002 one, the Behr label had the date code.

Thoughts?
 
#18 ·
More than likely, the cars you saw with BEHR labels with no date code stamped on them were not BMW/BEHR radiators...but the ones that BEHR makes for the aftermarket.

Note that the posts that show images of the dated labels...not only say BEHR but they also have the BMW Roundel plus the 7 digit BMW part nbr on them.

Remember, BMW uses many vendors to make things specifically for them (Siemens, Bosch, Mann, Mahle, BEHR, Lemforder, etc) and though these companies supply BMW with parts...they also make/sell their products under their own name brand.
 
#21 ·
The only missing part of the sticker was the date in the lower right corner.
There are other (perhaps more subtle clues) ...

  • What color (and shape) is the expansion tank rod?
  • Is there a plastic pin about ten rows up from the bottom on the fan side of the radiator?
  • What clamp is on the radiator and expansion tank nipple?
  • Are the bleed screws brass or plastic?
  • Are the plastic sides of the radiator tank scratched up and down.
  • Are the BMW logos scratched out on the upper & lower hose plastic and on the outside of the thermostat housing?
  • Are the two push-pins in the upper fan shroud scratched up?
  • Is the o-ring in the expansion tank cap wholly flat or still plump?
  • Is the factory black tie wrap missing from the plastic thermostat wiring loom along the line of the upper cooling system hose?
 
#24 ·
Anyone here running the thermostat with aluminum housing? Can anyone recommend it? They aren't cheap but when my next one goes bad I may consider it. Replaced the original at 80k and now at almost 160k miles.
 
#25 ·
If I had a six, I'd run the aluminum housing. The only complaints I've seen about it here involve sloppy casting--nothing that wasn't addressed by the You Tube video discussion that you commented on in another thread.
 
#26 ·
Wow. Feedback from the man himself! Many thanks Bob :thumbup:!

p.s. The only one I'm aware of is the Zionsville. Are there other versions of the alum housing?
 
#28 ·
my cooling system was replaced by the first owner just a few years after it was brand new... in 05... ive got the tank in my hand for this weekend... but ill be doing the rad also in the next few months..

then ill be eye'n that aluminum setup i can easily justify a grand for a rad and tank that will outlast us all...
 
#29 ·
so what is the purpose of that plastic pin in the radiator fins????

few days ago i was shocked that some foreign plastic is stuck in the fins. to my horror it wouldnt come out so i got off the top (tiny bit of the plastic end still in there) and it stressed me out a ton because i spend a ton to refresh my suspension and cant spend another grand to redo all the coolant components....

this piece freaks me out considering the "fragility" of the oem radiator....
 
#30 ·
so what is the purpose of that plastic pin in the radiator fins?
Dunno. There 'was' a thread specifically on that pin somewhere. Somebody came up with the suggestion it's some sort of factory inventory code.

It's not on the replacement radiators; so, for us, it only serves as a reminder of an original radiator (something very dangerous at this point in time of the E39 build cycle).

this piece freaks me out considering the "fragility" of the oem radiator....
Why? It's not functional.

In fact, the aluminum part of the admittedly fragile Behr/Nissens radiator is actually quite robust. See details here:
- Behr radiator and Behr/Heat expansion tank autopsy (1) (2)

 
#31 ·
Here's another date-stamp clue from this thread today:
- E39 (1997 - 2003) > Genuine BMW Expansion Tank

Notice z168's BMW expansion tank has the date code and the aftermarket one doesn't. The date code is the round circle with the '10' inside -'2010'. The dots around the edge of the circle represent months - 8 dots = August. The machine operator adds a punch mark in the mold at the start of each new month. So, this tank was manufactured in August of 2010. The tank from gibo58 was manufactured in November 0f 2009. This allows for trace-ability of defective parts.
 

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