Radiator experts - Need help identifying a nipple :)

My 98 540i6 has a coolant leak. I still haven't found it, but in the process of taking apart the system to look for the leak I snapped off the nipple that holds the small hose connecting the radiator to the expansion tank. The nipple is located on the driver's side of the radiator and the hose it holds runs to the top of the expansion tank on the passenger side. After swearing up a storm and confusing my kids, I originally thought the nipple was part of the radiator and that my 'fix' had turned into a $200 'upgrade.' When I was looking for the parts, I came across p/n 99000003352 which looks like it could be the part I broke. Not sure if that is a BMW p/n. I found it on the autohaus website. I would love for this to be a $2 repair instead of $200, even though I know I will be replacing parts of this system soon. I have 68k miles. Anyway, this is what the part looks like.



Can anyone tell me if I have the right part and if it is in fact not part of the radiator? I tried popping off the remainder of the nipple on the radiator, but it's late and I'm home alone with the kids. Any help is appreciated.

Unfortunately, Realoem shows it as either part of the rad or part of the expansion tank - depending on which end you broke. i.e. there is no seperate part number, so you will probably not be able to get a replacement part from BMW. If you can get the autohauz thing to work, then that's a good thing.

http://realoem.com/bmw/showparts.do?...35&hg=17&fg=05

Here's the TIS look at the Rad. & Expansion....I don't see that part..

Damn. Well, thanks for the help.

Originally Posted by Captngeetch

Here's the TIS look at the Rad. & Expansion....I don't see that part..

What program is that? Does it show more of the E39?

You have the correct part. I replaced my entire cooling system last year. I know BMW radiator leaks all too well.

*******>********>

99000003352

BMW (OE)

Radiator Vent Hose Fitting Nipple

If you have not found you leak yet....check for very small hairline cracks around the neck of the upper hose fitting. (on the same side as where you broke the nipple off). Also, vertical cracks develop between the area where the aluminum radiator clamps to the plastic tanks on the side.

If you are handy, you can replace the radiator yourself for much less than the dealership. It is a fairly easy DIY. I recommend doing the Water Pump, thermostat, hoses, and belts, while your at it. It will still cost you way less and save you trouble in the long run.

Originally Posted by dUMpEdE39

What program is that? Does it show more of the E39?

It's BMW's TIS (Technical Info. Sys.) Shows every part of just about every series.

Originally Posted by AZ-528i

You have the correct part. I replaced my entire cooling system last year. I know BMW radiator leaks all too well.

If you have not found you leak yet....check for very small hairline cracks around the neck of the upper hose fitting. (on the same side as where you broke the nipple off). Also, vertical cracks develop between the area where the aluminum radiator clamps to the plastic tanks on the side.

If you are handy, you can replace the radiator yourself for much less than the dealership. It is a fairly easy DIY. I recommend doing the Water Pump, thermostat, hoses, and belts, while your at it. It will still cost you way less and save you trouble in the long run.

I ordered a new radiator, hoses and the nipple from autohaus. I ordered the Nissens radiator. Is it possible that the Nissens requires the separate nipple, but the OE has it built in? It was dark, but it looks to me like the nipple on my existing radiator is part of the radiator itself. Do you remember how the nipple secured to the radiator? Is it a turn and pull, just a pull, or something else? If I can replace the nipple only, I don't want to destroy the radiator trying to remove the nipple. My 540i is the pre 9/1998 version. From the autohaus website, it looks like there are several versions of the radiator depending on build date and transmission.

I'm going to put the radiator in myself. I've replaced one in my corvette and it was fairly easy. The car already had the water pump replaced under warranty so I'm hoping that will last a while longer.

Originally Posted by Charlutz

I ordered a new radiator, hoses and the nipple from autohaus. I ordered the Nissens radiator. Is it possible that the Nissens requires the separate nipple, but the OE has it built in? It was dark, but it looks to me like the nipple on my existing radiator is part of the radiator itself. Do you remember how the nipple secured to the radiator? Is it a turn and pull, just a pull, or something else? If I can replace the nipple only, I don't want to destroy the radiator trying to remove the nipple. My 540i is the pre 9/1998 version. From the autohaus website, it looks like there are several versions of the radiator depending on build date and transmission.

I'm going to put the radiator in myself. I've replaced one in my corvette and it was fairly easy. The car already had the water pump replaced under warranty so I'm hoping that will last a while longer.

You showed the right part. About $2 at dealer.

http://bimmerboard.com/forums/posts/199986

I wrote this for 98 528i but your 540i is similar. Order the parts (rad, wp, tstat, fan clutch fan blades etc) and you might want to have this extra part (the nipple) just in case. Or work on a Saturday when the dealer is open in case you need parts.

There are more to the cooling system than the WP and thermostat.

Go over the write-up in detail, if I were you, I'd do the entire cooling system, you drive and sleep better.



98 528i

Thanks CN. I actually did a forum search and found your write up a couple of weeks ago when I started looking for the leak. You also steered me to the autohaus site. I think my leak is around the expansion tank somewhere. The first thing I did when troubleshooting was put some more coolant in the expansion tank and it drained right out, but I couldn't see exactly where it was coming from. So I pulled the tank (and broke the nipple) and then tried adding coolant through the hose under the expansion tank. No leak. The tank looks fine though, which has me wondering if it was something as simple as the expansion tank level sensor working itself loose. My plan is to put in the new radiator and new hoses and fill it up to see if I can replicate the leak again. Thankfully, pressurized systems show the leaks fairly fast.

BTW, I demolished one of the small clamps that BMW uses on the smaller diameter hoses. Is there a reason that they use those pin/slot clamps rather than the regular screw kind? I was planning to just get the screw kind when I put humpty dumpty back together again.

screw clamps are fine. I am not sure why they use those other abominations. You can also solve the common PS leak by replacing those clamps too.

If you have a leak on your expansion tank, it is typically at the very bottom of the tank where the level sensor is mounted. Been there done that last year. It starts as a small drip.

Originally Posted by Charlutz

Thanks CN. I actually did a forum search and found your write up a couple of weeks ago when I started looking for the leak. You also steered me to the autohaus site. I think my leak is around the expansion tank somewhere. The first thing I did when troubleshooting was put some more coolant in the expansion tank and it drained right out, but I couldn't see exactly where it was coming from. So I pulled the tank (and broke the nipple) and then tried adding coolant through the hose under the expansion tank. No leak. The tank looks fine though, which has me wondering if it was something as simple as the expansion tank level sensor working itself loose. My plan is to put in the new radiator and new hoses and fill it up to see if I can replicate the leak again. Thankfully, pressurized systems show the leaks fairly fast.

BTW, I demolished one of the small clamps that BMW uses on the smaller diameter hoses. Is there a reason that they use those pin/slot clamps rather than the regular screw kind? I was planning to just get the screw kind when I put humpty dumpty back together again.

The small clamps from BMW is a "quickie" type clamp, designed for quick assembly line's efficiency to save money.
Nothing wrong with it except when it comes time to repair, people put a real clamp in. Get these screw-type clamps at dealer for 80 cents each etc.

If I were you, I'd do a complete cooling system overhaul.
At 64K, your cooling system (especially 540i) lives on borrowed time, seriously.

Let say you replace 3 items (radiator, reservoir, hoses), the other items (belts, tensioners etc.) will catch up with you shortly and you will be back in there taking apart the same items you just did.
Do a complete overhaul, it will cost you a bit more in parts but you save the labor (and agony) of going back there later; you will sleep well at night and on long distance trips, no worry

I realize this is an old thread; but I'm researching the radiator nipple mishap problem and Max at OEMBimmerparts and cn90 together devised a nice non-destructive radiator nipple removal procedure that we need to be cross linked into the record for the very next person to test and report back upon:
WANTED: An ingenious method of removing radiator nipple