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5 Series DIY
Knowledge Is Power! ~ The place for do-it-yourself threads on a variety of topics. Start a thread describing a particular job (oil change, cooling system overhaul, brakes, shocks and springs, etc.) or search for one you need help with!

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Old 06-29-2012, 07:44 PM
magusat999 magusat999 is offline
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Location: Oakland, CA
Join Date: Jun 2012
Posts: 24
Mein Auto: 1994 BMW 525i
I was tricked by Sears today - the website said they had the fan clutch wrench and the tool in stock at my store. i walked two miles to the store abd they didn't have ANY 32mm wrenches of any sort whatsoever, much less the other tool. I was SOL and needed to do this today, so I picked up the thinnest adjustable wrench I could find. I wanted a slide wrench, which would have made it even thinner, buy they had nothing that opened to 32mm (there was a tag that said "see sales associate" but the sales associate said that means its out of stock - she even suggested I order it... why would I go to a store to order something online? I could have done that in my underwear at home!)


All they had that was thin enough was a 10 inch adjustable wrench. I said some prayers and placed it in the fan clutch nut and began to apply pressure. It slid in without touching the surrounding components, I heard the nut break free and that was it - fan is coming off! I imagine it would be even easier with a longer wrench - I had just enough room to get mu two fore fingers and thumb on it. The wrench cost me 18 bucks. Maybe if you aready have a thin wrench it might not be necessary to buy a special tool - just make sure your not forcing it in the space.
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Old 09-13-2012, 05:52 PM
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bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 20,349
Mein Auto: 02 BMW 525i M54 auto 130K
So these tips and tricks don't get lost, here's one posted today:

Originally Posted by Adamcan2 View Post
Two weeks ago I did a cooling overhaul for my 530i with 123,000 miles on it. I bought a bundle from OEMBimmerparts.com that included:

Nissens Radiator
Expansion Tank
Graf Water Pump w/Metal Impeller
Wahler Thermostat and Housing
Upper and Lower Rad Hoses
Cooling Temp Sensor
a small washer in its own bag

This bundle cost around $430. I spent an evening pricing things out from different suppliers, figuring out what the cost individually would be, etc. It looked like I could have saved about $10 if I sourced all the parts separately, but I was happy to the extra $5 for the convenience of having everything put together and shipped at the same time. In addition, most of the best individual prices that I found were on eBay which is always a bit of a crapshoot.

The day of my fix, I also decided that I should change the Serpentine Belt. This part costs $30 online, but since it was day-of I went to the stealer and paid $61.86. Oh well, better than worrying about it.

I primarily used cn90's excellent DIY for the fix, which can be found here: http://www.bimmerboard.com/forums/posts/199986"]. Besian also has good information about the fan shroud removal at http://www.beisansystems.com/procedu..._procedure.htm. I have heard that Pelican Parts has a good DIY as well but I did not use it. Because there are such great resources out there for this fix, I will not go into it step by step, but will put down a few details that I ran into. I also did the double Vanos during this fix, but I will put my specific experiences on that in a different post.

I recommend getting the serpentine belt and A/C belt if you are going to do this fix. If you plan ahead (unlike I did) you can have both for around $40, and again, peace of mind is why we do these fixes. You will be removing both of these during the course of the work, so it is no extra effort to replace with new.

Another item is the catch pan for coolant. I wasn't sure what size I needed. I ended up using a Rubbermade 3 gallon rectangular container. I only ended up draining about 1.5 gallons of coolant, but to be fair a good amount ended up on the garage floor. I also cleaned this puppy thoroughly after use. Since I had an issue with my fix I had to open everything up again, and having a clean container meant that I could re-use the new coolant when I had to drain it for the second time.

You will need a 32mm wrench for this fix as well. I bought one at a local bike shop for $12. This is also the wrench you will need if you want to fix the headset on your bike. Hooray, double use! I think I saw some posts that said they got away with using a wrench, and while I am sure this is possible, my life was made much easier with the 32mm. Also, if you have a choice of lengths when purchasing this wrench, get the longest one you can find. Mine was a bit short which makes it awkward to smack with a hammer, but even so it is not too bad.

Moving on to the fix, the first item that I was not clear on was how the radiator plug works. It is on the bottom of the radiator on the drivers side, and I guess it is usually blue (mine was). I turned it 90 degrees, as specified, and nothing happened. What you have to do then is pull straight down on it. It will pop out with moderate force, and you will get coolant all over your shirt. Or at least that is what happened with me. If I knew better, I would have positioned myself more out of the way and yanked more firmly. Then I would have only gotten it on my hand. You will get it on your hand.

The second item that gave me a bit of trouble was the hoses themselves. They are held on with a metal clip that is easy to pry up, but even after doing that the hoses can be difficult to dislodge. I wasn't sure if I needed to do something else or not. I did not. Just pull up the clip (half of them will fly off the hoses, but this is no big deal) and start to work that bad boy off. The first hose you take off, the one that connects to the auxiliary water pump, will spray quite a bit of coolant out even after draining the radiator, so be prepared. It comes out with a small amount of pressure so factor that in with your catch pan positioning.

Once you follow the directions and get the fan shroud loose, you get to the dreaded fan removal. I have removed this thing several times now, and it has been different every time. I assume it is because the fan is "clutched", so depending on the clutch position the fan may spin easily or it may not spin much at all. At any rate, the method described is exactly right--put the wrench on and hit is with the hammer. It is reverse threaded so you want to go righty-loosy. A snap of the wrist is better than a wind up power shot. You don't need power, you need pop. Two out of the three times that I removed the fan I popped it and then spun the fan to remove it, but the other time I couldn't spin the fan and had to use the wrench the whole way. It sucked, but it worked. I also had some trouble lining up the threads when I went to put the fan back on. Just keep at it, and know that this part is (normally) the biggest PITA in the whole project.

When I got to the Serpentine belt I was having some trouble removing it. The DIY says to use an allen wrench in the middle of the tensioner pulley to release the tension. I did not have a wrench that would fit. What I did find was a 16mm (I think) bolt head cast into the tensioner arm. I was able to use this to release the tension. It seemed easier to me than working with the rather small hole in the middle of the tensioner pully. The only other detail here is that when you release the tension the instructions are to put a drill bit into the holes that line up above the tensioner pulley to keep the belt slack. This works well, but you definitely want to put in the largest drill bit that will fit in the hole. I started out with a drill bit one or two sizes smaller than the hole, and that half millimeter made it so I couldn't release the belt.

Another issue that I ran into was the coolant temperature sensor that goes on the lower radiator hose. It didn't feel tight when I put it in, and I had this washer in a bag all by itself for which I did not have a purpose. Since the washer fit into the socket for the sensor, I put it in and replaced the sensor. I must have pushed too hard because I broke the housing of the sensor. It didn't leak any more, but I was throwing the code for that sensor--sorry I can't remember what the code was. I ended up buying another sensor and installing it without the washer, and no more code.

My last issue outside of the DIYs was that once I buttoned it all up, I was getting coolant leaking from behind the serpentine belt. I couldn't tell if it was the thermostat or the water pump. I posted a question about it on this forum and got many helpful suggestions, but the reality was that I made a mistake. I have a $20 torque wrench that is a POS. It is one of the beam-style ones. When I was replacing the Vanos during this fix, I broke a post from torquing it too hard, because to my eye the torque wrench had not reached the recommended N/m. Because of this I was way too careful when I installed the thermostat, and didn't bolt it back in strongly enough. When I finally inspected the thermostat I could turn the bolts with my fingers! I torqued this back down and everything was fine.

Based on my experience I strongly suggest getting a digital torque wrench. Sure, it costs $100 or more, but if you are a DIY person, tools don't cost you money, they save you money. Add that onto the fact that you will use this tool with nearly every fix you do, and the $100 seems pretty worth it.

To finish, a quick question: what is that little washer for? While it fits in the temp sensor socket, the bottom of the sensor is pointed rather than flat, so it doesn't seem like it is made for that application. With the new sensor that I put in without the washer I am getting random droplets of coolant leaking out. Not much leakage--maybe 2-3 drops on a 10 mile journey--but it seems the seal is not as good as it should be. Is that actually what the washer is for? Was I just being too much of a boy when I shoved the first sensor in and broke it?

Thanks to everyone for their posts and DIYs. This was a fun fix and I am feeling much better about my cooling system. I am running consistently 93 degrees C on the high cluster and I can just tell my car is much happier.


Update: Drat. My cooling system sprung a leak yesterday!

Originally Posted by bluebee View Post
Well, it's 'my' turn again!

I noticed a puddle on my driveway today ...

So I started looking for the telltale white spots:

And, watching for a while, I found the culprit!

Note: I last replaced my Behr expansion tank in 2010 as noted by the markings on the side.
Each repair should invariably add to our knowledge base by the process of inexorable incrementalism.
Your job, in return, is to read the suggested threads, where the best people will always add value to those threads, either by pictures or by descriptions, so the next person with the same problem stands on your shoulders.
See also: E39 Bestlinks & How to easily find what you need
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Old 10-14-2012, 12:06 AM
ndube ndube is offline
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Location: Phoenix
Join Date: Jun 2012
Posts: 7
Mein Auto: 1999 BMW 540i 6-speed
Originally Posted by cn90 View Post
COOLING System Overhaul Info for V8 folks


Last year I wrote the Cooling Overhaul Tips for Inline 6-cylinder engine (1998 528i):


For V8 engine, it is very similar in concept in belts layout, see this diagram that I just prepared for you folks with V8 engine. When combined above link and this picture, V8 folks should be able to do cooling overhaul themselves

98 528i 5sp 95K
One note on the picture: V-8s built after September 1998 have a 3d roller outside between the power steering and alternator pulleys. I'm in the process of pricing and ordering parts for a complete (front) overhaul of the cooling system next weekend after discovering a small leak around the expansion tank top.
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Old 12-09-2012, 08:51 AM
5seriescrissy 5seriescrissy is offline
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Location: USA
Join Date: Dec 2012
Posts: 1
Mein Auto: 2006 525i
I am having coolant problems as well. I have a 2006 525i with 85K miles. The coolant light started coming on and I was having to top the system weekly. Now it is daily and I was just adding water. I was just advised that water is a no no and I must use coolant. Unfortunately, I just lost my job and there is no cash to make expensive repairs.

Does anyone have any diagnostic tips? Back in the spring,l I had a dealer check it out and they could not locate the problem. However today after speaking with someone at an auto supply store, We looked under the hood and it does appear there are some fluids in the underbody of the vehicle.

Thanks for any assistance you can provide!
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Old 01-04-2013, 03:16 PM
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bin01123 bin01123 is online now
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Location: Atlanta, GA
Join Date: Dec 2010
Posts: 213
Mein Auto: 2001 540i 6 Speed
I just completed a cooling system overhaul on my 01 540. I replaced the water pump, thermostat, belts, tank, hoses, and radiator. I put BMW coolant back in with a mix of distilled water. The car run a little rough on startup now but smooths out. Has anyone had this kind of an issue after a cooling system overhaul or any ideas?
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Old 08-21-2013, 02:32 PM
dragon6971 dragon6971 is offline
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Location: Delaware
Join Date: Jul 2013
Posts: 26
Mein Auto: 2000 540i, Black on Black
I will be joining the coolant leak club now. I have a 00 540i, that has a mysterious coolant leak. no one can find it. It has been tested hot and cold. all i know is that the leak is leaving residue all on the drivers side of the engine compartment from the upper hose, on the fan side, to all over the oil filter cartridge mounted on the fender. It started out slow but has progressively gotten worse. Still no one can find the leak. i have looked every where my self but again found nothing. The radiator is super clean with no residue. The tips of the fan do look as if they have a slight residue on them. The small puddle that keeps appearing is on the driver's side under the fog light on the ground. Any help that can be offered is greatly appreciated. I, for one, am at a loss. Thanks in advance.... Also any advice in possibly upgrading the entire cooing system, (parts and where to get them, as well as, price if possible) would be a welcomed addition too.

Last edited by dragon6971; 08-21-2013 at 02:37 PM.
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Old 08-21-2013, 02:50 PM
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Ågent99 Ågent99 is offline
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Location: Bay Area, CA
Join Date: Jan 2002
Posts: 5,931
Mein Auto: Trek 6500 MTB
Read the thread and check the links...all info is there. As to locating your leak, I suggest cleaning the engine real well and letting it dry thoroughly. Then run it and see if you can located the leak. Have you had a pressure test done? That might help locate the leak as well. All that said, if you have ~100k on your original coolant system parts, just seriously consider having all of them replaced.
2001 530i/5 (E39), Topaz Blue/Stone Green/Black (118k miles) *very rare interior/exterior color combo*
2005 545i/SMG (E60), ED Order, Titanium Grey/Grey (lease over)
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