Broken bleed screw culprit

Found the source of coolant spray. Looked like dirt initially, but yes, it's a leak:



Went out for a bit and got the car real warm (not hard on a 100-degree day) and came back home, parked in the garage and smelled the coolant. Heard some hissing (air) and localized it to the bleed screw. Seconds later, found the crack.



So, am I seeing this piece as an assembly when ordering the hose?



EDIT:

Oops...notice that long crack! Plastic here? WTF?



Anyone here a fan of JB Weld until the new hose/assembly arrives?

No No No, No JB Weld and all that crap.

Time to do a cooling system overhaul:
http://www.bimmerboard.com/forums/posts/199986

Man, you are a lucky man!!! This thing could have blown up in a hwy far away from home.
This is why you need to do a cooling system overhaul.
You have been sitting on a time-bomb.

Options:
1. DIY as in the link above
2. Get a shop to do the cooling overhaul.
My cousin runs BMW shop in Gardena, some 40 min from Dana Point CA.
South Bay Independent BMW Service, Gardena, tel: (310)532-3145

Just read your write-up twice today (as you've posted to others). What a coincidence.

Why a complete overhaul at this time? Do all of the components go bad at about the same time? Or is it a matter of the system being down for repair?

You will find no end to the posts extolling the virtues (tongue firmly in cheek)of the BMW cooling system. There are surely other parts jealously awaiting their turn to spray coolant around your engine compartment.

Some guys don't seem to like the idea, but the plastic weld type products work great for a temporary fix. It took a while for Zionsville Auto to make a new radiator for me, so I ended up using that on mine to get me through. It worked perfectly and didn't leak a bit.

Rodolfo,

An analogy is your garage door at home. Let's say it is 20 years old. And remember each part has its own lifespan. You replace the motor; 3 months later the chain breaks, 2 months later the spring breaks, 1 week later then the cable snapped, then the door rail fails. Then the bearings go. Then the door breaks. So it is better to change the whole thing than bits and pieces!!! Cheaper and more efficient this way. But if your budget is tight, you need to be mechanically inclined to handle it.

-----------
You should think about the cooling system as a "soccer team" with many players: missing one player, you are in trouble!!!

The problem is: some parts in the cooling system give you warning and some are "time-bombs". The plastic crack is classic, plastic becomes brittle with time and heat and the underhood environment is "perfect" for that.

SOME WARNING vs NO WARNING LIST

- WP leaking slowly or seized suddenly, taking the belts and fan blades with it....see recent post by "matt24"

- fan clutch usually failing slowly...so you may elect to wait a bit.
- fan blades can crack and fly off suddenly taking the underside of the hood with it....BIG BUCKS

- reservoir can crack slowly or suddenly
- Hoses can leak slowly or can blow suddenly
- Tensioners fail slowly causing belt squeal (not enough tension) and belts slip.....
- Rollers fail slowly and make noise, giving warning. BUT......many of these components sit under the hood and when they make noise due to failure, the noise can be hard to notice.

- Thermostat housing is plastic and at 80K is overdue, it can crack suddenly and in 30 seconds, you have an overheated engine.

The bottom line is to replace the parts that fail suddenly because there is virtually no warning at all, leaving you stranded.

A Cooling Overhaul is not all that bad, Parts cost $550 and one full Saturday, your labor. You will be glad you do it. After all, this cost is minimal compared with the value of your car.

This is approx. lifespans for cooling system components. Take this with a "grain of salt":

RADIATOR:
540......40-60K
528i...... 80-100K

HOSES: 10y/80-100K
BELTS: 60-70K
FAN BLADES 10y/80-100K...Plastic degrades with time and heat, the underhood environment is "perfect" for this

FAN CLUTCH: 90-150K
THERMOSTAT: 60-70K
THERMOSTAT HOUSING: Plastic 80K max; aluminum 120K or so

RESERVOIR+CAP: 80-100K

WP: 80-120K (We have seen failure as early as 30K but this is rare)

So, figure it out, what has been replaced..keep them; what is overdue replace them. Do NOT wait for disater on the hwy (+ inconvenience to your family).

Remember one thing: mechanics tend to fix only what is broken and leave the rest alone. They rarely think "global and pro-active".
On the other hand, aircraft maintenance is very different: at fixed intervals, certain parts are replaced. They take no chance.

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But if you are tight on budget (and provided that you are mechanically inclined and DIY; otherwise repeat trip to shop costs even more), then do the BASIC MINIMUM: Rad + Reservoir/cap + WP + Hoses + Tstat/Tstat Housing + Belts.

The tensioners fail slowly....so they can wait. The rollers (3 of them) can be repacked with grease and re-install.
(the tensioners x 2 are $95 for both, the rollers are $100 for 3 of them....so you save $190 or so, but you need to watch them every 3 months or so....listen for squeal and check the play in the rollers).

Yesterday I drove 450 miles in the middle of nowhere in Iowa in 110F heat, I will tell you having a overhauled cooling system gives you so much confidence that this car will not let me down. If you drive around town only, then do the basic minimum as above.

HTH

Thanks for taking the time to explain all that to me. I'm a DIYer so this is within my skill-set. This car is indeed my highway cruiser as I take it back and forth from Vegas to OC on the weekends so I definitely don't want to be stranded somewhere in between LV and Barstow, etc..I've been there/done that in a FIAT and had to devise half-a$$ed roadside repairs to get home. Not taking chances with this car. Thanks again - yes, it helps.

Which water pump?

888010330
EMP Stewart
Water Pump; High Performance
This pump offers 20 percent flow increase, carbon graphite seal, larger bearing, and stainless steel impeller for improved cooling efficiency. Please be sure to check thermostat, radiator, and all hoses for condition to optimize cooling benefit of this pump. Special order item - limited availability. $250.00 $179.95


11511722536LA
BMW (OE)/OES
Water Pump; Original Type With Plastic Impeller
1 per car. $96.75 $75.69


11511722536Z
Graf
Water Pump; Update Replacement with Metal Impeller and Gasket
1 per car. $83.25 $60.18


I can't spring for the stainless steel impeller so that one is out..

Use either:
1. BMW OEM
2. HEPU waterpump. My HEPU is now 16 months and 15K miles later: rock solid, not single drop of leak. The detail is in my write-up.
My Nissens radiator is also holding up nicely no leak.

(Graf is prob OK, I used Graf in my 1983 735i 5spd E23).

It is a waste of moeny to buy Stewart WP.

The bottom line is that you replace the WP every 70-90K miles, so who really cares what brand, as long as it is BMW or HEPU.

Review of service records, anything not done and past due then change it. Anything reasonable, you can keep it (like the rollers that need grease). Anyway better to have new parts, you drive long distance with peace in your mind, which is worth millions dollars....

HELP! HELP! HELP!

So my "check coolant level" warning came on a few days ago and I decided to be lazy and continue driving as is...I delayed purchasing coolant for another day until last night my engine started to overheat while I was on a date! I parked the car and opened the hood to cool the engine. Fluid was blowing out as high as the hood was open through the bleeder screw next to the expansion tank. It eventually stopped where I let the engine cool for 2 hours then filled a gallon of distilled water in the expansion tank so I can get home. I purchased coolant today to fill up and bleed the system and noticed that the bleeder screw next to the expansion tank was missing the screw head while the rest of it was broken inside. I'm thinking of slowly carving a small groove in the broken screw with a flat head so i can unscrew it out till I purchase another screw on Monday from the dealer. Now here are the questions I am left asking myself...

1. Has this situation caused anymore damage such as a leak somewhere in the hoses or connections or did the fact that the bleeder screw broke cause a pressure relief in the system thus not blowing the head gasket or any other connections.

2. Assuming nothing else broke, since I filled the tank with a gallon of distilled water should I drain the cooling system before adding a new 50/50 coolant mix or can I just top it off and continue with the bleeding process?

3. On a scale of 1-10, how stupid am I for allowing this to happen? I apologized to my car like a 100 times for putting it through this mess.

Originally Posted by maredferrari

So my "check coolant level" warning came on a few days ago and I decided to be lazy and continue driving as is...
I delayed purchasing coolant for another day...

Originally Posted by maredferrari

3. On a scale of 1-10, how stupid am I for allowing this to happen?

I think if you go back and read the first quote, you get the answer to your question, and any further comments are superfluous.

You now face the problem of whether you've blown your head gasket, or worse, warped or cracked your head.

As for your immediate problem, it's hard to tell how much coolant you have left. I'd try refilling with undiluted coolant and see how much you get in so that you can run the engine for diagnostic purposes. If your engine is still intact, then plan on replacing other components of your cooling system. There are many threads on this, and cn90 has covered it in detail in lots of them.

Originally Posted by RMMJ

Why a complete overhaul at this time?

I realize this is a resurrected old thread, so, for future reference, I'll just point the user to the pictorial thread on what actually breaks on our cooling system.
- Pictorial look at typical E39 cooling system failure modes (1)

I'll also add the three pictures above, annotated, and shrunk, to that thread so that others benefit from the nice pictures.

Originally Posted by RMMJ

Which water pump?

This thread wasn't available at the time, but I'd refer others to it now:
- What brand of waterpump to buy (1)

Originally Posted by maredferrari

Fluid was blowing out as high as the hood was open through the bleeder screw next to the expansion tank

Happens all the time. See this thread for details on bleeder screw mishaps & solutions:
- How not to bleed your E39 cooling system (1) (broken bleeder screw solutions)

Originally Posted by maredferrari

Has this situation caused anymore damage

You'll need to do a few tests to make sure:
- 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)

Originally Posted by maredferrari

should I drain the cooling system before adding a new 50/50 coolant mix

Hmmm... Seems to me you're due for a cooling system overhaul. In doing that cooling system overhaul, all the fluid will drain out anyway (when you replace the waterpump, for example). So, you'd replace all the coolant (which you'd replace every five years anyway).

In the interim, Bob's suggestion seems apropos.

Originally Posted by maredferrari

On a scale of 1-10, how stupid am I for allowing this to happen? I apologized to my car like a 100 times for putting it through this mess.

If your engine is actually blown, I'd put you (literally) at 28th in this list (but it doesn't 'yet' sound like your engine actually 'is' blown):

- Real-world results from people faced with cooling-system caused blown engine problems (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).

Originally Posted by bobdmac

any further comments are superfluous.

Drat. Now you tell me. After I already laboriously typed all this up!

Originally Posted by bobdmac

You now face the problem of whether you've blown your head gasket, or worse, warped or cracked your head.

Living vicariously, here's what others have done in this situation:
- Summary advice to provide users who suspect a major engine repair due to overheating (1)

Originally Posted by bobdmac

plan on replacing other components of your cooling system. There are many threads on this

Here is the short list that answered most of my cooling system overhaul questions:

- 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) & 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) & 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).

Can someone tell me the size of the Bleeder Screw?

Originally Posted by jcvara

Can someone tell me the size of the Bleeder Screw?

If it's not in this bestlinks thread, then it should be asked there so as to keep it all together:
- The UNOFFICIAL Brass Bleeder Screw Thread

Hi Blue Bee, sorry if my question is not in the correct part of this thread etc, but i need to ask some questions re the bleed screw. As i turns out it was not clear oil around my expansion tank, it was coolant, my garage is dark and i was in a rush.......I located the cause of the leak, it was leaking straight out of the top of my Expansion Tank Screw!! Right through the center of the cross.
Do you have any idea what causes that to happen? Is it a failure of the screw or is there a block somewhere else in the cooling system?? Its all confused me a little as obviously i know there is a hole in the screw, but it has never leaked from there before. I tightened the screw a little and that made the leak worse, so then i loosened the screw and it didn't help, and then, yep you guesses it, i broke the head off the the Bleed Screw. Not to worried, i have read the threads and can remover the rest of the screw, i think.......
But my main question is, what has caused the coolant to leak straight out of the top of the Bleed Screw, and would just replacing the bleed screw with a new one fix it, or is there a block which has caused excess pressure to build up??