Forget the brass bleed screw!

Gentlemen and ladies,

If you have :

1. Purchased and are currently using a brass bleed screw.
2. Considering purchasing and using a brass bleed screw,
3. About to advise somebody else to purchase and use a brass bleed screw,

Halt !

The thing expands when heated and causes plastic deformation to the bleed socket, which causes it to get loose over time permanently and then you'll find one day that you can't tighten your bleed screw into the socket.

This just happened with a new radiator on an E34, that's about 18 months old.

It is also probably what was responsible for my old bleed socket's failure, leading to me changing the radiator itself about a month back (which I didn't mind all that much actually coz it was a fun DIY and I chanced upon the outstanding properties of high temp silicon window, but I digress). I had been using a brass bleed screw for around 2 years. When the socket went, I thought that I must have stripped the threads somehow. I wondered how I did that considering that I never tightened it to absolute tightness and I knew that wasn't the objective. It had been getting loose over the past few months.

The bleed screw costs $8 shipped and will eventually cost you $150-$200 for a new radiator aside from any installation charges.

Here's a useful test if you're using a brass bleed screw. Take out your old stock plastic bleed screw and try screwing it into the socket. It will be much looser than you remembered it to be when you first replaced it with the brass one. There you go.

If you have trouble screwing in the oem bleed screw, wrap it a couple of times using white pvc pipe tape. If that doesn't work, then apply the abovementioned silicone sealant as well.

Its not a good idea to keep your brass bleed screw in there either in the hope that as long as you don't remove it, you're not going to have a problem. Multiple cycles of expansion and contraction will stress an already old radiator's bleed socket. Look what it did to a mere 18-month old Behr radiator.



rgds
Roberto

I have had no problem with mine .I could see it being over tighened and stripping the threads out. The reason to go to metal was the plastic bleed screw would break up from age and useage.

How many times have you fiddled with the bleed screw in 18 months in order to get it to fail?

That is clearly operator error.

Originally Posted by luckydog

I have had no problem with mine .I could see it being over tighened and stripping the threads out. The reason to go to metal was the plastic bleed screw would break up from age and useage.

LD, after the first time anyone tries to screw in a bleed screw and realises that it can keep turning and turning as you apply force, you intuitively learn to stop much earlier when it feels just tight. So there will be no stripping of threads through stupid use or excessive use of force.

And remember, this is now happening to a mere 18-mth old radiator. Now that i've identified the cause, it makes sense because i never tightened it on my old radiator that much, even though I flushed it etc several times, and I took care to do it slowly in order not to flatten the o ring on the brass screw out too much, and I was wondering how I could have stripped the threads.

That clearly wasn't the cause. I still recommend that you change your bleed screw to a stock one. Spray paint it brass if you must but please get rid of the brass bleed screw.



rgds,
Roberto

Originally Posted by snowsled7

how many times have you fiddled with the bleed screw in 18 months in order to get it to fail?

That is clearly operator error.

+1

Have 2 (two) brass bleeder screws on my car: one on the expansion tank, the other on the upper radiator hose. No issues so far.
Had plastic bleeder screws, and very first time I touched the one on the expansion tank, after a coolant flush, it desintagrated leaving a massive chunk in the threads. That was the end of the plastic bleeder screws saga for me.

Originally Posted by doru

Have 2 (two) brass bleeder screws on my car: one on the expansion tank, the other on the upper radiator hose. No issues so far.
Had plastic bleeder screws, and very first time I touched the one on the expansion tank, after a coolant flush, it desintagrated leaving a massive chunk in the threads. That was the end of the plastic bleeder screws saga for me.

Hi Doru,

I would still strongly suggest that you switch out to a OEM plastic bleed screws. Remember my experiences. Two good used radiators had their sockets ruined and a new one was on its way before we noticed the problem and stopped it. Yes I flush my rad more often then I need to, but I don't strip the threads of my bleed screw when I tighten it down either. And further, BMW did use a plastic bleed screw. Couple that with my observations and I think the risks far outweigh the benefits.

In any case, bleed screws are not supposed to disintegrate. Perhaps the previous owner did not flush your radiator regularly the way he was expected to, at which point he would have noticed any deterioration in the bleed screw and replaced it way in advance. Or perhaps it had been left in there for too long and was not gingerly opened to compensate. Could that be possible ?

Anyway, I believe the bleed screw ought to be replaced every couple of years due to the flattening out of the rubber o ring that it has.

Originally Posted by snowsled7

How many times have you fiddled with the bleed screw in 18 months in order to get it to fail?

That is clearly operator error.

I think we know enough about the bleed screw to not strip the threads even if we flush the radiator every day.

Originally Posted by robertobaggio20

I think we know enoigh about the bleed screw to not strip the threads even if we flush the radiator every day.

So you contend that it is a faulty design? I find that a rather interesting assertion since it seems most of us have never expereienced such a failure. You have seen my list of cars, I have never had a bleeder screw issue in 25+ years. I have flushed a LOT of radiators on a lot of different cars. The design has existed for several decades without problems. I don't think "we" have a problem, but somebody might

Many of us in the E39 forums have had many failures of stock plastic bleeder screws. Mine personally went bad within a few months of replacing the expansion tank. This isn't rocket science. Plastic pieces heat up, get brittle then go to pot. Brass is not subject to that. Good luck op and I'm sure you'll keep a few extra plastic screws on hand for when they inevitably fail. Cheers!

2.5 years and counting on my brass bleed screw. no complaints

A. - Snowy, all of your cars were using the stock bleed screws, not the brass ones, ok ? That's the general assumption. It would be invalid to the argument as you advanced it. Please bear that in mind in debates in future.
- Metal expands more than plastic. Repeated hot-cold cycles could deform stuff around metal especially if that stuff was not designed to anticipate such repeated expansion stresses, which might be the case when they chose to use a plastic bleed screw for that socket instead of a metal one.

B. There's alot of heated plastic in the engine bay and on the radiator, including the tope hose's neck. If it was known to be so brittle (and obviously this was tested), there wouldn't be that much plastic. This is also not rocket science. Nevertheless, the E39 forums' experience is valid. I can only speculate that BMW sent a bad batch of bleed screws their way. Nevertheless, the fact remains that brass bleed screws are being used in places where only the expansion rates of plastic were designed for. Again, not rocket science too. And since this is a pressurised cooling system critical to the engine that we are dealing with, and you are dealing with an older car, perhaps the risks need to be reconsidered, especially in light of my observations.

C. Yes Padre, I understand, and I have not seen this complaint here before. My OP lists the primary facts that I observed, which are not in dispute. We are not pleabians when it comes to the radiators, especially something that we learnt to be careful with in earlier bmws. This was our experience. Perhaps we got a bad batch of radiators, perhaps we got a bad batch of bleed screws. We certainly did not strip the threads, even unintentionally.

Originally Posted by robertobaggio20

A. - Snowy, all of your cars were using the stock bleed screws, not the brass ones, ok ? That's the general assumption. It would be invalid to the argument as you advanced it. Please bear that in mind in debates in future.

What do you know about all of my cars and what type of bleeders they had? Do you seriously want to advance that discussion?

We certainly did not strip the threads, even unintentionally.

So then your threads are not stripped? I am sure that the brass screw didn't strip itself out. There is only ONE way that happens, when human hands are laid upon it.

Who is this "we" you keep referring to. I do not see a single hand raised in agreement. Have you got a turd in your pocket?

They were not stripped. The sockets grew bigger. We initially thought they had gotten stripped because we didnt consider the brass bleed screw as a culprit.

And last time i checked, you were not in my pocket . Read my op carefully and you will know who i refer to in my earlier posts.

Originally Posted by robertobaggio20

Gentlemen and ladies,

If you have :

1. Purchased and are currently using a brass bleed screw.
2. Considering purchasing and using a brass bleed screw,
3. About to advise somebody else to purchase and use a brass bleed screw,

Halt !

The thing expands when heated and causes plastic deformation to the bleed socket, which causes it to get loose over time permanently and then you'll find one day that you can't tighten your bleed screw into the socket.

This just happened with a new radiator on an E34, that's about 18 months old.

It is also probably what was responsible for my old bleed socket's failure, leading to me changing the radiator itself about a month back (which I didn't mind all that much actually coz it was a fun DIY and I chanced upon the outstanding properties of high temp silicon window, but I digress). I had been using a brass bleed screw for around 2 years. When the socket went, I thought that I must have stripped the threads somehow. I wondered how I did that considering that I never tightened it to absolute tightness and I knew that wasn't the objective. It had been getting loose over the past few months.

The bleed screw costs $8 shipped and will eventually cost you $150-$200 for a new radiator aside from any installation charges.

Here's a useful test if you're using a brass bleed screw. Take out your old stock plastic bleed screw and try screwing it into the socket. It will be much looser than you remembered it to be when you first replaced it with the brass one. There you go.

If you have trouble screwing in the oem bleed screw, wrap it a couple of times using white pvc pipe tape. If that doesn't work, then apply the abovementioned silicone sealant as well.

Its not a good idea to keep your brass bleed screw in there either in the hope that as long as you don't remove it, you're not going to have a problem. Multiple cycles of expansion and contraction will stress an already old radiator's bleed socket. Look what it did to a mere 18-month old Behr radiator.



rgds
Roberto

You show me bobby. There is no reference to anyone other than yourself. One could surmise that the 18 mo. old radiator is in someone elses car but it is very unclear.

As I read down, I still do not see a single poster in agreement with you. In fact the evidence seems to support the brass screw as a good thing.

Originally Posted by snowsled7

You show me bobby. There is no reference to anyone other than yourself. One could surmise that the 18 mo. old radiator is in someone elses car but it is very unclear.

As I read down, I still do not see a single poster in agreement with you. In fact the evidence seems to support the brass screw as a good thing.

My apologies then. I'm got a friend in 3D with an E34. We often work on our cars together. One old and one new radiator referred to in my op came from his car and of course the other old radiator (which, come to think of it, was just over 4 years old which isn't all that old at all) was on mine.

Yes I agree that no one else seems to have had trouble with their brass bleeds screws. Be that as it may, it is my advice that the brass bleed screw be abandoned in favour of the stock plastic one. The stock plastic screw does not deteriorate the way the E39ers have experienced, it is simple to manage, you just need to be measured in your torque when you both unscrew it from the socket and when you tighten it back, that's about it. Our experiences are direct observations, facts, primary data. We have drawn the most obvious conclusion and have tested it intellectually from all angles and are satisfied with its veracity. It is very unlikely that our 3 OEM radiators were all bad in pretty much the exact same way and pretty much some time after the brass bleed screws were installed.

So, due to the plausibility of plastic deformation of the socket as it was not designed to holster something that expands the way brass does, and coupled with the consequences of sticking with the plastic screw (deterioration etc) to be highly remote, and since nobody give's a rats ass that the radiator looks pretty with brass, and since bleed socket failure means replacing the entire radiator or worse, the mafia hereby designates this as a Needless Risk.

Continue with it if you like.



rgds,
Roberto

Originally Posted by robertobaggio20

My apologies then. I'm got a friend in 3D with an E34. We often work on our cars together. One old and one new radiator referred to in my op came from his car and of course the other old radiator (which, come to think of it, was just over 4 years old which isn't all that old at all) was on mine.

Yes I agree that no one else seems to have had trouble with their brass bleeds screws. Be that as it may, it is my advice that the brass bleed screw be abandoned in favour of the stock plastic one. The stock plastic screw does not deteriorate the way the E39ers have experienced, it is simple to manage, you just need to be measured in your torque when you both unscrew it from the socket and when you tighten it back, that's about it. Our experiences are direct observations, facts, primary data. We have drawn the most obvious conclusion and have tested it intellectually from all angles and are satisfied with its veracity. It is very unlikely that our 3 OEM radiators were all bad in pretty much the exact same way and pretty much some time after the brass bleed screws were installed.

So, due to the plausibility of plastic deformation of the socket as it was not designed to holster something that expands the way brass does, and coupled with the consequences of sticking with the plastic screw (deterioration etc) to be highly remote, and since nobody give's a rats ass that the radiator looks pretty with brass, and since bleed socket failure means replacing the entire radiator or worse, the mafia hereby designates this as a Needless Risk.

Continue with it if you like.



rgds,
Roberto

So you want people to accept your hastily drawn conclusions, made by two kids, on their first cars over the folks on the e39 forum and several posters here, presumably because you call yourself mafia?

You accuse the e39 forum over overtightening their plastic screws, when it is pretty obvious, that is what you did with the brass ones.

Pure comedy

I feel like I need to weigh in here.

I have the brass bleed screw. I have had it for 50K+ miles with no problems and no leakage. When I installed it and bled my system, I snugged it down only to the point of stemming the flow of coolant (which was VERY LITTLE torque at all). I have not done any radiator flushes nor have I felt the need to. I have not loosened and re-tightened my bleed screw multiple times. I have had NO leaks.

I’m not an engineer, so I can’t speak to the expansion rates of brass vs. plastic. However, I seriously question whether the brass bleed screw expands at all at the temperatures it is subjected to. Even if it does, I can only imagine that it is only a couple of microns at best.

I think that one has to look at the hardness rating of the opposing materials in question. Plastic to plastic (i.e. plastic bleed screw to plastic radiator material) has the same hardness rating unless they use differing plastics, which I doubt. Brass is obviously harder than plastic.

My thought is that every time the bleed screw is removed and re-tightened, there is minute stress on the threads of the plastic bleed screw and on the threads of the radiator. Keep in mind that the plastic of each component becomes more brittle as they undergo numerous heat cycles. Done enough times, and perhaps with too much torque (remember, the bleed screw only needs to be snugged down to the point that coolant no longer flows), the threads of either the bleed screw or radiator become stressed to the point that they begin to fail and it requires more torque to get a seal. Do it enough times and BAM – you got a leak. By having a brass bleed screw, you at least take out the brittleness factor of one of the components.

As to the E39er’s having differing experiences with their plastic bleed screws than us E34er’s do ….. it is not due to parts or the series of the car. It is likely due to operator error. The part number for each bleed screw is the same. There are a couple of different manufactures of the bleed screw so there is a possibility of a variable there.

I think that ultimately it comes down to how often the bleed screw is manipulated, how old the components are and how much torque is applied to the bleed screw. Four year old, heat cycled plastic will become brittle to the point that the threads will fail if stressed too many times.

I will continue to use the brass bleed screw. I just don’t monkey with it unless necessary and have a very light hand when torqueing it down.

^ that.



the bit about the microns was my favorite.

"I dont have an Electron Microscope, so I can not be 100% accurate in the variation of size, weight, and density of the bleed screw, but, using deductive reasoning and logic, I find it to be a negligable amount."

Originally Posted by snowsled7

So you want people to accept your hastily drawn conclusions, made by two kids, on their first cars over the folks on the e39 forum and several posters here, presumably because you call yourself mafia?

You accuse the e39 forum over overtightening their plastic screws, when it is pretty obvious, that is what you did with the brass ones.

Pure comedy

Better 2 kids than an old fart frightened of gasoline and alcohol anyday.

And are we on the same forums or in the same dimension ? Where did I say that the E39ers overtightened their bleed screws? It is unlikely that they did. However, obviously they have experienced problems. I'm guessing that its because they came with a bad batch.....see doru's post in this thread. It happens in all manufacturing cycles. However, that is pure speculation, as is the notion that bleed screws that break must be due to operator error.

I take Steve's point about not 'monkeying around' with the bleed screw, but respectfully disagree that it ought to be treated as a fragile object. As long as you use light torque to screw in and screw out, the threads themselves would be unaffected....you can flush the radiator every day and it will be fine. I do not think that it deteriorates and becomes brittle in 3-4 years, if not lifetime warranty radiators sold by dealers (at 2-3 times the normal price of radiators of course) would have an exclusion clause on the bleed screw or strict instructions that they should only be professionally handled. Too much good plastic in and around the radiator for them to intentionally use a poor quality type for the bleed screw, and the radiator is not a china made consumer item that is meant to disintegrate within a few years (if at all) so the rules that apply are unlikely to translate to the radiator.

My friend has had his E34 for 10 years. Flushes the radiator every couple of months in fact he's the one who showed me how to do it first. Radiator has never been changed before, until several months after I gifted him with a brass bleed screw around 2 years back. We both thought it was operator error...seemed unlikely to be anything else. Then my rad went, and then we discovered his new rad's bleed socket was suddenly looser than it should be. The pieces fell together and we tossed out the brass screws.

Originally Posted by robertobaggio20

Better 2 kids than an old fart frightened of gasoline and alcohol anyday.

And are we on the same forums or in the same dimension ? Where did I say that the E39ers overtightened their bleed screws? It is unlikely that they did. However, obviously they have experienced problems. I'm guessing that its because they came with a bad batch.....see doru's post in this thread. It happens in all manufacturing cycles. However, that is pure speculation, as is the notion that bleed screws that break must be due to operator error.

I take Steve's point about not 'monkeying around' with the bleed screw, but respectfully disagree that it ought to be treated as a fragile object. As long as you use light torque to screw in and screw out, the threads themselves would be unaffected....you can flush the radiator every day and it will be fine. I do not think that it deteriorates and becomes brittle in 3-4 years, if not lifetime warranty radiators sold by dealers (at 2-3 times the normal price of radiators of course) would have an exclusion clause on the bleed screw or strict instructions that they should only be professionally handled. Too much good plastic in and around the radiator for them to intentionally use a poor quality type for the bleed screw, and the radiator is not a china made consumer item that is meant to disintegrate within a few years (if at all) so the rules that apply are unlikely to translate to the radiator.

My friend has had his E34 for 10 years. Flushes the radiator every couple of months in fact he's the one who showed me how to do it first. Radiator has never been changed before, until several months after I gifted him with a brass bleed screw around 2 years back. We both thought it was operator error...seemed unlikely to be anything else. Then my rad went, and then we discovered his new rad's bleed socket was suddenly looser than it should be. The pieces fell together and we tossed out the brass screws.

I remember why i added you to my ignore user list. im going to go ahead and re-add you to it. your the only one thats ever been on it across 3 forums I'm active on. Congratulations

but i will say you are wrong. if you have worked on an E46 or even an E36 before, you will know how incorrect you are about the plastic comments above

Originally Posted by robertobaggio20

My friend has had his E34 for 10 years. Flushes the radiator every couple of months in fact he's the one who showed me how to do it first. Radiator has never been changed before, until several months after I gifted him with a brass bleed screw around 2 years back. We both thought it was operator error...seemed unlikely to be anything else. Then my rad went, and then we discovered his new rad's bleed socket was suddenly looser than it should be. The pieces fell together and we tossed out the brass screws.

Proof than neither one of you has a clue. Flushing every two years is a smart practice, flushing every two month is just plain nonsense. It is a waste of time and materials and clearly leads to damage. The bleed screw was not designed to be fiddled with by kids every two months, THAT is what caused the failure. The obvious answer has been there all along, you kids need to own it, not give poor advice to others based on nonsense.

Originally Posted by _Ethrty-Andy_

I remember why i added you to my ignore user list. im going to go ahead and re-add you to it. your the only one thats ever been on it across 3 forums I'm active on. Congratulations

but i will say you are wrong. if you have worked on an E46 or even an E36 before, you will know how incorrect you are about the plastic comments above

Ok, so now someone who :

1. Without provocation, calls a kid who drove dangerously and killed two of his friends and is now stuck in jail for a few years, a wanker,

2. Created a post about forum etiquette that is now actually a sticky and has been so for nearly a year, has been on these forums for 4 years and has nearly 5k posts to his name and so is most certainly not a newbie and yet,

3. Posted a question about an important and vexing car problem that he had, received the correct answer within 24 hours, didn't bother to read the responses, waited 2 weeks, somehow found the same answer from someone else, tried it and it worked, came back and posted his results, realised that the answer was there all along, and didn't bother to even thank the numerous people who had replied to him, just like a happy go lucky kid.

4. Cannot concede positions that he has taken when he has been emphatically proven to be incorrect by actual workmen,

...has put me on HIS ignore list ??

Oh woe is me !!!!

Originally Posted by snowsled7

Proof than neither one of you has a clue. Flushing every two years is a smart practice, flushing every two month is just plain nonsense. It is a waste of time and materials and clearly leads to damage. The bleed screw was not designed to be fiddled with by kids every two months, THAT is what caused the failure. The obvious answer has been there all along, you kids need to own it, not give poor advice to others based on nonsense.

Snowy darling, I know you need to change the prescription on your glasses (may I suggest lasik surgery instead?) but I did not say we flush the car every 2 months. Of course, you are the guy who feels the engines and/or hgs will self destruct if they are merely allowed to run hot at 3/4, perhaps not making the distinction between a straight six and a renesis wankel engine.

You can only damage your radiator's bleed screw and its socket if you do not know what you're doing when you open and close it. As Steve said, use a light hand when opening and closing. And obviously, pay attention to the task to avoid unforced errors....the thing is made of plastic and not metal. Screw it in with your fingers first to ensure that it goes in straight without force, and then use a coin or a screwdriver for the final tightening.

I think its daft to think that bmw would create a bleed screw that would intentionally strip the threads of its socket. As mentioned, my friend who has been flushing his radiator for 8 years only experienced a cracked socket nearly a year after he started using the brass bleed screw. While I used to be more impulsive when it comes to my car, my friend is really very conservative and requires alot of urging to step away from the norm. And he tightens down the screw only to the point where coolant stops flowing out. The radiator in question was more than 10 years old and had been regularly flushed (hey, he can afford it) for 8 years before the incident concerned. So, I feel that any individual bias I may bring to the table has been largely discharged here. Of course snowy, you can say that I'm making this all up.

I've placed my primary evidence in front of everyone. Everyone else has placed their evidence here as well. Logic must be applied by the individual reader, who is ultimately the person who carries the risk. I do realise that my experience seems to be singular. The rest is history.



rgds,
Roberto

Bobby, when your experience is singular, you should probably consider conceeding the point. I do realize that is beyond your abilities and, you prefer to be wrong and defend it.