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E34 (1989 - 1995)

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  #1  
Old 10-31-2012, 08:34 PM
robertobaggio20 robertobaggio20 is offline
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Useful fix if you have bleed screw problems

Hi Everyone,

I recently had a problem with my old radiator. The bleed screw would not screw itself in nicely. It kept turning and turning and would not tighten and stop. Now please bear in mind that the bleed screw can be tightened ad infinitum with increasing force, but that should not be done at all. As long as it reaches a point where it feels normally tight, you can stop there. That's usually where I stopped, but this time it kept turning and turning.

Upon close inspection, it became clear that the thread in the bleed socket had faded out. There were no cracks.

This is how I solved the problem :

1. I wound pvc tape ('pipe tape ') around the bleed screw several times and screwed it in.

2. It still kept turning and turning without tightening.

3. I then wound even more pvc tape. This time, it was too much and I could not screw it in properly.

4. So, I used an intermediate length of tape intermediate between the two steps earlier. It still kept on turning in the socket, but I decided to leave it. Ran the engine at idle for 15 minutes. No problems, no leaks, escaping coolant, or steam (you must check for steam). Drove the car off. 25 minutes later, reached home and double checked. No leaks or steam.

5. Subseqently, I removed the old pvc tape, used some new one, and then applied a large dollop of white high temp silicone window sealant. Then I screwed this in. Again, unfortunately, the bleed screw kept turning and turning, but I stopped it as I pressed it down and it seem to reach near the correct height it should be.

6. A large amount of the sealant had splayed out of the socket during the tightening process. This is normal.

7. Left it for 30 minutes to set. Then drove off. Checked for steam at the socket on several occasions after that. No problems. Drove the car damn hard as well, and checked. No problems.

While using both of the methods above, the engine's temperature was perfectly normal.

The more permanent fix for this problem is to use a rethreading die to cut a fresh thread into the bleed socket, then wind the white pipe tap around the bleed screw, and then finally screw it in decently. This will avoid the need to repeat the sealant procedure each time you remove the bleed screw to bleed the radiator.

These procedures were actually more successful than I expected, considering that in both occasions, the bleed screw could be kept turning on and on. Was quite concerned that it wouldn't last under pressure. No problems whatsoever. God did not have to be great this time, the sealant and pipe tape sufficed.



rgds,
Roberto

p.s. White pipe tape can be wound around to form an O ring effectively for anything. I wound a little bit extra near the top of the bleed screw where the existing O ring was, before winding it around the thread itself, in both of the procedures listed above.
p.p.s. If you ever need to do this, let the engine reach operating temperature and check to see that there are no leaks and no steam (hold your hands or a place a cup over the bleed screw, or shine an led flashlight close to the area) before you drive off. Check this every day for 3-4 days right after you've finished driving for the day, while keeping the engine running at idle. If there are no problems and no hints of a problem, then its a solid fix.
p.p.p.s. Retreading is the only long term fuss free solution.
p.p.p.p.s. Changing the radiator is the only worry-free solution. You may ultimately elect to do this - radiators are fairly cheap these days and if you know how to remove your clutch fan, its not hard to change the radiator at all and kinda fun (remember to tie up the transmission cooling lines to prevent excess oil spillage, and remember to use carb cleaner and simple green to clean the ac condensor that becomes exposed when the old radiator is removed). However, with this fix, you do not need to have your show stopped right on the spot, and you'll have time to decide your schedules and workshops etc. If you don't change the radiator, no problem. Whenever you bleed the radiator (flush the coolant once a year) then you'll just have to reapply the high temp clear/white silicone window sealant again. Removing the bleed screw ruptures the old sealant.
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  #2  
Old 11-01-2012, 05:34 AM
snowsled7 snowsled7 is offline
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Quote:
Originally Posted by robertobaggio20 View Post
The more permanent fix for this problem is to use a rethreading die to cut a fresh thread into the bleed socket, then wind the white pipe tap around the bleed screw, and then finally screw it in decently. This will avoid the need to repeat the sealant procedure each time you remove the bleed screw to bleed the radiator.
Re-threading is the proper fix, if possible. If the threads are completely stripped, you were also correct about using a replacement radiator as the best solution.

Quote:
These procedures were actually more successful than I expected, considering that in both occasions, the bleed screw could be kept turning on and on. Was quite concerned that it wouldn't last under pressure. No problems whatsoever. God did not have to be great this time, the sealant and pipe tape sufficed.
Report back next year when you do your annual coolant flush. I seriously doubt your repair is going to last this long, and I would advise against trying this as anything more than a quick, very temporary fix. It is certain to fail.

Thanks for the story bobby, please keep us updated on the status of the fix. I will be curious to see how long it lasts.

In the meantime, while you are doing experiments on your car, please do us all a favor and refrain from posting results until you have some real, long term experience with it. This procedure could easily result in a sudden, catostrophic coolant loss.
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  #3  
Old 11-01-2012, 06:26 AM
robertobaggio20 robertobaggio20 is offline
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This fix was suggested to me by a buddy who had used it before on his rad. The looseness of the bleed screw was worse on mine than his, yet it held up to very spirited driving which is why i said i was surprised. No coolant loss and no steam observed out of the bleed screw. It handled as much pressure as the rad cap. In any case i have changed the rad...with the clutch fan out, it was just too tempting not to try.

People can be as terrified of observed data as some. Its a free country.
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  #4  
Old 11-01-2012, 07:01 AM
robertobaggio20 robertobaggio20 is offline
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And of course the reason why the bleed screw fix held was because the silicone window sealant applied thickly all around the bleed screw before insertion, expanded as it hardened, holding the bleed screw fast against the walls of its socket, and OBSERVABLY able to handle the high pressures building up on a premium luxury sports sedan driven hard over three days, without a trace of a leak or steam.

There we are. Makes sense doesn't it? Except perhaps to superstitious lobbyists..who shall be left to their own imagined terrors henceforth....
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  #5  
Old 11-01-2012, 09:46 AM
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  #6  
Old 11-02-2012, 04:51 AM
snowsled7 snowsled7 is offline
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Quote:
Originally Posted by robertobaggio20 View Post
And of course the reason why the bleed screw fix held was because the silicone window sealant applied thickly all around the bleed screw before insertion, expanded as it hardened, holding the bleed screw fast against the walls of its socket, and OBSERVABLY able to handle the high pressures building up on a premium luxury sports sedan driven hard over three days, without a trace of a leak or steam.

There we are. Makes sense doesn't it? Except perhaps to superstitious lobbyists..who shall be left to their own imagined terrors henceforth....


Like I said, please spare us your miraculous results until you have a bit more than three days testing on it. You are probably the only person reading this that thinks a three day test makes for a solid conclusion.

Silicone shouldn't harden, and it certainly isn't designed to expand as you claim.

Just one more example of rigging your vehicle to blow, bobby baghead style.

Imagine your terror when it does let go, because it will....
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  #7  
Old 11-02-2012, 06:12 AM
robertobaggio20 robertobaggio20 is offline
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Quote:
Originally Posted by snowsled7 View Post
Like I said, please spare us your miraculous results until you have a bit more than three days testing on it. You are probably the only person reading this that thinks a three day test makes for a solid conclusion.

Silicone shouldn't harden, and it certainly isn't designed to expand as you claim.

Just one more example of rigging your vehicle to blow, bobby baghead style.

Imagine your terror when it does let go, because it will....

Perhaps you should read up more about the properties of silicone window sealant. lmgtfy.com ?

Oh sorry. Forgot it was you. My bad.

" Hosanna ! "

Last edited by robertobaggio20; 11-02-2012 at 06:15 AM.
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  #8  
Old 11-02-2012, 01:51 PM
txrealtor txrealtor is offline
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I'm not sure why anyone would do this "rigged up mess of a job" to their car.
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  #9  
Old 11-02-2012, 05:32 PM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by txrealtor View Post
I'm not sure why anyone would do this "rigged up mess of a job" to their car.
Its a quick fix that held up surprisingly well, (which I did not expect).

If fixes that are :

1. reliable, fast and can be implemented at any time of the day or night by yourself without anyone's assistance,
2, allows you to keep on driving after a tolerably short delay,
3. don't involve you carrying pounds of bulky material in your trunk in case you need to make that quick fix suddenly (one tube of high temp silicone window sealant and one roll of pvc tape, both of which are useful for more things than just bleed sockets that whose threads have gotten stripped due to repeated use over the years),
4. that save you time and money and helps you get moving without too much of a fuss, allows you to drive and schedule repair work at your convenience with yourself or your mechanic that might involve many other related components thus saving you alot of time and also money due to grouping work together,
5. which saves the lives of people who would otherwise be run over slowly by 3500 pounds of the panzergruppe's finest if they dare give you dirty looks that imply that you're driving an E34 because you're poor and can't afford "a decent car",
6. if you don't have a stop nag button on your spouse,

.....are not important to you, and if you feel these reasons wouldn't be relevant to others as well, then I understand why you feel the way you do.



rgds,
Roberto

Last edited by robertobaggio20; 11-02-2012 at 06:33 PM.
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  #10  
Old 11-03-2012, 05:11 AM
snowsled7 snowsled7 is offline
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The best fix for this is to not overtighten and strip out your bleeder

Glad to see the acknowledgement that this is only a quick and temporary fix.

There may be hope for you yet bobby.
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  #11  
Old 11-03-2012, 05:38 AM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by snowsled7 View Post
The best fix for this is to not overtighten and strip out your bleeder

Glad to see the acknowledgement that this is only a quick and temporary fix.

There may be hope for you yet bobby.

I did not overtighten, and yet it got stripped. Perhaps it had something to do with the fact that I was using a brass bleed screw instead of the normal plastic one, it may have expanded too much into the hard plastic socket. I'm not sure. Old radiator.

And I did not say that this is not a long term fix. Read my posts carefully. That being said, it probably is a long term fix. I said that I was surprised at how well it stood up to the pressure of hard driving. Remember, this was well within the ideal 24-hr recommended curing period of the thing, as stated on the back of the cover. And I just went to pick up another tube. Guess what ? They have pictures of radiators there on some of them....rtv sealants all. So i'm now convinced that this would have indeed held for the long term. Whenever I checked after the car had been driven, the sealant was rubbery hard, had not melted in the least, did not move, nothing whatsoever. And it was with the brass bleed screw. And it is good until 600 degrees F.

Of course, there's an ugly patch of dried sealant around the bleed screw that you'll need to contend with. Some black high temp spray paint dabbed on with a tiny paintbrush would take care of that. And there's the inconvenience of having to reapply this each time you flush the radiator. It will work for some folks, and they wouldn't have to first say Hosanna. As mentioned, I was surprised by how solid the fix was. Not a wisp of a wisp of steam. I checked with an upturned cup each time.

Snowsled, there could be some hope for you as well. This post was approaching politeness. I think the Hosanna's are working.

Have a good day my friend.


rgds,
Roberto
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  #12  
Old 11-03-2012, 05:58 AM
snowsled7 snowsled7 is offline
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Quote:
Originally Posted by robertobaggio20 View Post
p.p.s. If you ever need to do this, let the engine reach operating temperature and check to see that there are no leaks and no steam (hold your hands or a place a cup over the bleed screw, or shine an led flashlight close to the area) before you drive off. Check this every day for 3-4 days right after you've finished driving for the day, while keeping the engine running at idle. If there are no problems and no hints of a problem, then its a solid fix.

If you don't change the radiator, no problem. Whenever you bleed the radiator (flush the coolant once a year) then you'll just have to reapply the high temp clear/white silicone window sealant again. Removing the bleed screw ruptures the old sealant.
I do read your posts bobby, maybe you should? These quotes from your OP sure seem to imply that this could be a permanent fix. I didn't make that up, you said it. Just wanted to striaghten that out sonny.

I am quite sure that the only person entertained by your "hossanna" fest is you bobby. I personally am concerned for you..... yeah right.
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  #13  
Old 11-03-2012, 06:42 AM
robertobaggio20 robertobaggio20 is offline
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Originally Posted by snowsled7 View Post
I do read your posts bobby, maybe you should? These quotes from your OP sure seem to imply that this could be a permanent fix. I didn't make that up, you said it. Just wanted to striaghten that out sonny.

.
Yes, and that's what I mean. I never said that its merely a temporary fix. And now i believe its truly a permanent fix.

Of course, radiators being as cheap as they are, most people would eventually elect to replace theirs, as I did. The car is worth investing in. But its nice to be able to get good sound sleep at night until then. On my ride, this was as permanent a fix as can be. I drove the car hard (on the second day after the sealant fix). The radiator must have been under immense pressure. Zero problems, zero steam, rock solid. Take it for what its worth.


rgds,
Roberto
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Old 11-04-2012, 07:39 AM
snowsled7 snowsled7 is offline
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Originally Posted by robertobaggio20 View Post
Yes, and that's what I mean. I never said that its merely a temporary fix. And now i believe its truly a permanent fix.

rgds,
Roberto

Of course, seeing as how you only tested it for three days... I can see it isn't really worth anything. How do you honestly justify make such a statement? For entertainments sake?

I am glad to see you standing behind your research bobby, it definately helps illustrate your poor judgement in these matters.
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Old 11-04-2012, 10:15 PM
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