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Specific Question: How do you safely remove the upper radiator hose with u-pins?

60K views 30 replies 13 participants last post by  bluebee 
#1 ·
Car was running great after an alternator and belt-drive system repair but I figured I should go the extra mile and bleed any air in the cooling system because there was a slight leak at the nipple that I repaired.

I first followed the cn90 bleed method and then the conflictingly different nny528i bleed method ... and in the process, I twisted the bleed screw one too many times.

The bleed screw broke in half.
I tried to extract it (dumb mistake; I should have drilled it out); and that broke the bib around the bleed screw. No big deal, now I need a new hose.

BUT ... here's the situation:
- I'm really (really) tired of breaking things ... I really am. Almost anything PLASTIC has broken on me in this job ... so I'm going to ask a dumb question first ...
- In the morning, I will remove the upper radiator hose.

HERE IS THE DUMB QUESTION:
May I ask ... HOW do you remove that upper radiator hose WITHOUT breaking more things (specifically the thermostat housing and the radiator neck)?

 

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#2 · (Edited)
At this point, I've pulled the pin right off the radiator neck half of the upper radiator hose (at this point, everything plastic on this E39 is starting to feel like a grenade) ... I tugged ... I pulled ... I twisted ... but I'm scared!

But, I'm sooooooo (so very) tired of breaking plastic, that I don't want to remove this hose the wrong way!

What's the RIGHT way to remove the upper radiator hose WITHOUT breaking the neck of the radiator in the process?

 

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#4 · (Edited)
Do not rock it back and forth but just twist it a bit and pull.
Thanks for the help. I got the radiator hose off without further damage.

It only took about five minutes once I had the confidence of knowing what I was doing.

For others who have never done it before, I'll write up a quick pictorial DIY on how to remove the upper radiator hose and post it next.

 

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#5 ·
Here is a simple radiator hose removal DIY.

I believe it shows a novel method for removing the upper radiator hose and which I think eliminates any downward or twisting force on the brittle radiator neck and thermostat housing.

This method I came up with (out of necessity) applies axial forces only!










 

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#9 ·
good point poolman- the upper radiator hose warned me of the thermostat housing plastic so i replaced it too...but do know that i just replaced my radiator, cap, and reservoir a year ago (pressure test didn't show anything on that side) do you recommend aluminum thermostat housing, radiator and bleed screws?
 
#11 ·
Poolman's right (as usual) ... the later model E39's have the thermostat built into the housing and the only other option is Zionsville (I think) which is way too expensive for most of us.

The brass bleeders are recommended by most; but they are not required.

If you want a good list of recommended cooling-system replacement parts, spend time here. The whole point of making that list was for us to come up with the best recommendations so that your question is answered before you ever asked it.

BTW, Poolman ... do you know anything about pools? I just bought a house with a big pool and it's driving me crazy! So much to learn!
 
#13 ·
Today, another driver reported they broke the expensive plastic on the housing trying to extract a $3 broken bleeder screw.

The question we should answer for the NEXT person is how best to remove the broken bleeder screw so that the fragile plastic housing around it doesn't crack.

I suspect the better way, once a bleeder screw breaks, is to remove the entire hose and drill it out with successively larger drill bits.

Do you have a BETTER idea for safely removing the broken half of a plastic bleeder screw?

 
#14 · (Edited)
when my bleeder screw popped in half i used a lighter to warm up the tip of a screw driver and it melted right into the broken bleed screw, i let it dry for a couple of seconds and just unscrewed it ...for removing the hose without breaking anything i used your method of exploiting a gap until i just used my hands to gently twist it in and outward not down or up to create any pressure on the parts it connects to. i have installed the metal bleed screws from autohasaz even though a tech at bmw said metal bleed screws were not designed for those plastic parts and it wasn't a good idea, like plastic bleed screws that pop in half (murphy law) are a good idea
 
#15 ·
it melted right into the broken bleed screw
I'm going to have to try that on my broken bleed screw and hose and report back how it works (although mine is all botched up at this point).

i used your method of exploiting a gap
I like that terminology! I'm glad it worked for you!
 
#18 ·
I plan to get a couple of the brass screws myself.... Only thing I'd caution, be aware that with a brass screw, the weakest threads will now be in the hose or expansion tank, and replacing those (if they strip) is a lot more expensive and time-consuming. Don't overtighten.
 
#19 ·
be aware that with a brass screw ... Don't overtighten.
Regarding brass screws, today this thread expounded upon them nicely, along with warnings such as the sentiment quoted above:
- E39 (1997 - 2003) > The UNOFFICIAL Brass Bleeder Screw Thread

In addition, today the following thread was opened up which was redirected here:
- E39 (1997 - 2003) > 1999 BMW 528i E39 Radiator hoses

I am trying to replace the radiator shrould. I need to remove some of the hoses to have better access. Does anybody know how these hoses can be disconnected from the radiator and radiator expansion tank ? I did remove clips securing the hoses but I am not sure whether I should twist and pull.
 
#22 ·
For the cross-linked record, we discuss the removal of the hoses using only axial forces (Fa) in this thread today:
- E46 (1999 - 2006) > Testimonial: Coolant system overhaul



Other useful innovative solutions were also discussed:
- Tricks to replace the M54 fan clutch nut (1)
- Innovative solution to the M54 lower-hose thermoswitch o-ring (1)
- How to non-destructively remove the brittle plastic radiator nipple (1)
- How to non-destructively remove the brittle expansion tank nipple (1) (2)
- How to properly remove the original OEM BMW Oetiker clamp (1)
- How to not misplace the thermostat wiring loom (1)
- How to properly replace a broken bleeder screw (1)
etc.
All of these were based, at least in part, by mistakes:
- How not to remove the nipple from the E39 radiator (broken radiator nipple)
- How not to put your E39 fan clutch back on (crooked fan clutch nut)
- How not to bleed your E39 cooling system (1) (broken bleeder screw)
- How not to replace your E39 thermostat (thermostat loom misplaced)
- How not to remove your E39 expansion tank (broken expansion tank nipple & cn90 repair)
- etc.
 

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#24 ·
For the cross-linked record, here's another way to remove the large radiator hoses:
- E39 (1997 - 2003) > Notes from my cooling system overhaul

The top and bottom hoses were about 40.00 together from auto parts warehouse dot com. Pull the clip up with a pair of needle noses and pull loose. Putting them on I had to grease the radiator and hose coupling to get the new ones on. Same thing with the sensor in the lower radiator hose. I had grease the hole as well as the sensor, wrap with towel (so I would not break it) and squeeze it in. I did this part at the kitchen table. I could not imagine it going in while attached to the radiator.
 
#25 ·
Upper radiator hose clamps?

Auto part Fuel line Pipe Automotive fuel system Engine
Hi, newbie here! First let me apologize if this has been answered before, I can honestly tell you I really searched for a LONG time trying to resolve this myself. We recently purchased a used 2003 BMW 530i and are very happy with it. However we now have a leak in the upper radiator hose and I am aware from reading the forum that the whole coolant system should be replaced but we just can't do it at this time. I have found Bluebee's instructions on removing the hose to be extremely helpful and have tried it myself but it's just not budging! I feel like the screw driver is causing too much damaging with each twist (and if I cause any more expenses my hubby will never let me hear the end of it!:tsk:). My question is...can the middle hose be removed, leaving the "quick connects" (with the pins) still attached to the car and if so do I cut the metal rings off? I've noticed the auto shops tend to just carry the hose itself anyway. Also is there a step by step instruction for just the hose removal? It seems to be a simple process, I'm just scared because of all the new terms I'm learning such as "bleeding", etc... HELP! (Pretty please).
 
#26 ·
You could cut the ring off with a hacksaw. If you gently rock the hose end at the radiator while pulling it straight back it should loosen up, eventually! Once it seems to get loose try to twist it back and forth while you are pulling and rocking it.
I had to pull on mine so hard I thought the end was going to break off the radiator, but it didn't.
If you are concerned about your hubby giving you grief if it breaks have him do it!
 
#27 ·
Thanks Jim! Your solution sounds like it could work, I'll let you know what we end up doing. As far as the hubby also great answer, love it (unfortunately he's as mechanically inclined as I am)! I grew up with a dad who did all our car repairs so it just kills me to pay a mechanic. I guess I should look at it in a positive way, I'm helping our economy =/
 
#29 ·
Then both you and the hubby should do it together.
My dad was a Navy aircraft mechanic which is where I learned to wrench on cars. I hate paying for anything I can do myself too.
 
#28 ·
Bee...........Hi! Old thread. Sure by now you have discovered brass. You removed that metal U-clip right. Actually you can bend the crap out of it although you will never need to and reform it. It performs easiest of tasks. Anything to hold hose. Exactly like injector clips...just on steroids.
 
#30 ·
Sure by now you have discovered brass.
Yup:
- How to retrofit cooling system brass bleeder screws (1) (2)

As an update, here is a quote from another thread today regarding this method and its pitfalls:

I want to add that Bluebee's posts were incredibly helpful in this process, in particular the little-by-little prying of the hose connector off the fittings. I worked IMMEDIATELY on the disconnection of the lower radiator hose fitting from the metal thermostat housing. I was hoping for the same with the lower connection, but in my 2001 540i6, there wasn't a lot of room to pry with the screwdriver, and there is no metal "ear" to pry against with twisting motion. Plus it is incredibly hard to see down there, even on a sunny day--I recommend additional electric lighting, because even if you do manage to develop a crack to insert a screwdriver into, you won't be able to see it down there. It's just very awkward.

When you apply twisting/prying motion on the lower fitting, you're twisting/prying against the plastic radiator fitting, so you have to use some caution and patience. I found that my hose was on so bleeding tight that I didn't seem to be making much progress: every time I'd exploit a gap down there, and reach for the next biggest screwdriver, the gap would close itself. And then the twisting/prying motion was starting to do damage to the plastic I was prying against. But still nothing would give. And there aren't many angles from which you can twist/pry on the lower hose fitting, due to stuff being in the way. Most of the twisting/prying is going to be from the top, none from the bottom, very difficult from the right side (as you are facing it) and non-existent from the left side. So you lose the potential advantage of being able to pry a little all around the fitting, which would doubtless help if it were possible. If you could get underneath the car, and pry from both the top and bottom, that would probably get the job done faster because of the way the hose fitting is "keyed" into the radiator fitting. But it was cold and damp (and actually snowing) when I did this in my office parking lot and my car is lowered, so it would not have been easy for me to get underneath it.

Things started moving in the right direction for the first time when I pried apart a little, soaked it with PB Blaster, and tapped it with a machinists hammer lightly all around the hose fitting. After a couple of iterations, and continuing both the twisting/prying screwdriver technique outlined by Bluebee, and rocking back and forth a little using a screwdriver stuck down in the hole made available by removing the temp sensor (BTW, if you do this part, you are NOT going to be able to reuse the existing hose), it gradually began to give way.

None of this would have been possible without Bluebee's great instructions and tips, and removal of the fan shroud before attempting the lower hose disconnection.

One last thing: after getting the doggone lower radiator hose off, I STILL could not tell where the water was leaking from it after examining it. I was afraid that would happen, which is why I also bought a new expansion tank just in case (my existing one was 12 years old). I'm not very knowledgeable about radiator hoses but I would bet that if you put 2 bars of pressure and 110 degree celsius coolant into it you'd be able to see some sort of defect open up. But maybe without that pressure it just won't be evident by normal examination. I've made a mental note to myself in the future just to replace suspect hoses, and not fret about being able to pinpoint a leak exactly each time. Once you go to the trouble of taking the thing off, just replace it with a new one, IMHO.
 
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