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

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)?

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?

Once the pin/clip is released if the hose does not easily come off you will need to gently twist it back and forth while pulling. You are just breaking the o-ring seal from the hose to the lip of the radiator hose, Do not rock it back and forth but just twist it a bit and pull.

Originally Posted by oembimmerparts

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.

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!

Originally Posted by bluebee

Well that's one way to clean your engine bay.

thank you now i don't have to pay some one to tell me to bend over (had a few pinhole leaks under bleed screw on hose that was hitting fan then belts and eating them away)

Blubee--may as well figure to replace the cooling system if you haven't as of yet--the plastic is trying to tell you something--it's gotten old my freind and will let you down if you try to trust it further.

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?

On our model cars the only avenue is the plastic stat housing--the early year engine's M52 have available the
alm stat housing

Originally Posted by poolman

On our model cars the only avenue is the plastic stat housing--the early year engine's M52 have available the
alm stat housing

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!

thank you the link is very helpful next time i will search more carefully with more keywords so others don't have to keep repeating themselves

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?

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

Originally Posted by energizedmortal

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!

Looks like Rexgo used this tool below to 'exploit the gap' in removing the hoses:
- Rexgo's '97 528 Cooling O'haul

Originally Posted by energizedmortal

... 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

Exactly! What the heck are these guys thinking? I have yet to see a failure related to brass bleeder screws. I ordered two for my car, not realizing at the time that the V-8 only had one bleed screw. So I gave the extra to 540Alex last weekend.

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.

Originally Posted by pleiades

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

Originally Posted by cali1995*joy

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.

I'd like to make a suggestion. When installing anything with O-rings, use a film of Magic Lube on the O-ring to prevent binding and to aid in future removal.

+1 I used sil-glyde on a few o-rings I worked on this weekend, and it was almost too lubed. Slipping free again, etc. Amazing what some lube will do.

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.

If the germans had figured out how to make good rubber and plastic they would have won the war !! These cars are old and everything you touch crumbles. I dropped the radiator fan six inches to concrete, and two blades snapped off.

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

Originally Posted by cwpo1

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.

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!). 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).