1995 BMW 525i Coolant and Hose issues. What are these hoses?

[codebroker]

Hi. I have a 1995 525i. The other day I noticed some gas coming out under my hood while I was driving. I pulled it over and the upper radiator hose fell off. I put it back on and got it to a parking lot right as the engine started overheating. I checked the coolant level and it was completely empty, so I thought the hose broke and it needed coolant.

The next day I replaced the upper hose and added coolant. I tried to get it home, but it overheated again, and I noticed two hoses near the engine/thermostat housing (I'm not exactly sure, as I'm not too familiar with the inner workings of cars) that were cracked/broken. They come out of the engine near the front and go down under it to the side. I can't find anything about these hoses in the service manual since I just don't know what they are. Some kind of gas, I'm not really sure what, is coming out of one or both of them when I run the car. I then got the car towed.

The next day, I went out to check on the coolant, and it was all gone. There was no coolant under the car. I found out that I probably needed to bleed the cooling system to fill it properly. I just did that this morning (although I'm not sure if I did it completely correctly), and when I came back the expansion tank had fallen below halfway full. I do NOT think it's a head gasket leak, as the coolant in the expansion tank is not bubbling when I run the car.

My questions are these, and I'll attach some pictures to help:
1. Is the bleed screw next to the expansion tank the only one I need to loosen to bleed the system?
2. Is the expansion tank where I should be adding coolant?
3. What are the hoses by the engine? What gas could be coming out of them?
4. Could this also be a thermostat issue? Where is the thermostat housing on this car?

Here's a link to the images:https://imgur.com/a/M8Iu65V
The first one is the cracked hoses themselves. you can barely see the 2nd one under the top one.
The second one is the upper hose. In the top right you can see where those hoses are.

Thank you

[shadowpuck]

my first question is when you say you saw gas coming out from under the hood - what do you mean? actual gas, as in fuel/petrol? or a vapor?

the hoses in your first pic are for crankcase ventilation and do not have anything to do with the cooling system. you do want to replace them and have that system working but, at the moment, it's not as critical as resolving the other issues.

what process did you use for bleeding the system?

the second pic is your upper radiator hose - it connects to your thermostat housing which is cracked (and looks like original plastic - amazing!). the housing should be upgraded to a metal housing.
the entire cooling system is most likely due for replacement - this means all hoses, coolant, water pump, thermostat, expansion tank, and radiator.

your questions:
1. yes, on this car
2. yes
3. CCV system - see notes above.
4. your housing is leaking/cracked, that's certainly an issue. see note above for location.

check out realoem.com - enter the last 7 of your vehicle's VIN and then start looking at the parts catalog. it will have some illustrations of parts locations which will help.

you mentioned a service manual - which one are you using?

[codebroker]

I don't actually know what gas was coming out. It was coming from the detached upper hose, but I don't know what it was.

To bleed the system I loosened the screw until the level dropped and coolant came out. Then I started the car, tightened the screw, and filled the tank up. Is this right?

My service manual is the BMW 5 series service manual for 1989-1995. ISBN is 0837603196.

[shadowpuck]

ok, so, looking up the ISBN - it's the bentley service manual. at least that's a good service manual.

i still don't understand what you mean by gas - do you mean steam? was it liquid or did it smell like fuel?
remember, we aren't standing next to you by the car so descriptions will help.

mostly, i'm trying to determine if you have a fuel leak as that's a serious issue. while i wouldn't expect fuel in the area you are describing, it's close enough to want to be specific.
i'm guessing you are talking about steam coming out of the upper radiator hose.

and, no, that's not bleeding the system - or, at least not all the way.

there's some good procedures here:
https://www.bimmerforums.com/forum/s...Procedures-FAQ

regardless, until the cooling system is replaced it's not going to matter much.

[codebroker]

It didn't smell like fuel, but it did smell. It was liquid.

I bled the system how that link described. A lot more air came out, so thanks for showing me that. The coolant level hasn't dropped at all from when I bled it properly yesterday until now.

Just found a thermostat assembly, so I'm gonna start with that and the crankcase ventilation hoses and see how it goes. Do you know what the hoses might be called on part sites? I see the crankcase breather hose, but no other hose related to crankcase ventilation.

[shadowpuck]

check out realoem.com - enter the last 7 of your vehicle's VIN and then start looking at the parts catalog. it will have some illustrations of parts locations which will help.

see above.

[codebroker]

Yeah I checked there and on some other parts sites. Still not 100% sure. Are they the hoses listed here? https://www.realoem.com/bmw/enUS/sho...diagId=11_4857

[shadowpuck]

yup, that should be it. i'd get the o-ring too, and that connector at the bottom of the hose might be handy to have on hand.
the car is old, the plastic is brittle so it can break easily - especially judging by the condition of that hose.

i think fcp euro had a kit for this job - i'd check their site for sure for your parts.

i don't know what your plans are for this car or your situation, but, again, if you haven't replaced the cooling system in the last 60-80k miles it's due as well.

one last comment on the e34 - if yours does not have rusty doors (especially the door bottoms) be sure to take care of this thing - non-rusty e34s are almost unheard of anymore.

[shadowpuck]

one more suggestion - you can take the part numbers from realoem and see pictures (if the camera icon isn't listed in realoem) by searching the internet. works great to sometimes confirm what you see in the catalog is what you are trying to order.

[codebroker]

Thanks a bunch for the info. I'm gonna consider replacing the whole cooling system, but that's beyond a DIY job for me probably.

[moroza]

The gas (referring to the gaseous phase of matter, contrasted with liquid or solid) coming out of that severely cracked big hose is crankcase fumes. There should not be gas(oline) in it. It does need to be replaced, but is not your main problem. The third hose in the photo, tucked way underneath to the right of the other two, is indeed the fuel supply line.

A headgasket can fail without producing bubbles in the coolant.

E34 M50 cooling system hoses:
aux pump to heatervalve 64211384763
engine to aux pump 64211384746
Canadian cars apparently ran no aux pump, used hose 64211391387 from engine to heatervalve. I have no idea why this is a separate part. 746 just as easily goes straight to the heatercore as to the aux pump. The aux pump helps heater performance at the cost of reliability (brittle old plastic). I don't use one and find my heater adequate.
heatervalve to heatercore, port 64211384711
heatervalve to heatercore, starboard 64211384712
upper radiator 11531720678
lower radiator 11531722852
four-way between radiator, block, throttlebody, and heatercore return, known as the "octopus hose" 11531738054 Gates 24131 Vaico V20-0155
block to throttlebody thermostat 13541738622
throttlebody thermostat to throttlebody 13541730684

+1 to the suggestion to overhaul the entire cooling system, including a metal thermostat housing, correct thermostat (88C or 92C), metal radiator (use CSF, not Mishimoto; see the last page in that thread), all hoses, BMW blue coolant with distilled water, waterpump with metal impeller... and I recommend also deleting the auxiliary pump. Heater core is a matter of opinion; it's plastic and contains coolant, but catastrophic failure is rare. Heater valve is also a matter of opinion; it's also plastic and contains coolant, but catastrophic failure is known to occur. The problem with that one is there are no good options for replacement - used are all old, new genuine BMW are hideously overpriced, and aftermarket appear to all be from China.