How many coolant hoses to replace? Should I replace them?

NYZ4Jack · 07-09-2012, 09:34 PM

Looking to do some preventive maintenance on the Zed. Model is a '05 3.0 M54 engine.

Will be replacing fluid, expansion tank, waterpump, thermostat & housing. I'm leaving the radiatior as it looks pretty good for 78k miles and I have a limited budget. Should I do the hoses? I hear there's an upper and a lower but on REALOEM, I see a total of 3 water hoses. How many and which ones should I replace? (The hoses feel fine. Firm, not dried out, etc. and no leaks anywhere)

seank · 07-09-2012, 10:14 PM

If they are fine, I would leave them alone. If you need to replace 1, I would replace all with silicon and you'll never have to worry about them EVER again.

Shipkiller · 07-10-2012, 06:56 AM

The hoses don't really go bad, it's the O-ring in each end of the hoses that starts leaking.

NYZ4Jack · 07-10-2012, 11:39 AM

Thanks for the tip Shipkiller. Are the O rings in the hoses replaceable? Do they sell them alone?

Thanks!

Quote:

Originally Posted by Shipkiller

The hoses don't really go bad, it's the O-ring in each end of the hoses that starts leaking.

Shipkiller · 07-10-2012, 02:38 PM

Yes, the O-rings are replaceable, but NO they (BMW) do not sell them alone. You have to size them yourself. Remember, they are METRIC O-Rings.

The piece (O-ring) that normally fails first and starts leaking is the temp sensor.

The first sign of a failing O-ring is you start to loose coolant but there is NO coolant on the under tray...

What happens is an O-ring is starting to become non-elastic and HOT coolant is weeping past and flashing into steam...

You can pull a hose off in about 2 minutes. They use positive locking wire spring retainers. Just pull the retainer up and pull the hose off. Cold of course.

Also make sure you do a very good visual inspection to the tank. Tanks are a known failure item on the M54 motors.

NYZ4Jack · 07-10-2012, 04:03 PM

YOU are the MAN!!! Just saved me a bunch of time and money. Thanks for the tip!
I'm going to change the expansion tank with a new one as a precaution.
I can pick up the O-rings from Home Depot or Autozone. Material of O-ring matter?

BruceJ · 07-15-2012, 03:15 PM

Quote:

Originally Posted by NYZ4Jack

YOU are the MAN!!! Just saved me a bunch of time and money. Thanks for the tip!
I'm going to change the expansion tank with a new one as a precaution.
I can pick up the O-rings from Home Depot or Autozone. Material of O-ring matter?

Material matters - http://www.marcorubber.com/compatibility.htm
Scroll down to Proplyene Glycol, although most materials are compatible with it.

Also look at the application: Heat range, Vibration, Pressure, Vacuum etc
http://www.marcorubber.com/material_chart.htm

Someone else may have a line on sizes - If not and it was me, I would get a nice set of calipers and measure.
http://www.amazon.com/dp/B001C0ZPNO/..._df_B001C0ZPNO You can find good quality cheaper than this.

Measure what?
O-rings are spec'ed for size by interior diameter and thickness(cross section).
1. ID: So if you can measure the diameter of the what the hose will attach to that will get you close. You still need to determine the cross section.
2. Cross Section: If there is a groove that the oring fits in within the hose and you can measure that - you may have your answer but it may need to be smaller here because its going to compress.
3. you should also measure the O-ring directly, to see how this corresponds to previous measurements . Cross section wise this is probably the better of the two

Just cause I'm so anal then I'd probably buy that size and one size up and down.
Glad I saw this - I replaced all hoses on my 3, but probably not with the z.

NYZ4Jack · 07-16-2012, 01:36 PM

wow! that's a wealth of information, even a bit overwhelming! lol
thanks, i'll definitely look into it!

Quote:

Originally Posted by BruceJ

Material matters - http://www.marcorubber.com/compatibility.htm
Scroll down to Proplyene Glycol, although most materials are compatible with it.

Also look at the application: Heat range, Vibration, Pressure, Vacuum etc
http://www.marcorubber.com/material_chart.htm

Someone else may have a line on sizes - If not and it was me, I would get a nice set of calipers and measure.
http://www.amazon.com/dp/B001C0ZPNO/..._df_B001C0ZPNO You can find good quality cheaper than this.

Measure what?
O-rings are spec'ed for size by interior diameter and thickness(cross section).
1. ID: So if you can measure the diameter of the what the hose will attach to that will get you close. You still need to determine the cross section.
2. Cross Section: If there is a groove that the oring fits in within the hose and you can measure that - you may have your answer but it may need to be smaller here because its going to compress.
3. you should also measure the O-ring directly, to see how this corresponds to previous measurements . Cross section wise this is probably the better of the two

Just cause I'm so anal then I'd probably buy that size and one size up and down.
Glad I saw this - I replaced all hoses on my 3, but probably not with the z.

07-09-2012, 09:34 PM	#1
NYZ4Jack Private 20 Rep 94 Posts Drives: 2005 Z4 3.0i Join Date: Nov 2011 Location: New York, NY iTrader: (0)	How many coolant hoses to replace? Should I replace them? Looking to do some preventive maintenance on the Zed. Model is a '05 3.0 M54 engine. Will be replacing fluid, expansion tank, waterpump, thermostat & housing. I'm leaving the radiatior as it looks pretty good for 78k miles and I have a limited budget. Should I do the hoses? I hear there's an upper and a lower but on REALOEM, I see a total of 3 water hoses. How many and which ones should I replace? (The hoses feel fine. Firm, not dried out, etc. and no leaks anywhere)
	Appreciate 0 Tweet Quote

07-09-2012, 10:14 PM	#2
seank enthusiast 48 Rep 1,695 Posts Drives: e30 m3,e90 wagon,sprinter,z4m Join Date: Dec 2011 Location: sacramento, ca iTrader: (4)	If they are fine, I would leave them alone. If you need to replace 1, I would replace all with silicon and you'll never have to worry about them EVER again.
	Appreciate 0 Quote

07-10-2012, 06:56 AM	#3
Shipkiller Colonel 188 Rep 2,138 Posts Drives: Me Join Date: Oct 2007 Location: Virginia Beach iTrader: (3) Garage List 2008 BMW Z4M Coupe [8.50] 2003 BMW Z4 Roadster [8.33]	The hoses don't really go bad, it's the O-ring in each end of the hoses that starts leaking.
	Appreciate 0 Quote

07-10-2012, 02:38 PM	#5
Shipkiller Colonel 188 Rep 2,138 Posts Drives: Me Join Date: Oct 2007 Location: Virginia Beach iTrader: (3) Garage List 2008 BMW Z4M Coupe [8.50] 2003 BMW Z4 Roadster [8.33]	Yes, the O-rings are replaceable, but NO they (BMW) do not sell them alone. You have to size them yourself. Remember, they are METRIC O-Rings. The piece (O-ring) that normally fails first and starts leaking is the temp sensor. The first sign of a failing O-ring is you start to loose coolant but there is NO coolant on the under tray... What happens is an O-ring is starting to become non-elastic and HOT coolant is weeping past and flashing into steam... You can pull a hose off in about 2 minutes. They use positive locking wire spring retainers. Just pull the retainer up and pull the hose off. Cold of course. Also make sure you do a very good visual inspection to the tank. Tanks are a known failure item on the M54 motors.
	Appreciate 0 Quote

07-10-2012, 04:03 PM	#6
NYZ4Jack Private 20 Rep 94 Posts Drives: 2005 Z4 3.0i Join Date: Nov 2011 Location: New York, NY iTrader: (0)	YOU are the MAN!!! Just saved me a bunch of time and money. Thanks for the tip! I'm going to change the expansion tank with a new one as a precaution. I can pick up the O-rings from Home Depot or Autozone. Material of O-ring matter?
	Appreciate 0 Quote