Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 01-01-2009, 08:40 PM
hokiehigh hokiehigh is offline
Officially Welcomed to the 'Fest
Location: Greenwich, CT
 
Join Date: Jun 2005
Posts: 151
Mein Auto: 2003 540i MSport
Need help replacing coolant temp sensor

I discovered a paddle of coolant on the garage floor and it seems come from the coolant temp sensor. I have no idea how to get to it since it's pretty far down. Do I have to drain the coolant and take out the fan/shroud to reach the sensor?

the sensor is #12 in below diagram.

http://www.realoem.com/bmw/showparts...67&hg=11&fg=35

Or will it be easier to jack up the car and reach from down below? How to take off belly pan?

Many thanks!
__________________
2003 540iA M-Sport Black/Tan
Reply With Quote
Ads by Google
  #2  
Old 01-01-2009, 08:48 PM
Adrian H's Avatar
Adrian H Adrian H is offline
"Wait... What's this do?"
Location: Colorado Springs, CO
 
Join Date: Jul 2008
Posts: 790
Send a message via AIM to Adrian H
Mein Auto: 1997 528i
Check therough the DIY section of the forums, there's a V8 Walkthrough posted by CN90
__________________
05/1997 Alpine White 528i Debadged, Intake Muffler Delete [Sold, Died of the E39itis]
Current - 07 Hyundai Accent, The Family Car!
Quote:
Originally Posted by taylormiles View Post
Heh. Well, you should know if its a touring. It would have a very large badonkadonk.
Reply With Quote
  #3  
Old 01-01-2009, 10:04 PM
BlackBMWs's Avatar
BlackBMWs BlackBMWs is offline
Check twice, fix once...
Location: Sacramento, CA
 
Join Date: Nov 2008
Posts: 727
Mein Auto: 540it 533i 318ic 325i
Hokiehigh,

While I have a 1999 540it, I believe our Water Temp (WT) sensors are the same.



I can reach the sensor from the top of the engine compartment. I'd do this with the system coolant cold. I'd remove the belly pan and use a collection pan to collect spilled coolant. Personally, I'd probably drain the system before I pulled the sensor, just cause I would not want coolant in places it might spill/shoot into. Don't want to create a different electrical problem. I suppose if you leave the coolant tank cap on the flow might be lessened.

Someone may have a better procedure, but if you didn't want to drain the cooling system, here's what I'd do. Let us know which way you proceed.

----------------------------------------------------------------------------------------------------

1. Remove the belly pan. Belly pan removal requires clearance and a Phillips screwdriver. 7 to 9 screws around the perimeter of the pan. Once all the screws are removed, shift the belly pan to the rear to clear the bottom of the front bumper cover. Place a suitable pan underneath the lower radiator hose to collect coolant loss. (Whether you are totally draining the system or just gonna try to be quick.)

2. Prepare the o-ring on the new sensor. I lightly coated mine with dialetric grease. I believe someone else used Vaseline.

3. Remove the airbox for access clearance to the sensor.

4. Remove the sensor wiring connector on the old sensor by pulling back the sensor retaining clip, then pulling the wiring connector upward.



5. Prepare for coolant loss. Protective eyewear would be good here. Squeeze the WT sensor ears and pull upward. Be mindful you may have a small geyser of coolant.

Coolant will flow out of the hose as this is the lowest coolant point in the system. I suppose if you're quick and ready you could do it with a minimum of coolant loss.

6. Put the new sensor in quick and careful.

7. Reverse connect everything back together. (Except Belly Pan)

8. Refill loss coolant with 50/50 mix of new coolant and distilled water. Turn on ignition, but not engine, set heater to highest temperature with fan on lowest position to turn on aux coolant pump to get flow in system while topping off.

9. Wipe down what you can and check for leaks. If there are none, reinstall Belly pan.

10. Cruise around a bit, then when cooled off, recheck coolant level.

11. Enjoy suitable beverage...

When was the last time you changed your coolant? If more than a few seasons, might be a good time to flush it out and change it anyway. There are various opinions on coolant choices, I just went with the OEM coolant when I did my overhaul recently. 1.5 gal coolant with 1.5 gal distilled water.

I'm certain someone will chime in if I've missed something... Good luck!
__________________

1999 540it - Jet Black/Sand Beige, style 5 rims, Zionsville Cooling kit
1984 533i - Schwarz/Schwarz, 17" style 65 reps
1997 318ti Sport - Schwartz II/Schwartz Anthratz, style 68 rims
1995 318ti Sport - Schwartz II/Schwartz Anthratz, style 27 rims
1994 325i Sedan - Bostongrau/Tan
1991 318ic - Schwarz/Anthratz Stoff
1985 635CSI - Schwartz\Sand - Sold
1984 318i - Champagne/Tan, Stock - Sold

BMWCCA# 160411

Last edited by BlackBMWs; 01-02-2009 at 12:34 AM.
Reply With Quote
  #4  
Old 01-02-2009, 07:38 AM
hokiehigh hokiehigh is offline
Officially Welcomed to the 'Fest
Location: Greenwich, CT
 
Join Date: Jun 2005
Posts: 151
Mein Auto: 2003 540i MSport
Thanks very much, BlackBMWs! Your instruction is better than I hoped for. I'll put the car on ramps this weekend (hopefully the weather is not too cold) and take off the belly pan to have a closer look.
Most of the cooling system parts were replaced in the past two years, the coolant was drained last year when replacing expansion tank. I'll try to replace just the sensor as quickly as possible then refill.
Will update later. Thanks again.
__________________
2003 540iA M-Sport Black/Tan
Reply With Quote
  #5  
Old 01-02-2009, 08:48 AM
BlackBMWs's Avatar
BlackBMWs BlackBMWs is offline
Check twice, fix once...
Location: Sacramento, CA
 
Join Date: Nov 2008
Posts: 727
Mein Auto: 540it 533i 318ic 325i
Quote:
Originally Posted by hokiehigh View Post
Thanks very much, BlackBMWs! Your instruction is better than I hoped for. I'll put the car on ramps this weekend (hopefully the weather is not too cold) and take off the belly pan to have a closer look.
Most of the cooling system parts were replaced in the past two years, the coolant was drained last year when replacing expansion tank. I'll try to replace just the sensor as quickly as possible then refill.
Will update later. Thanks again.
You're welcome, hope it helps. BTW, I did try to get a replacement o-ring, (Green one) and BMW does not stock it separately. The new WT sensor cost me about $30 after CCA discount.
__________________

1999 540it - Jet Black/Sand Beige, style 5 rims, Zionsville Cooling kit
1984 533i - Schwarz/Schwarz, 17" style 65 reps
1997 318ti Sport - Schwartz II/Schwartz Anthratz, style 68 rims
1995 318ti Sport - Schwartz II/Schwartz Anthratz, style 27 rims
1994 325i Sedan - Bostongrau/Tan
1991 318ic - Schwarz/Anthratz Stoff
1985 635CSI - Schwartz\Sand - Sold
1984 318i - Champagne/Tan, Stock - Sold

BMWCCA# 160411
Reply With Quote
  #6  
Old 01-03-2009, 09:45 AM
BlackBMWs's Avatar
BlackBMWs BlackBMWs is offline
Check twice, fix once...
Location: Sacramento, CA
 
Join Date: Nov 2008
Posts: 727
Mein Auto: 540it 533i 318ic 325i
Someone mentioned on another post that you should use Silicone on the o-ring, not Vaseline. I've only used dialetric grease, so I never used Vaseline anyway.
__________________

1999 540it - Jet Black/Sand Beige, style 5 rims, Zionsville Cooling kit
1984 533i - Schwarz/Schwarz, 17" style 65 reps
1997 318ti Sport - Schwartz II/Schwartz Anthratz, style 68 rims
1995 318ti Sport - Schwartz II/Schwartz Anthratz, style 27 rims
1994 325i Sedan - Bostongrau/Tan
1991 318ic - Schwarz/Anthratz Stoff
1985 635CSI - Schwartz\Sand - Sold
1984 318i - Champagne/Tan, Stock - Sold

BMWCCA# 160411
Reply With Quote
  #7  
Old 01-06-2010, 03:06 PM
hopeitsapar2 hopeitsapar2 is offline
Registered User
Location: Indy
 
Join Date: May 2009
Posts: 13
Mein Auto: 200 528i
Would this proceedure be the same for a 528i?
Reply With Quote
  #8  
Old 08-06-2010, 01:14 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,082
Mein Auto: 02 BMW 525i M54 auto 130K
As a helpful xref, in the alternator & cooling system thread ... I measured a new FAE coolant temperature sensor o-ring at 0.330" ID by 0.115" thick (i.e., 8mmIDx3mmThick) which is the same 8x3 size as the BMW PN 13621743299 intake manifold air temperature sensor. It apparently fits all E39 and E46 vehicles; I'd recommended adding it to your cooling system overhaul recommended parts list.

Reply With Quote
  #9  
Old 12-04-2010, 02:27 PM
Westlotorn Westlotorn is offline
Officially Welcomed to the 'Fest
Location: Folsom, CA
 
Join Date: Sep 2007
Posts: 133
Mein Auto: 1966 Vette 2008 X5 4.8L
O'rings are available at almost all parts stores, they come in both metric and inch sizes. If one store does not have the right ones just go down the street to the next one. O'Rings are not an issue to buy.
Lubricate Orings with the product they are sealing, in this case use antifreeze. Some oils or petrolium products will cause the Orings to swell which can be a big problem.
Reply With Quote
  #10  
Old 12-04-2010, 07:34 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,082
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by Westlotorn View Post
O'Rings are not an issue to buy
Realizing this is an old thread, resurrected today ... let us be clear ...

Everything the OP can possibly want to know about the coolant temperature sensor o-ring is in this E39 thread.
- Next person to replace coolant temperature sensor: Please measure the O-ring size!
Reply With Quote
  #11  
Old 12-06-2010, 11:50 AM
Westlotorn Westlotorn is offline
Officially Welcomed to the 'Fest
Location: Folsom, CA
 
Join Date: Sep 2007
Posts: 133
Mein Auto: 1966 Vette 2008 X5 4.8L
Quote:
Originally Posted by bluebee View Post
Realizing this is an old thread, resurrected today ... let us be clear ...

Everything the OP can possibly want to know about the coolant temperature sensor o-ring is in this E39 thread.
- Next person to replace coolant temperature sensor: Please measure the O-ring size!
Using an Inch Micrometer the Oring is as follows.
Outer Diameter = OD Inner Diameter = ID
OD .530 inches 13.462mm 14mm is .551inches.
ID .325 or 8 mm
Thickness = .118 or 3mm

The O ring measured was used so I believe it has taken a set at 13.462mm rather than the new condition of 14mm.

The sensor O ring flange measures .330 ID and .510 OD

To double check:
8mm is ID + 3mm +3mm = OD of 14mm
you have to add both widths when you measure an o ring Outside Diameter. So ID plus width one and Width 2 equals the total size of the oring.

You are looking for an Oring that is 14mm OD and 3mm width.

http://www.theoringstore.com/servlet...-Metric/Detail
Reply With Quote
  #12  
Old 12-06-2010, 01:12 PM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
 
Join Date: Mar 2008
Posts: 21,082
Mein Auto: 02 BMW 525i M54 auto 130K
Quote:
Originally Posted by Westlotorn View Post
Using an Inch Micrometer the Oring is as followsl
Thanks for this data today; I'll add it to the coolant temperature sensor o-ring thread.

Reply With Quote
  #13  
Old 11-20-2013, 03:13 PM
Canuckgold Canuckgold is offline
Registered User
Location: Canada
 
Join Date: Mar 2009
Posts: 4
Mein Auto: BMW540i
Quote:
Originally Posted by BlackBMWs View Post
Hokiehigh,

While I have a 1999 540it, I believe our Water Temp (WT) sensors are the same.



I can reach the sensor from the top of the engine compartment. I'd do this with the system coolant cold. I'd remove the belly pan and use a collection pan to collect spilled coolant. Personally, I'd probably drain the system before I pulled the sensor, just cause I would not want coolant in places it might spill/shoot into. Don't want to create a different electrical problem. I suppose if you leave the coolant tank cap on the flow might be lessened.

Someone may have a better procedure, but if you didn't want to drain the cooling system, here's what I'd do. Let us know which way you proceed.

----------------------------------------------------------------------------------------------------

1. Remove the belly pan. Belly pan removal requires clearance and a Phillips screwdriver. 7 to 9 screws around the perimeter of the pan. Once all the screws are removed, shift the belly pan to the rear to clear the bottom of the front bumper cover. Place a suitable pan underneath the lower radiator hose to collect coolant loss. (Whether you are totally draining the system or just gonna try to be quick.)

2. Prepare the o-ring on the new sensor. I lightly coated mine with dialetric grease. I believe someone else used Vaseline.

3. Remove the airbox for access clearance to the sensor.

4. Remove the sensor wiring connector on the old sensor by pulling back the sensor retaining clip, then pulling the wiring connector upward.



5. Prepare for coolant loss. Protective eyewear would be good here. Squeeze the WT sensor ears and pull upward. Be mindful you may have a small geyser of coolant.

Coolant will flow out of the hose as this is the lowest coolant point in the system. I suppose if you're quick and ready you could do it with a minimum of coolant loss.

6. Put the new sensor in quick and careful.

7. Reverse connect everything back together. (Except Belly Pan)

8. Refill loss coolant with 50/50 mix of new coolant and distilled water. Turn on ignition, but not engine, set heater to highest temperature with fan on lowest position to turn on aux coolant pump to get flow in system while topping off.

9. Wipe down what you can and check for leaks. If there are none, reinstall Belly pan.

10. Cruise around a bit, then when cooled off, recheck coolant level.

11. Enjoy suitable beverage...

When was the last time you changed your coolant? If more than a few seasons, might be a good time to flush it out and change it anyway. There are various opinions on coolant choices, I just went with the OEM coolant when I did my overhaul recently. 1.5 gal coolant with 1.5 gal distilled water.

I'm certain someone will chime in if I've missed something... Good luck!
I have to say these instruction saved me a ton of grief and dough. They were spot on right down to the beverage at the end. I would like to add that I was going to drain the coolant but I couldn't get the drain plug out. Rather than risking a breakage, I figured I'd take the sensor out and plug the hole while replacing the 'O' ring. The sensor was working so why pay through the nose to replace it. Anyway, when I took the sensor out, the coolant didn't flood out of the connection as expected. I did have something ready to plug the hole temporarily but it wasn't needed. I picked up a new 'O' ring from the dealer for the outrageous price of $8.61 Canadian, swapped it out and put everything back together. No more leak so I'm a happy camper.

CG
Reply With Quote
  #14  
Old 11-20-2013, 03:36 PM
Flounderasu Flounderasu is offline
Officially Welcomed to the 'Fest
Location: Arizona
 
Join Date: Jun 2013
Posts: 116
Mein Auto: 2003 - 540i M-Sport
Yeah, these directions were spot on except for a few things:

#1. You don't need to remove the underpan
#2. Don't open up any other part of the cooling system, otherwise you coolant will gush out.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 03:45 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms