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 > Z Series > E85 / E86 Z4 (2003-2008)

E85 / E86 Z4 (2003-2008)
E85 Z4 Roadster, E86 Z4 Coupe, E85 Z4 M Roadster, and E86 Z4 M Coupe talk with our BMW gurus here.

Reply
 
Thread Tools Display Modes
  #1  
Old 08-07-2012, 04:01 PM
'04Z4 Texas '04Z4 Texas is offline
Registered User
Location: San Antonio, TX
 
Join Date: Aug 2012
Posts: 1
Mein Auto: BMW '04 Z4
overheating '04 Z4

My '04 Z4 is overheating. I took it to a dealer and they replaced the sensor sending unit. The car still overheats. Fans are working. Coolant is full. Any suggestions? I also realized the temperature gauge is actually more like a switch than a gauge. It jumps in increments when the car gets hot. (buffered?) anyone have experience with this? Car only has 60k on it and has been well maintained. I don't want to take a shotgun approach to the issue and start replacing a bunch of parts needlessly.
Reply With Quote
Advertisement
  #2  
Old 08-07-2012, 04:30 PM
wifesauto wifesauto is offline
Officially Welcomed to the 'Fest
Location: nj
 
Join Date: Jan 2012
Posts: 336
Mein Auto: sloporsche
many many things to check. thermostat,radiator plugged[inside /outside] ,water pump [flow] hose flattening. head gasket
Reply With Quote
  #3  
Old 08-07-2012, 05:32 PM
ZEEBOY ZEEBOY is offline
Officially Welcomed to the 'Fest
Location: SW Ohio
 
Join Date: Nov 2006
Posts: 155
Mein Auto: 2001 Z3 Coupe and 2003 Z4
Jumping in increments often means air in the coolant system. But, that does not just happen for no reason...usually the result of improper filling after waterpump or thermostat replacement...
Reply With Quote
  #4  
Old 08-07-2012, 06:17 PM
acoste acoste is offline
Officially Welcomed to the 'Fest
Location: California
 
Join Date: Nov 2011
Posts: 465
Mein Auto: 1998 528i; 2010 550i
The position of the gauge is not linear to the measured temperature. It stays in the middle for a wide range, something like 80-115 Celsius and then rapidly moves to the right.
Watch the real temperature value
(I can do that on my model when I unlock the instrument panel by pushing the reset button in a specific way)
Does the overheating happen at traffic lights, in the city or on the highways?


Sent from my ADR6350 using Bimmer App
Reply With Quote
  #5  
Old 08-07-2012, 07:32 PM
chickdr chickdr is offline
Officially Welcomed to the 'Fest
Location: Atlanta, GA
 
Join Date: Mar 2009
Posts: 1,073
Mein Auto: '06 M Roadster Imola/Blk
How many miles on the car? It may just need a cooling system overhaul? New radiator, hoses, water pump, thermostat. Newer BMW's supposedly need the systems done every 50-100k.
Reply With Quote
  #6  
Old 08-08-2012, 04:18 AM
Mikey48 Mikey48 is offline
Officially Welcomed to the 'Fest
Location: Charleston,S.C.
 
Join Date: Mar 2011
Posts: 425
Mein Auto: BMW Z4 3.0
I agree with ZEEBOY. If your gauge is jumping around there could be air in your cooling system. Is your water at the right level in the rad ? The stick you see rise after you remove the rad cap should rise to the 2nd ball on the stick to the rad inlet no further ! Also double check your hoses. My 2004 Z4 3.0i had a hose go bad and started leaking after I would turn the car off. It turned out to be the top rad hose was bad.I replaced it flushed my cooling system making sure to get all the air out of the cooling system. You have to remove the shroud at the top of the rad to get to the bleeder screw. Some cars will burp themselfs if you start the car when it is cold and let it idle with the rad cap off and let it idle up to temperature. Keeping a close eye on your temp gauge. DO NOT drive your car if it is running hot ! You will kill your car !!! This is where I would start. Good luck !
Reply With Quote
  #7  
Old 08-08-2012, 04:35 AM
crewdog843's Avatar
crewdog843 crewdog843 is offline
Officially Welcomed to the 'Fest
Location: Las Vegas, NV
 
Join Date: Mar 2006
Posts: 672
Mein Auto: '08 Z4 3.0si Roadie
So the dealer replaced the sending unit without testing the car to see if would overheat afterwards...shoddy workmanship. You may have to bleed the system as you may have air trapped in it. Don't forget to put the heating control for the cabin to full hot, and park on a slight incline. BTW: What caused it to start overheating in the first place?

jake
__________________
Reply With Quote
  #8  
Old 08-08-2012, 05:08 AM
brock5ga brock5ga is offline
Registered User
Location: Monroe, GA
 
Join Date: May 2012
Posts: 96
Mein Auto: Z4
BMW has had problems with the plastic impellers on the water pumps. There are aftermarket versions available with metal impellers. Check in order 1) Air in system 2) Water pump impeller ( I usually use the small hose to the reservoir to check for flow, but I don't see one on my 03 unless it is under the cover) 3) Blown head gasket (Usually results in pushing water out of system. Should notice visible water loss.) My guess is the water pump.
Reply With Quote
Reply

Bookmarks

Tags
coolant, overheating, temp gauge, z4


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > Z Series > E85 / E86 Z4 (2003-2008)
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 09:45 AM.


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