E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 07-22-2011, 04:15 PM   #1
wroberts
Registered User
 
Join Date: Jul 2011
Location: United States
Posts: 2
My Ride: 323Ci
How to test a thermostat?

My 2000 323Ci has been occasionally overheating and since I have recently replaced the water pump and thoroughly bled the air out of the cooling system according to e46fanatics standards, I believe that the thermostat on my car may be stuck shut. I was wondering how I would go about testing the thermostat to make sure that it is faulty before replacing it. So if anyone has a method of testing, please tell. Thanks
wroberts is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 07-22-2011, 04:26 PM   #2
jgold47
Registered User
 
Join Date: Sep 2010
Location: Imported from Detroit
Posts: 1,262
My Ride: 2004 X5 3.0
it usually sticks open....that said, there is probably a way to test. Its a realatively cheap replacement, and not a terrible DIY. I did it in about an hour in 15deg weather. Probably worth replacing.
__________________
Religion, Politics, and which oil is the best to use. Three things never to be discussed in polite company...

my about me link
http://forum.e46fanatics.com/showthread.php?t=791566

jgold47 is offline   Reply With Quote
Old 07-22-2011, 04:26 PM   #3
RossGuy
E46Fanatic
 
Join Date: May 2011
Location: Illinois
Posts: 223
My Ride: FBM
I believe you can put it in a pot of water and see if it opens when the water reaches that temp.
__________________
Quote:
Originally Posted by NFRs2000nyc View Post
Shut up and drink your snow from your plastic cup you hungry homeless homosexual.
RossGuy is offline   Reply With Quote
Old 07-22-2011, 04:28 PM   #4
RockLee
Registered User
 
Join Date: Mar 2008
Location: Vero Beach FL.
Posts: 2,239
My Ride: 99 328i. ZSP, ZPP,
Send a message via Yahoo to RockLee Send a message via Skype™ to RockLee
This is an electric thermostat. So don't boil the connectors.
__________________

1999 328i Sport Package, Premium Package, 5 speed, Alpine white.
RockLee is offline   Reply With Quote
Old 07-22-2011, 04:30 PM   #5
RossGuy
E46Fanatic
 
Join Date: May 2011
Location: Illinois
Posts: 223
My Ride: FBM
My bad. Still new to the BMW world so was going off old knowledge.
__________________
Quote:
Originally Posted by NFRs2000nyc View Post
Shut up and drink your snow from your plastic cup you hungry homeless homosexual.
RossGuy is offline   Reply With Quote
Old 07-22-2011, 05:00 PM   #6
LivesNearCostco
Registered User
 
Join Date: Jan 2010
Location: Silicon Valley
Posts: 768
My Ride: 2003 ZHP 6MT
I thought about boiling mine since by the time I suspected it was stuck shut, the electrical heater circuit had already fried itself. Since the thermostat was on the car, I tried this instead:
  1. Bleed cooling system and remove main fan (Auto) or only fan (MT)
  2. For bonus points, unlock hidden OBC menu to watch coolant temp on instrument cluster
  3. Start car and drive around until temp gauge is in middle
  4. When temp gauge climbs beyond middle turn heater to 91F, fan high, vent dial to 3 red dots to prevent overheating since the heater core acts like a mini radiator. Do NOT let gauge go into the red zone.
  5. Park car, feel upper and lower radiator hoses plus radiator. WARNING, may be hot enough to burn you
  6. Replace thermostat if needed. Rebleed if you replace thermostat.
  7. Repeat test to make sure new thermostat opens when car is at operating temp
  8. Put fan back on.

If upper hose is hot while lower hose and radiator are cold, your thermostat is probably stuck closed. But since it's supposed to be closed when the car is cold, you have to let the car warm up first before checking the hose temps.
LivesNearCostco is offline   Reply With Quote
Old 07-22-2011, 05:43 PM   #7
ZHPRegistry
Past Site Sponsor
 
Join Date: Jun 2011
Location: Searching for GPS...
Posts: 74
My Ride: was a bit tiresome
Can you tell us specific conditions under which it overheats? Does it ever happen when you are traveling over 40MPH? Some of these signs may help you to identify the problem without needing to take the thermostat off. In my opinion if you are going to test the stat by removing, might as well just get a new one (depending on how old it is).
ZHPRegistry is offline   Reply With Quote
Old 07-22-2011, 05:53 PM   #8
wroberts
Registered User
 
Join Date: Jul 2011
Location: United States
Posts: 2
My Ride: 323Ci
Currently it's pretty hot in Ga. My car only overheats when stopped, and when I start driving again it will cool down. It doesn't overheat every time I stop, but sometimes. I generally just blast the heat in my car and the engine cools down.
wroberts is offline   Reply With Quote
Old 07-22-2011, 05:56 PM   #9
ZHPRegistry
Past Site Sponsor
 
Join Date: Jun 2011
Location: Searching for GPS...
Posts: 74
My Ride: was a bit tiresome
Quote:
Originally Posted by wroberts View Post
Currently it's pretty hot in Ga. My car only overheats when stopped, and when I start driving again it will cool down. It doesn't overheat every time I stop, but sometimes. I generally just blast the heat in my car and the engine cools down.
It's not your thermostat. It's your fan clutch getting weak. With the stat stuck closed the temp will rise even if you are moving fast.
ZHPRegistry is offline   Reply With Quote
Old 07-22-2011, 07:41 PM   #10
LivesNearCostco
Registered User
 
Join Date: Jan 2010
Location: Silicon Valley
Posts: 768
My Ride: 2003 ZHP 6MT
Agree with ZHPRegistry. Ignore my thermostat test plan. If you have an AT, it's your fan clutch. If you have MT, it's either temp sensor in lower radiator hose or relay for electric fan.
LivesNearCostco is offline   Reply With Quote
Old 07-22-2011, 09:35 PM   #11
iansanderson
Registered User
 
Join Date: Feb 2009
Location: Northeast Ohio
Posts: 2,778
My Ride: 2001 330CiC
Quote:
Originally Posted by wroberts View Post
Currently it's pretty hot in Ga. My car only overheats when stopped, and when I start driving again it will cool down. It doesn't overheat every time I stop, but sometimes. I generally just blast the heat in my car and the engine cools down.
sounds like an air movement problem. are the fans working?
__________________



Cheat Sheet:

GT1/ISIS/MoDiC = Factory authorized diagnostic system used by BMW dealerships across the world.

NCS Expert = BMW Factory R&D programming tool available on the internet (not intended for the public and not available to the dealership network)

OEM = Genuine BMW part only available from a franchised BMW dealership.

DME = Engine Management Computer
iansanderson is offline   Reply With Quote
Old 08-08-2011, 06:54 AM   #12
denziano
Registered User
 
Join Date: Oct 2009
Location: montreal
Posts: 5
My Ride: 325i
fan clutch problem

hey guys, i need u'r expert opinions. Are these fan clutches reliable? What causes the fan clutch to burn out? This is my second one it lasted 80k, is this normal?
THX

Last edited by denziano; 08-08-2011 at 06:55 AM.
denziano is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Censor is ON





All times are GMT -5. The time now is 05:41 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use