Engine Temp Drops When Heater Is Turned On - BMW Forum - BimmerWerkz.com
BMW Forum BMW Forum

Ľ Auto Insurance

» Featured Product
Ľ Wheel & Tire Center

Go Back   BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 3-Series (E36)
Register Home Forum Active Topics Gallery / Showroom Auto Loans Garage Search Today's Posts Mark Forums Read Auto EscrowInsurance

3-Series (E36) Chat relating to the BMW 3-Series from 1992-1999. Autodoodad Specific models include: BMW 316i, BMW 318i, BMW 318iS/ti, BMW 320, BMW 323, BMW 320, BMW 324, BMW 325, BMW 328.

BimmerWerkz.com is the premier BMW Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 10-01-2004, 09:09 PM   #1 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
I've got a 97 328iS that I bought in may. Since it's mid fall in upstate NY, the heater is starting to get some use for the first time since I bought the car. When I turn the heat on, the engine temps drops down from the middle of the gauge down to the blue section. The heat being blown out also gets cooler and cooler as the engine temp drops.

At first I thought that maybe my thermostat was fried open. But if that were the case, my engine temp would be all over the place. Ever since I bought the car, I've never seen the temp move from the middle of the gauge oncethe engine was warm. It doesn't matter if it's 110 and I'm sitting in traffic, the temp stays constant.


What the hell is wrong?


wulley1 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 10-02-2004, 06:27 AM   #2 (permalink)
1st Gear Member
 
Join Date: May 2004
Car:
Posts: 229
Photos:
Fadec40 is an unknown quantity at this point
Well, if the thermostat was stuck open, which is usually how they fail. your temp would never get that high because coolant is always flowing. , Hence no heat. You might want to look at the coolant temperature gauge senders (sensors) as well. I would first take a look at the thermostat, then take it from there.
Fadec40 is offline   Reply With Quote
Old 10-02-2004, 08:58 AM   #3 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
I thought the middle of the temp gauge was were the engine was supposed to be at. It's always there and never moves....until you crank the heat.
wulley1 is offline   Reply With Quote
Old 10-02-2004, 11:01 AM   #4 (permalink)
2nd Gear Member
 
Join Date: Jul 2004
Location: NYC
Car:
Posts: 449
Photos:
NeverLeaned is an unknown quantity at this point
Send a message via AIM to NeverLeaned
Quote:
Originally posted by wulley1@Oct 2 2004, 07:58 AM
I thought the middle of the temp gauge was were the engine was supposed to be at. It's always there and never moves....until you crank the heat.
[snapback]203395[/snapback]
I would expect a modest drop in the temp if you crank the heat.
Cranking the heat is a common technique for helping engine overheating problems until you can get the car serviced.

Not sure where to look first the problem though. I had an old toyota in college. Changed the coollant and the temp was always too low. (had to put a piece of cardboard in front of the radiator to keep the temp high enough to make heat in winter. (ya it was pretty ghetto )

The next year when I changed the coolant again, the problem disappeared and it went back to normal operating temps. Still have no idea what happened there, but I guess it had something to do with my coolant mixture. (only thing I ever changed) This is a needle in a haystack idea, I would suggest you look elsewhere before you change coolant.
__________________
1996- BMW 328IS
<img src='http://img.photobucket.com/albums/v242/gws226/TEX/neverleanedsig.jpg' border='0' alt='user posted image' />
Performance: Zimmerman Cross Drilled Rotors-- PBR Deluxes-- Cosmos CAI---- Turner Pulley Kit--- Fan Delete mod---
Beauty: 18 polished M-Parallel replicas, Inpro Euros w/ Enchanced Angel eye kit, 20% tint
Clear corners/sidemarkers ---- Eurospec (Depos)

To do list:
Suspension--- researching
UUC System U TDM- 3/05
M50 manifold converstion 3/05
off to the tuning shop for custom software 4/05
Cams/lightened flywheel, throttlebody........ well lets see what happens
NeverLeaned is offline   Reply With Quote
Old 10-02-2004, 01:58 PM   #5 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
I've thought about draining the coolant.
wulley1 is offline   Reply With Quote
Old 10-02-2004, 02:11 PM   #6 (permalink)
1st Gear Member
 
Join Date: Sep 2004
Car:
Posts: 254
Photos:
Brian325i is an unknown quantity at this point
I read that when you turn the heater on, it opens up the thermostat because the engine is having to work a little harder to heat the air.
Brian325i is offline   Reply With Quote
Old 10-03-2004, 10:14 AM   #7 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
driving home from rochester this morning, it was pretty cool outside, maybe in the mid forties. I was traveling at about 85mph wit hthe cruise set. The engine temp just made it out of the blue, and that was with the heat turned off.

While I am glad the engine is running to cool instead of too hot, I still really want to fix the problem. But I'm pretty baffled now.
wulley1 is offline   Reply With Quote
Old 10-03-2004, 11:11 AM   #8 (permalink)
5th Gear Member
 
billB's Avatar
 
Join Date: Aug 2004
Location: New Jersey
Car:
Posts: 1,635
Photos:
billB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond reputebillB has a reputation beyond repute
Send a message via Yahoo to billB
Wulley1

change the thermostat. It is wide open. and thermostats don't heat the air inside the car and engines don't work harder to heat inside the car either. At least not the way it is described above.

This is how it works:
thermostat normal position is closed when engine is cold. you start engine and after a little while thermostat opens up (the timing of when to open up is temp. dependant i.e when you take thermos. out read the fine lettering on it you'll see numbers these numbers are the temp. at which this thermostat must open when reached (spring loaded mechanism type of a deal ) ; allowing coolant to circulate). Now if it does not open (closed path/no circulation))=overheated engine; if it stays wide opens (open path/full blown circulation like your car) = engine has to heat the entire coolant before heat reaches certain tem. and your interior in the form of hot air. Heating the inside is another matter without details: though it is hot coolant dependant the heating core under you dash is responsible. Hot coolant flows through it (in and back out controlled by valves NOT THE THERMOSTAT) blower hits it then hot air gets inside through your vents.
Now think: you did 85 MPH on NY thruway coupled with temp. of 43 degrees while the entire coolant is circulating to radiater (wide open thermostat)......there is no way on earth your engine will be able to heat the coolant WITH A WIDE OPEN THERMOSTAT in fact the faster you go the cooler it will get. Try this, stop and idle for 20 minutes or so you'll see a rise in the temp and thus hotter air inside.

p.s. there is also a temp. controlling switch which inputs some info. in the above process

I hope this helps you out to sort your problem but this is another story
regards
billb
billB is offline   Reply With Quote
Old 10-03-2004, 11:50 AM   #9 (permalink)
2nd Gear Member
 
Join Date: Jul 2004
Location: NYC
Car:
Posts: 449
Photos:
NeverLeaned is an unknown quantity at this point
Send a message via AIM to NeverLeaned
Maybe its just coincedence.......... but perhaps your thermostat went at on the same day it started getting cold.
__________________
1996- BMW 328IS
<img src='http://img.photobucket.com/albums/v242/gws226/TEX/neverleanedsig.jpg' border='0' alt='user posted image' />
Performance: Zimmerman Cross Drilled Rotors-- PBR Deluxes-- Cosmos CAI---- Turner Pulley Kit--- Fan Delete mod---
Beauty: 18 polished M-Parallel replicas, Inpro Euros w/ Enchanced Angel eye kit, 20% tint
Clear corners/sidemarkers ---- Eurospec (Depos)

To do list:
Suspension--- researching
UUC System U TDM- 3/05
M50 manifold converstion 3/05
off to the tuning shop for custom software 4/05
Cams/lightened flywheel, throttlebody........ well lets see what happens
NeverLeaned is offline   Reply With Quote
Old 10-03-2004, 01:16 PM   #10 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
it's certainly worth trying to replace it. It's an inexpensive part, and certainly wouldn't to have a new one on even if it's not wore out yet.

I've never changed one on an e36, anyone seen a DIY?
wulley1 is offline   Reply With Quote
Old 10-03-2004, 01:32 PM   #11 (permalink)
Been here a while.
 
97alpineM3's Avatar
 
Join Date: May 2004
Location: Virginia
Car: Blah
Posts: 5,375
Photos:
97alpineM3 is a name known to all97alpineM3 is a name known to all97alpineM3 is a name known to all97alpineM3 is a name known to all97alpineM3 is a name known to all97alpineM3 is a name known to all
Send a message via AIM to 97alpineM3 Send a message via MSN to 97alpineM3
yes.. go to pelicanpart.com click through the first couple of pages.. and then look at some of their tech articles.. there are many DIY pages.. good luck... trust me.. there is a thermostat page too...

Good Luck

Its not hard..

Les
__________________

1997 E36 M3 1990 E30 325i
97alpineM3 is offline   Reply With Quote
Old 10-03-2004, 04:30 PM   #12 (permalink)
3rd Gear Member
 
Join Date: May 2004
Car:
Posts: 628
Photos:
wulley1 is an unknown quantity at this point
Doesn't seem like it would be too hard. It'll give me an excuse to drain the coolant and change that at the same time.

What coolant am I supposed to use?
wulley1 is offline   Reply With Quote
Old 10-04-2004, 08:07 AM   #13 (permalink)
4th Gear Member
 
93 325i's Avatar
 
Join Date: Sep 2004
Location: Connecticut
Car:
Posts: 921
Photos:
93 325i is an unknown quantity at this point
Send a message via AIM to 93 325i
Just adding my 2 cents..My old car 1995 318i, had the same exact problem. Turn the heat on- engine temp drops & heat gets cooler and cooler..It was the termostat. Changed it and problem was gone
__________________
Complete mod list and pics:

My 1993 325i
93 325i is offline   Reply With Quote
Old 10-04-2004, 10:00 AM   #14 (permalink)
2nd Gear Member
 
Join Date: Sep 2004
Car:
Posts: 358
Photos:
bad man working is an unknown quantity at this point
I havenít read all the replies, but I can tell you BMW had a major problem with their thermostats this effected M43, M52 and M54 engine for a long period of time the thermostats donít just fail open they break and have no effect. Depending on climate road conditions driving style ambient temp etc the engine may run at normal operating temp some times.
Iím an English BMW tech and the rule coolant in this country is Ė 50ļC normally a 50% antifreeze to water mix but check the bottle

Hope this helps

Bad Man Working
bad man working is offline   Reply With Quote
Old 11-20-2007, 09:32 PM   #15 (permalink)
Neutral Member
 
Join Date: Jul 2007
Car:
Posts: 80
Photos:
hyper_cool is on a distinguished road
Hi Wulley,
I'm just curious, did replacing of your thermostat fixed your problem? I'm having the same issue & I just want to confirm the fix suggested such as replacing thermostat fixed the issue. Please kindly reply back. Thanks.
hyper_cool is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

  BMW Forum - BimmerWerkz.com > BMW Model Specific Forums > 3-Series (E36)


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Synthetic Oil and filter CiscoKid 3-Series (E36) 47 04-14-2014 06:00 PM
Erratic Idle / Misfire / Cutting out makdolby 3-Series (E36) 12 02-05-2012 07:57 AM
Heater Core ? walshja 3-Series (E36) 8 01-19-2005 05:39 PM
Engine Overheating/Cold air from Heater Bluebonnet 5-Series (E12,E28, E34, E39, E60) 6 12-17-2003 06:41 PM

Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 03:15 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.3.2
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.