Page 1 of 2 12 LastLast
Results 1 to 25 of 40

Thread: electric engine fan issues..

  1. #1
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997

    electric engine fan issues - solved

    (sorry for my bad english at first..)

    I'm having troubles with the electrin fan (no viscostatic, only 2-speed electric fan) on my M44 engine. When I put on AC the vent will have to start as long as the AC is on...isn't right?
    On other hand the vent starts and stops, seems at regular intervals, and I don't know why. And last night I was with the car parked, with engine on and AC shut off.

    After some minutes I looked the temp..it was slightly oevr the middle! Panic.
    Shut off immediately the car, tried to look at the liquid level: ok. But the vent didn't started working.

    This morning tried to start the vent closing the contact on the wires, it started correctly. Then tried to leave the engine on to verity it will start at correct temperature: it works fine.
    What's happening with the cooling system? Why the fan randomly made this "joke" and didn't start?
    Thermostat is new, and so is temp bulb.
    Last edited by resunoiz; 06-13-2012 at 06:17 AM.

  2. #2
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    The electric auxiliary fan should come on low speed when (1) the air conditioner is on, or (2) when the temperature switch on the side of the radiator reaches 91C. The fan should come on high speed when the temperature switch reaches 96C. (These temperatures are the best I recall, some time ago I replaced my temperature switch with a 80/88C switch).

    The temperature gauge on your instrument cluster does not indicate the actual temperature of the engine. It indicates what the computer thinks you need to know (cold, normal, and hot). It's more like a light bulb than a gauge. It should be just about in the center for normal operation.

    From what you describe, I think your car is perfectly normal. You probably had a thermostat that was stuck open for so long that you didn't realize that you were actually running too cold. Now you're running at the normal temperature.

  3. #3
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Sorry, but I have to contraddict you..
    I know that temp cluster is not indicating the "real" temp, but yesterday it went on the 3rd line (3/4 of the indicator). never arrived here before.

    And the very big problem is that in that case, using an electric wire to "simulate" thermostat reaching 90°, the fan didn't started.
    As I (badly) explained on first post, it seemed to start, but for 1-2 seconds, like having an electric impulse, but not continue.
    With the AC on, same issue: the vent didn't move.

    This morning I went to bmw, and made some tests: vent goes fine at every speed instead. There is something that randomly doesnt make start the fan, but I don't know if is a fan problem, a wiring problem or...I don't know.

    Thermostat and temp bulb on radiator are new.
    Last edited by resunoiz; 05-21-2012 at 09:24 AM.

  4. #4
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    I understand more now.

    It seems you have an intermittent failure, which is hard to diagnose. The components downstream from the temperature switch are (1) two relays (1 pink, 1 yellow), (2) a big resistor in front of the fan that gets used for low-speed only, (3) the fan motor, and (4) a lot of wires. Any of these could be failing.
    There is a good diagram of the underhood relay box here:
    http://www.bmwe36blog.com/2008/02/12...-relay-layout/

    You can easily test the fan with some jumper wires and a battery, but you indicate that your fan does operate in some conditions. I would consider replacing one or both relays.

  5. #5
    Join Date
    Feb 2012
    Location
    Florence Arizona
    Posts
    149
    My Cars
    '97 Z3 2.8
    my guess is with blacklane on this. sounds like a relay.

  6. #6
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Infact, even if relays seems to operate, I'll change all two of them wednesday. I'm starting with the cheaper parts

    I was'nt able to identify the big resistor in front of the fan that you describe..i read here about this, but I don't know where it is (my engine is M44). In bmw couldn't help me with this: they say that for E39 was a well known problem with resistor, but for my fan they don't know nothing about it (and there is no spare parts..only the entire fan...sob)

    I searched the forum (honestly on variuos forums.. I'm Italian, and founder member of an official BMW club ) but probably due to my bad english and of technical terms, my searching was unsuccessful, is there any image/guide to find it?


    And about wires...it scares me a lot. there are tons of wires, and connections I honestly have never seen...

    Maybe is useful for the diagnose, I noticed the failure happened 2 times, after a continuative and intensive use of the car (something like 50km higway and then 30km of hi-speed routes), and so I imagine the "heating" of engine and engine compartment may be relevant.
    FOr example, if i turn on the car in late morning and I wait for the fan to operate, it starts regularly. And this is the fact why in bmw is very very hard to discover this strange issue...
    Last edited by resunoiz; 05-22-2012 at 04:00 AM.

  7. #7
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    I didn’t have a camera with me, but I looked at my old fan in my junk pile (my old fan motor would not work). The fan plug has three wires: brown, blue, and black. The brown wire is common and goes to the fan motor. The blue wire also goes straight to the fan motor. The black wire goes to the resistor. The other side of the resistor is also a black wire and is spliced to the blue wire. The resistor is mounted between the fan and the radiator near the fan plug.
    So, if you want to test the fan and resistor, just apply power between brown and black wires on the fan plug. You already know the fan motor works, so there is no need to test between the brown and blue wires.
    The resistor is part of the fan assembly, so it does not have a BMW part number, but equivalent resistors are readily available from electrical and electronic suppliers. The part is something like 0.5 ohms at 80w. I also think you can use the aux fan resistor from older BMW models. Try a Google search for “BMW Aux Fan Resistor.”

  8. #8
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    wow, thanks. And what "does" this resistor?
    reading you I think it "controls" the first speed, or influences the second too?

    and, other question: this resistor may be the same than E39?

    PS: to avoid mistake: I have a SINGLE fan with two speed, between radiator and engine.
    the auxiliary fan is that one, or the one between radiator and bumper (that I don't have)?
    Last edited by resunoiz; 05-22-2012 at 11:29 AM. Reason: Automerged Doublepost

  9. #9
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    The Aux fan is the electric fan between the bumper and radiator. It has two speeds. The high speed circuit is the blue wire to the motor. The low speed circuit is the black wire through the resistor to the motor. In the low-speed mode, the low-speed relay ensures that the high-speed circuit is disabled in the low-speed mode. Otherwise, there would just be a short circuit around the resistor through the blue wire.

    The resistor from an E-39 will probably work. If the resistance is off a few tenths of an ohm, it will only affect the fan speed of the low-speed mode. There are a few BMW designs that have two resistors in series, one at 0.5 ohms and one at 0.3 ohms.

  10. #10
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    ugh...my issue is with the OTHER fan. the Aux fan you describe isn't installed on my car.

    the vent I have installed is between the radiator and the engine.. electric too, but I think is different

  11. #11
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    another question blacklane, you have a viscostatic vent between radiator and engine?

  12. #12
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    Z3s come with an engine-driven fan with a viscous clutch between the engine and radiator. It is mounted to the water pump shaft. Plus they have an electric auxiliary fan between the radiator and front bumper.

    Many people remove the engine-driven fan to (1) allow the engine to speed up quicker, (2) eliminate some failure-prone components (the plastic fan and viscous clutch), (3) reduce some stress on the water pump bearings, and (4) to gain a small amount of power.

    Most people who remove the engine-driven fan replace it with an electric fan mounted to the radiator. If you have an electric fan there, it is an after-market modification. It will have its own set of wires, fuse, and relay. It is probably wired to the battery connector under the hood. It may have its own temperature sensor somewhere, or it may be wired to the BMW temperature sensor on the side of the radiator. SPAL is a common brand to use. Parts should be easy for you to find, since SPAL is an Italian company.

  13. #13
    Join Date
    Feb 2012
    Location
    UK
    Posts
    1,848
    My Cars
    1998 Z3 1.9 5 speed
    Quote Originally Posted by Blacklane View Post
    Z3s come with an engine-driven fan with a viscous clutch between the engine and radiator. It is mounted to the water pump shaft. Plus they have an electric auxiliary fan between the radiator and front bumper.

    Many people remove the engine-driven fan to (1) allow the engine to speed up quicker, (2) eliminate some failure-prone components (the plastic fan and viscous clutch), (3) reduce some stress on the water pump bearings, and (4) to gain a small amount of power.

    Most people who remove the engine-driven fan replace it with an electric fan mounted to the radiator. If you have an electric fan there, it is an after-market modification. It will have its own set of wires, fuse, and relay. It is probably wired to the battery connector under the hood. It may have its own temperature sensor somewhere, or it may be wired to the BMW temperature sensor on the side of the radiator. SPAL is a common brand to use. Parts should be easy for you to find, since SPAL is an Italian company.

    That's not actually 100% accurate. There is an option of a suction fan that mounts between the radiator and the engine. Have a look at:

    http://www.realoem.com/bmw/showparts...62&hg=64&fg=55

    I have this on my M44 as well (No viscous). It's controlled by the double temperature switch.

    I actually have a small issue with mine, but I'll start another thread about that.

  14. #14
    Join Date
    Jun 2011
    Location
    Springfield, Ohio, USA
    Posts
    1,233
    My Cars
    1998 Z3 Roadster
    Thanks Bladerunner919. I had never seen one of those. Do you think you can help Resunoiz diagnose his problem?

  15. #15
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Quote Originally Posted by BladeRunner919 View Post
    That's not actually 100% accurate. There is an option of a suction fan that mounts between the radiator and the engine. Have a look at:

    http://www.realoem.com/bmw/showparts...62&hg=64&fg=55

    I have this on my M44 as well (No viscous). It's controlled by the double temperature switch.

    I actually have a small issue with mine, but I'll start another thread about that.
    so you have same configuration as mine.
    I read your thread
    http://forums.bimmerforums.com/forum....php?t=1845266
    is EXACTLY my same issue (explained better...)

    Thermostat is new, and so relays. When I jumper on the connector between pin n.1 and n.2 it starts regularly as yours, but when I plug the connector on the thermostat, nothing about the lower speed. I wonder if is a DME issue. Or maybe the contact is closed, but with nont much resistance...
    a connector issue (but it seems okay)or...what?
    Last edited by resunoiz; 06-07-2012 at 08:15 AM.

  16. #16
    Join Date
    Feb 2012
    Location
    UK
    Posts
    1,848
    My Cars
    1998 Z3 1.9 5 speed
    Quote Originally Posted by resunoiz

    Thermostat is new, and so relays. When I jumper on the connector between pin n.1 and n.2 it starts regularly as yours, but when I plug the connector on the thermostat, nothing about the lower speed. I wonder if is a DME issue. Or maybe the contact is closed, but with nont much resistance...
    a connector issue (but it seems okay)or...what?
    So yours does run when you jumper the pins? I had the impression from your posts that the fan was only running for a second or two, even with the aircon button on?

    Mine runs continuously at low speed with the with the aircon on, will run at low or high depending on how I jumper the connector to the temperature switch, and will run on high when the engine gets hot, but never runs on low speed due to engine temperature. Is that exactly what you're experiencing?

  17. #17
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Quote Originally Posted by BladeRunner919 View Post
    So yours does run when you jumper the pins? I had the impression from your posts that the fan was only running for a second or two, even with the aircon button on?

    Mine runs continuously at low speed with the with the aircon on, will run at low or high depending on how I jumper the connector to the temperature switch, and will run on high when the engine gets hot, but never runs on low speed due to engine temperature. Is that exactly what you're experiencing?

    T H E S A M E.
    sob...I can't go out of this trouble...

    but maybe you can do a test, to verify there are no wiring issue..

    I read you are experienced using wires: yu changed the connector and so on. So you could try to exchange pin n.2 and n. 3 and see if vent goes. in that case is not a thermostat issue I think...
    Last edited by resunoiz; 06-07-2012 at 09:36 AM.

  18. #18
    Join Date
    Feb 2012
    Location
    UK
    Posts
    1,848
    My Cars
    1998 Z3 1.9 5 speed
    Quote Originally Posted by resunoiz
    T H E S A M E.
    sob...I can't go out of this trouble...

    but maybe you can do a test, to verify there are no wiring issue..

    I read you are experienced using wires: yu changed the connector and so on. So you could try to exchange pin n.2 and n. 3 and see if vent goes. in that case is not a thermostat issue I think...
    I'm going to have another go at it at the weekend, so I'll keep you posted!!

  19. #19
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Quote Originally Posted by BladeRunner919 View Post
    I'm going to have another go at it at the weekend, so I'll keep you posted!!
    I'll be very, very tuned

    Quote Originally Posted by BladeRunner919 View Post
    I'm going to have another go at it at the weekend, so I'll keep you posted!!
    maybe you can do another test: put 3 little wires on the temp switch and see with tester if pin n° 1 and 2 have voltage when the engine starts heating (before the higher speed starts, so you're sure the lower heating contact is reached)
    Last edited by resunoiz; 06-08-2012 at 04:43 AM. Reason: Automerged Doublepost

  20. #20
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    SOLVED!!!!
    the guys on my italian club (bmwdrivers.it) solved the mystery!!!

    M44 motor had, at that time a DIFFERENT thermostat than 318 is. different codes, same bulbe.
    BUT now that different code in bmw provides the SAME thermostat. Myabe at that time, the cars made without thermostatic had this modifications not well explained on the mechanic manuals..I don't know. But WDS speaks clearly.

    seeing the wirings, we noticed that for the same schemathics, in Z3 and 318is the pin n.1 and 3 have INVERTED positions (due to a poor representation, i think, the thing isn't so evident). M44 on Z3 changed to the one like 318is on 03/1997, but ETK is not so accurate..mine is 08/97 and mounts the unmodified one.
    The spare part you can now buy is the one for 318is, NOT for z3 with same engine.
    here the schematics on the connector of the thermostat for 318is M44.


    But the thermostat would have pin with mas and vel2 INVERTED (will be correct for 318is) , se WDS for details... for z3 1.9 the wiring of the connector results wrong. When the first speed have to start, thermostat opens NOT mass and vel 1, BUT vel1 and vel2, resulting in a tension between the 2 relays (and no vent start): if you measure on the fuse box, instead of having a +12 when the firs speed have to start, you'll have a suspect 0v. When the contacts is off, you have a more strange 7,9v.....

    So I disconnected the plug, opened it and interchanged the pins named MASS and VEL2.

    The vent now starts at lower and higher speeds regularly!!

    The first speed now has the right tension and starts, and the second one functions properly as ever done (infact the connections of that second speed remains the same).

    Bladerunner, if the thermostat of your car is OK, you have to do this little test!
    Last edited by resunoiz; 06-13-2012 at 05:57 AM.

  21. #21
    Join Date
    Feb 2012
    Location
    UK
    Posts
    1,848
    My Cars
    1998 Z3 1.9 5 speed
    Well done. Unfortunately mine is wired correctly already, so I'll have to keep looking!

  22. #22
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Quote Originally Posted by BladeRunner919 View Post
    Well done. Unfortunately mine is wired correctly already, so I'll have to keep looking!
    are you sure? mine was too. for the schematics there's nothing wrong. and jumpering in the connector, everithing works correctly.

    is the NEW bulb production (the spare parts you've changed some times ago as you said) that doesn't fit original standard but was wrongly mistaken by BMW for the 318M44 type that has pin 1 and 3 inverted (they will be okay for 318is M44).

    make a try: remove lo-speed relay, and measure tension at pin n. 86b with thermostat connected, waiting for the highest speed to start ( that means waiting the lo-speed contacts on the thermostat close due to reaching 80°, till it closes at 85°) then jumper the wires on the thermostat connectors to simulate the first speed to start, and measure again.
    you will have "suspect" values. instead of a 0 in open contact and +12 on closed contact, the 86b pin will give you strange (approx 7-8v) value. because the "new" thermostat in this moment is connecting NOT mass and 1st speed, but hi-speed and lo-speed relay.
    excnanging pin and 3 on thermostat conenctions recreates the right contacts for this "inverted" new thermostat. and don't be afraid, you cant broke nothing. 2nd speed will start in any case (that speed contact remains inalterate, you only invert its wires on the right connection for 2nd speed).

    The problem is NOT on wires and bad assembly, but in the thermostat that doesn't meet the original specs.
    I read that you car is 1998, and a different code thermostat was specified for 96-97 cars. maybe you have a "transition" model one. (will not be the first time..mine, for that case, is)
    what sn has your thermostat? REAL OEM is not accurate in this too. there were two thermostat
    61318361787 (96-till 03/97 )
    61318376440 (from 03/97)

    the first one is no more available, the code points at 61318376440.
    and, in addiction, my car is 08/97. that confirms the non-accuracy of that codes (theorically, I have the 61318376440, that instead does not fit my wiring as explained)


    I know my bad english won't help you a lot undertanding, but is a to-do trying :P
    Last edited by resunoiz; 06-11-2012 at 03:47 AM.

  23. #23
    Join Date
    Feb 2012
    Location
    UK
    Posts
    1,848
    My Cars
    1998 Z3 1.9 5 speed
    Both my old and new switch are 61318376440. I took the old one apart and my wiring is definitely set up as per that switch.

  24. #24
    Join Date
    Mar 2005
    Location
    italy
    Posts
    288
    My Cars
    Z3 M44 roadster 1997
    Quote Originally Posted by BladeRunner919 View Post
    Both my old and new switch are 61318376440. I took the old one apart and my wiring is definitely set up as per that switch.
    make a try requires 2 min (included car warming )
    my old switch (i thought was broken) was 61318376440 too. was simply the wrong spare part (but RIGHT for realoem).

    Maybe it NEVER had run at first speed and you've never noticed it. I noticed it only for a coincidence
    Last edited by resunoiz; 06-11-2012 at 09:13 AM.

  25. #25
    Join Date
    May 2014
    Location
    Madrid, SPAIN
    Posts
    9
    My Cars
    BMW 318ti
    Hi, My name is Victor and i have a BMW 318ti 1998.

    I wanted to know if you it turns on the fan much. When i stopped more than 30 seconds, the fan switch on and works over the minute.

    This is Normal?

    Sorry for my english, but i am Spanish.

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •