E46 Fanatics Forum banner

330Ci radiator fan acting up

Tags
fan radiator
12K views 36 replies 7 participants last post by  IxNay 
#1 ·
Hi everyone, first post to the forum. I've been lurking for the last few weeks since I bought my first car, an '04 330Ci (and have been trying to fix its problems :cry:)

Anyway, I'm having a strange issue with my radiator fan. The first time I had an issue with it was when the car was idling in my garage after a short drive, and the temp needle was creeping up to the 3/4 mark, which at this point I decided to turn the car off.

I thought it might be the control unit on the fan itself, so I swapped it with a spare one I had that (I think) worked. Tried it again but this time I monitored the temp with the OBC test display (test 7). The temp slowly raised up until 115 degrees until I shut off the car. The fan did not turn on at any point UNLESS I turned on the AC. If I turn on AC, the fan turns on, but it seems like its spinning slowly, and it didn't help the coolant temp go down. Because it's reading the temperature okay, I don't think its the lower radiator hose temp sensor. I tested for any OBD codes but the car was not reporting any. Also checked fuse #37, for the electric fan, but that was fine as well. I am about to check if the fan is getting a PWM signal and proper power.

Anyone have any ideas on what is happening and how to fix it? I'm really stumped on this. :banghead:
 
See less See more
#2 ·
Update: tested to see if the fan turns on for 20 seconds when I start the car. It doesn't.
 
#4 ·
Thanks, I saw that earlier today.

Another update, tested for PWM when I started the car (20 second diagnostic test) and I got a small signal, but not much. The fan still didn't turn. It seemed less than 20%. I turned on AC but the PWM signal stayed the same?? :hmm:
 
#5 · (Edited)
Unplug the lower rad hose coolant temp sensor (CTS) then start the car. After 30 secs turn AC =ON within another 30 secs the fan should default to high speed - as a failsafe. This tells you that the fan motor is OK and the power connections are also good. You may still have issue with the PWM signal wire or the CTS. If the fan is not on high speed shut off before you cause an overheat.

If the lower rad CTS is giving off bad values (below actual) this could cause an issue in calculating the final output from DME (your PWM signal) if the CTS is giving off "implausible values" (I.e. -470 etc) then after 2 of these values it is also supposed to default to high speed.

Your fan module may be ok - start with the temp sensor. Most often cause of fan failure is corrosion of the fan module terminals and probably the CTS second. Check to see if the silicon sealer is cracked and the connections have gone green (on both sides of the module)

Your profile didn't mention your location. If you are in a snow region I'd bet it is corrosion of the terminals.
 
#8 ·
Unplug the lower rad hose coolant temp sensor (CTS) then start the car. After 30 secs turn AC =ON within another 30 secs the fan should default to high speed - as a failsafe. This tells you that the fan motor is OK and the power connections are also good.

If the lower rad CTS is giving off bad values (below actual) this could cause an issue in calculating the final output from DME (your PWM signal) if the CTS is giving off "implausible values" (I.e. -470 etc) then after 2 of these values it is also supposed to default to high speed.
Thanks, BMW-North. I swapped back to my original fan because I had doubts if it had actually failed. I then ran the test you suggested, and the fan did default to the fail safe and ran at high speed. Does this mean my lower radiator hose temp sensor is bad?

3ric15, you picked a fine car for your first one! The E46 is a terrific car and will serve you well as long as you keep your eyes, ears and nose tuned in for any signs of impending issues. You did well to notice your car was about to overheat because you saw the temp guage rise and you shut it down before you cooked your engine. The same exact sympoms just started to happen on my car and I will be doing the tests suggested by BMW North. His pdf write up on the radiator fan is great. Like you I saw the temp needle go up on my car and I shut it down right away. Good luck with your new car :thumbsup:
Thanks! My friend has an automatic (auto-tragic IMO) 330Ci convertible and I really like the way it looks, and they're not too expensive as a used car, considering what you get out of it. My car has the sport, premium, and cold weather package along with the 6 speed manual. It's the fastest car in my family's driveway right now. :woot: I guess I should probably do this on the introductions thread, but oh well. My dad and I have been racing in SCCA RallyCross for the last few years since I started driving. We drove an old 325e e30 (and beat the piss out of it, has >400k miles, etc). We have been working for the last two weeks trying to get a 'new' car, a 325i e30, prepped with go-fast suspension bits and all that for tomorrow's race.
 
#6 ·
3ric15, you picked a fine car for your first one! The E46 is a terrific car and will serve you well as long as you keep your eyes, ears and nose tuned in for any signs of impending issues. You did well to notice your car was about to overheat because you saw the temp guage rise and you shut it down before you cooked your engine. The same exact sympoms just started to happen on my car and I will be doing the tests suggested by BMW North. His pdf write up on the radiator fan is great. Like you I saw the temp needle go up on my car and I shut it down right away. Good luck with your new car :thumbsup:
 
#7 ·
Both of you should think about the Temp Gauge Buffer Adjustment DIY - well documented on here. I think e46 fanatics learn to drive with one eye on the road and the other on the temp gauge - the buffer DIY just gives you an earlier warning. OBD Fusion and a wifi OBD dongle with my iPhone showing a dashboard with the e46 engine temp is how I drive one these days.

Good luck to both of you. If you need anything just PM.
 
#13 · (Edited)
It would appear that your fan assembly is not working.

As I mentioned earlier without INPA it is process of elimination trying to diagnose the fan module. I would suspect your fan module is shot. I'm assuming you've checked that fuse 37 is ok? and that there is 12v to the two thick wires at the connector (pigtail) - constant power 24/7 - even with no key in ignition. If it is a manual fan - it's a 5 minute removal then you can put 12v using leads direct to the fan motor terminals to satisfy your curiosity that the fan motor perhaps still works direct to power. - as I said typically the module craps out - especially in NE States and Canada where salt is used on the roads.

Edit - Given the age of your 328 I'm curious as to whether you have the Bosch Gen 1 or the Siemens integrated fan. BMW had a recall on the Siemens which I know as late as 2011 they were still publishing in it in their releases - If you don;t have a fan module bolted on the shroud it will be a Siemens.

In either case - if this is the OE fan - you got 16 years out of it in a harsh climate - pretty good.
 
#17 · (Edited)
Ok so I replaced the lower radiator hose temp sensor anndddddd.... fan still not turning on :ben: I added a lot of coolant as well and that helped slow the rate the temp was raising, but I'm still having this fan issue. OBC display reported 92 degrees before I shut the car off. My dad used an IR thermometer to measure the hose temps. The upper hose that has the bleeder seemed to be getting up to temperature (~70-ish degrees) but the lower radiator hose was close to room temperature (25 degrees). Does this mean my thermostat is not working correctly because coolant is not flowing through the radiator? And does the thermostat being open have anything to do with the DME sending the correct PWM to the fan?

Edit: forgot to mention that I had the interior HVAC set to max temp at low fan speed, as well as the 'wheel' next to the dashboard vent set to the 3 red dots (I was bleeding coolant). I thought it was a little interesting how that even with the coolant temp getting pretty hot the air coming out of the vents stayed cool. I am curious as to whether this is related to how the cooling system is designed or if it is a separate issue.
 
#20 · (Edited)
I don't think it is the fan, because it defaults to high speed if I unplug the sensor. It could still be a problem I suppose.

The thermostat could have failed in the closed position. 92*C is low as these cars run in the 95*-100*C range.
That is what I am thinking. The lower radiator hose isn't getting anywhere near up to temp.

Edit: looking at new OE thermostats they all say 206* F which is ~96* C. I only got up to 92. I'll bleed the system again then test it going above 96* to see if it opens when I get home from work.
 
#21 · (Edited)
If you're not getting up to normal op temp (which will be the value stamped on your t-stat as normal temp can vary by region and designation) I would suspect that your t-stat failed OPEN (which is what it is meant to do BTW when it fails)

The tests I have suggested for you to diagnose will only be helpful if everything else is working (including circulation, T-Stat, WP, CTS etc). Really the INPA Fan Test is the only guaranteed test for the Aux Fan Module but if you know everything else functions properly you can typically pinpoint the fan module thru process of elimination. Your fan won't spin in the high range at 92C - but it shouldn't overheat at that temp either??

It could still be the fan even though the fan defaults to high speed. The way this system is designed the fan switches to high speed on an input failure (CTS) - it therefore bypasses the PWM signal and the full voltage is sent to the fan motor. If your PWM signal is not functioning or being interpreted properly at the fan module then your fan won't spin on some or all 15 speed requests. I have noted that most often the high speed ranges are the first to stop working.
 
#22 ·
Good news and bad news... Good news is my fan turned on and thermometer showing ~60* on lower radiator hose when the OBD showed 98*, which means coolant is flowing, and the temp sensor is working properly (with AC off of course). Bad news is my expansion tank is leaking when the engine is up to temp, which explains why it took sooo much coolant when I filled it up last night, and perhaps why it was overheating in the first place. But at least I know what the problem is. Any recommendations as to which tank I should get? I read somewhere that some aftermarket ones have the leaking issue fixed.
 
#29 ·
I'm super stoked right now :craig: I changed the expansion tank and flushed the coolant system, and put some new coolant in. Went on a test drive and temps were ok! never hit above 98* and that was sitting still (and yes the fan was on this time :p). I am going to do another round of bleeding tomorrow morning after the engine cools down.

As for the car, it feels great and pulls hard! Thanks everyone for your help.
 
#36 ·
I just got my scanner yesterday, so that is something I will also do today.
 
#31 ·
Hi every one i have e46 2000 328i auto tanss .i want to delet my mechanic fan clutch and replace it with one electric fan and the only way to connect the electric fan is to use the front electric fan connector. but the comnector only workes when the AC is on dose it means i have to keep the AC on all the time while driving to keep the fan running???
 
#32 · (Edited)
No. Means you have other cooling issues.

By the way you already have an electric fan. So you're just deleting a fan. The mechanical fan that's been cooling your engine presently while your electric fan isn't working properly.

There is plenty of info in other threads about deleting the fan but you're in a hot climate. Last thing I'd want to be doing is reducing the cooling capacity of an aging car and replacing the oe components with known quality issue aftermarket Chinese parts. I'll post a link shortly. You likely need a cooling temp sensor or a new fan module.
 
#33 ·
Didnt really understand you bmw-north .if i delet the mechanic fan and the aux fan replacing both fan with only one electric fan on the radiator i think that is possible but the problem is that if i connect the electric fan to the aux connector the fan will not run on till i put on the AC .that means if i am not using the AC i will not be having the electric fan running
 
#34 · (Edited)
What you are doing is well documented in this thread:

http://forum.e46fanatics.com/showthread.php?t=849735


However - please read my comments on or about here:

http://forum.e46fanatics.com/showthread.php?t=849735&page=38

To answer your question - the electric fan in any circumstance is turned on to cool the engine - not only when AC is running. If your car will only turn on the electric fan when AC=ON then you have another problem similar to the original poster in this thread. Simply swapping your current pusher fan for a puller fan might not fix the issue (if it is say the coolant temp sensor for example) then, you would not have the benefit of the viscous clutch fan (mechanical fan) to save your engine from overheat since the electric fan might not be operating when it should.

Notes for the Fan Delete Mod
Edit: to answer a question I noted in another thread that asked. When you delete the mechanical fan how does the DME know now just to use the single electric fan for cooling? - Answer: It doesn't, the e46 uses cooling mapping which has setpoints. In simple terms the DME has a table of values that are thresholds for activating requests. The goal is to maintain a desired temperature within a small range. Since you have less cooling without the mechanical fan the DME senses the increased temps through sensors and signals the electric fan to operate more often and at higher speed requests - in other words the DME is now driving the electric fan harder and more frequently to maintain the desired temp ranges that are set in it's logic. This is not equal to the condition on a manual transmission e46 configuration since cooling requirements for these vehicles is lower so the fan operates in the high ranges less often. It is therefore more important for vehicles having removed the mechanical fan that the electric fan be 100% operational.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top