Help!! What could this mean?

[JimLev]

wrong with the fan, the resistors, the relays, or the fuses.
Steve you said it ran for 15 min yesterday and the fan never came on, possibly the outside temp wasn't hot enough and the clutch fan was doing it's job keeping everything cool. I'm in MA, wasn't really warm here yesterday, maybe 60 F tops.
When the AC is switched on the aux fan should come on. Look at the schematic in my post above, it shows that the fan should be running on the low speed when the AC is switched on. The other speeds are controlled by the temp sensor on the side of the radiator and the pressure sensor in the AC loop.
What's the last 7 of your VIN? just want to verify that the above schematic is the correct one for your model year.

[JimLev]

the system to stay in the center when the temp is between 75C to about 125C.
Possibly some of the other aux fan speeds were working this last summer and they are now not working.
Your fan should switch on when the AC is turned on. See my other post below.

[JimLev]

the Aux fan speed circuit, yours could be bad if the fan doesn't run when the AC is turned on.

http://bimmer.roadfly.com/bmw/forums/e39/9510618-1.html

[gitchman72]

and seeing that schematic you posted Im thinking there is defanitly a problem with the speeds. Why I think that is, I have only heard this fan kick-on during the hot summer months and only on high. You can hear the dam thing 20ft away it's so loud. Im in NY so the temp been in the low 60's during the day & upper 40's to low 50's at night, thank god. I am not near the car right now actually at work, I will get you those VIN numbers a little later. I really thank you for all the help so far, this site is great and you have been great with information. Thank you again!

[Jim Cash]

Are you "sure" it is the Aux (electric) fan you hear coming on? Your description makes it sound more like the main fan speeding up due to the heating of the fan clutch (this is by design) and this is the fan that does sound loud on the occasions when it does wind up.

Make sure your Aux fan is working before going further - and NEVER drive the car when the temp gauge is above normal - an overheat can destroy an engine very quickly.

After the aux fan is operating correctly then concentrate on the thermostat and "proper" bleeding of the system.

Cheers
Jim Cash

[gitchman72]

to you earlier, work has been nuts.. Anyhow here is the info on my VIN BW47809. The temps have been cool here in NY so no need for air, the car has been running normal< i know I need to get this fixed. That is a job and a half to get at that fan, no wonder is so expensive to work on these cars they don't make it easy.




Steve

[JimLev]

Just wanted to make sure the prints above matched your car. They do.

#6 is the temp switch you can jump out to see if the fan will run

#8 is the resistor kit that hopefully is the only thing wrong with your aux fan not working
Hi speed will still function with both resistors burned out, they are in the low and medium speed circuits.

[JimLev]

pull the connector off the temp switch and ground the black/gray wire (pin 1) that will pull in relay K201 in the DME box and make the aux fan run at high speed. This is providing the relay and fuses are good.
Grounding the black/red wire will turn on the low speed, this is the same thing that the HVAC panel does when you turn on the AC. You have said this doesn't work, hopefully it is just the resistors.
The ignition key has to be in the run position for the above tests.

[gitchman72]

Well I know I have one isssue with the aux fan cause it don't come on when the AC is is turned on. In NYC where it has been really cold temps in the 50's during the day low 30's - upper 40's at night,so havn't turned on the AC.

So I leave work tonight and im driving home about 10 min into the ride the temp gauge starts to climb,now mind you I am moving on the highway about 40 miles and hour and and the outside temp is 44.

I start to speed up more and in about 20 seconds the temp goes back to the middle. The whole time I was moving, never stuck in traffic. When I get home I let the car run for 20 min in front of my house to see if it does it again... nothing.

I had the the hood open to see if at any point the AUX fan came on to cool it down if it sense it was getting too hot and nothing. So looks like I have another problem besides the AUX fan. What is causing this temp gauge to rise?

Sitting running for 20 min and no issues driving on the highway at 40 miles an hour with cold temp outside and it goes up? Waterpump? thrmostat? Air in the system? This is killing me...

Thanks!
Steve

[Filehorse]

I was experiencing similar issues a few years ago while my E39 was still under warranty. Only difference was my temperature would mysteriously drop below the mid-point for no apparent reason. Turns out it was the thermostat sticking in the open position. Simple replacement solved my problem. Since the thermostat is a key component controlling coolant temperature, I'd have to look there first - especially since it's a relatively cheap fix compared to some of the other possibilities. If you thermostat is original equipment, I'd definitely be looking at it closely since failure is not an uncommon occurrence in these cars. When you hear hoof beats, consider that it just might horses instead of of zebras.

Let us know what you find.


Filehorse
Knoxville, TN
BMWCCA #407627

2002 525i Steptronic Sport/Premium | Build Date: 05/02
81,000 Ultimate Driving miles
Xenons
Style 81s | Bridgestone Potenza RE960 AS
Titanium Gray | Gray Leather
35% LLumar ATR LLumaStar tint
Valentine 1 | Hardwired
Steering wheel position memory w/Alzheimers
"Lifetime" ATF replaced at 40,000; Switched to Valvoline MaxLife @ the 80,000 mile service
StopTech SportStop slotted rotors w/Axxis Deluxe Advanced pads
StopTech SS Braided Brake Lines

2001 E46 325i (Jet Black) Forced Retirement 6/28/09

2001 E46 325i (Orient Blue) Forced Retirement 10/09

1989 E30 325i (Alpine White) Retired

[JimLev]

the aux fan problem soon. Filehorse is probably correct on the t-stat, when you first start the car the t-stat is closed, it is probably sticking which will cause the exact problem you have.
If you could look at the OBD temp display you would see that the engine coolant temp does rise above the correct operating temp just before the t-stat begins to fully open and then drops back as the colder coolant from the radiator begins to circulate.
Your lucky the t-stat did open, otherwise you would have warped the cylinder head.
Your driveway test with the hood open (no load on the engine and heat escaping from open hood) won't tell you much.
Did you ever jump the pins that I told you to determine if your fan or the resistors were bad?
When was the last time your coolant was replaced? It has lubricants in it as well as corrosion inhibitors to help maintain parts like water pumps and t-stats.
Did you have heat from the cabin heater the whole time?
Coolant level OK in the AM when the engine is cold?

[JimCash]

You say this is "killing" you - but actually since you are still driving it in an overheat condition you may be killing the engine. In fact you may have already caused damage that is giving you the overheat issue.

I strongly suggest you get this to a professional NOW - and a person that knows BMW coolant systems and the proper way to test and bleed them.

All the following things have to be checked
- thermostat operation
- main fan operation (clutch)
- Aux fan operation (all speeds)
- water pump flow
- rad flow (internal restriction?)
- air flow across the rad (debris in and around the rads)
- coolant condition and level
- system bleeding (done properly in the dual stage method to make sure the heater system is free of air)
- system pressure tested (cold and hot). Some "iffy" hose connections will only sow a leak when the system is under hot pressure.

Also it is now a good idea to have the coolant and oil checked for possible cross contamination due to an internal engine leak.

Cheers
Jim Cash

[gitchman72]

Ok, Thanks!

[gitchman72]

Ok, I never jump the pins,not good at that stuff. Tryin to find a good repair shop, don't want to go to the dealer because they are way too much. My repair guy is not good, oil change ok anything elese stay away. Sad part is all they work on is foreign cars.


The time I had the air in the system, they could not determin what was wrong, wanted to changed the rad. Went to the dealer (had a friend working there at the time) and they told me it was air in the system.

In in NYC "Brooklyn" to be exact tryin to find a good shop.. I been told about Bay Diagnostic in brooklyn but I have gotten mixed reviews.

Ahhh this sucks.............


steve

[Vin M]

and I've never had a problem with their work.

You need to get it to someone, I don't know any other places (that I personally have experience with) to recommend to you in the Brooklyn area, and if you take the car someplace further away, the tow charges will likely drive your final cost up as much as if you took it to the dealer anyway.

I must reiterate what both Jim's said...it's imperative that you don't drive the car anymore until this issue is resolved, my friends 528i met with an early demise because of the same type of issue (he kept driving it while overheating), these engines are super-sensitive to overheating damage.

Btw, his thermostat turned out to be the culprit...so basically, he sacrificed an engine for a thermostat...don't let this happen to you!

Vin

[gitchman72]

[gitchman72]

I opened the rad cap when the car was cold, should it be full? Mine was not. I believe there is a line which says cold about a 1/4 of the way down the plastic see through container.

[JimCash]

That line is where the level should be when "cold"

NEVER FILL the unit - you need that trapped air above the top of the coolant to allow for expansion in the system.

This is a "sealed" system with an expansion tank - not like those that have an overflow/recovery tank that is exposed to atmospheric pressure.

Cheers
Jim Cash