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Discussion Starter · #1 · (Edited)
Hello, I have a question about the needle position of the water temp gauge at the right side of the instrument cluster.
I remember it used to point 12 o'clock once warmed up.

It has started to incline more and more to the left side for about two years and now the warmed up position is at just right side of the left dot.

I checked with the manual in the FAQ of this forum and it told me it is OK if the needle is between the two dots.
I also did the same with my own car's manual (in Japanese) and it says it is OK if it is between blue and red zones(why the difference?).

The T-stat and the temp sensor were replaced about a year ago and it did not improve the problem.

Is it repairable? Or do I have to replace whole instrument cluster? Any comments are welcome.
(Attached is an INPA result showing water temps.)
 

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You can change its position. The cluster can be calibrated. Read through this thread I believe the answer is secondary in one of the descriptions. It is not easy but only requires the correct software and a delicate touch. The gauge is not accurate and different on many cars. I am at 80 c just right of the dot but at 82 I am past center.
 

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Discussion Starter · #3 ·
You can change its position. The cluster can be calibrated. Read through this thread I believe the answer is secondary in one of the descriptions. It is not easy but only requires the correct software and a delicate touch. The gauge is not accurate and different on many cars. I am at 80 c just right of the dot but at 82 I am past center.
Hi, Sailor24, thank you for your quick reply:smile.
Grad to know it can be calibrated but I am wondering which thread I should read and what software I need.
 

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Hi, Sailor24, thank you for your quick reply:smile.
Grad to know it can be calibrated but I am wondering which thread I should read and what software I need.
If you want to verify temps, unlock the On Board Computer and go to test 7. It will read out the water temp, test 16 the oil temp.

Regards,
Jerry
 

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Discussion Starter · #6 ·
I have skimmed the thread and found it a bit complicated(and it is secondary). I think I should wait and see a while till the thread starter adds more DIY pics. It may be a fun if I could change clusters freely just as he does.
I was surprised to know the 2004+clusters won't have dead pixels any more. I used to have a brand new E39 530i(2003) and bad pixels appeared only after three years.
 

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Discussion Starter · #7 ·
If you want to verify temps, unlock the On Board Computer and go to test 7. It will read out the water temp, test 16 the oil temp.

Regards,
Jerry
Hello, Jerry,thanks for your reply.
Frankly I am not worried about the sensor so much. Please take a look at the first post. The INPA result shows 79C after the engine was warmed up. Anyway I will do those OBC checks for confirmation.
Usually I drive in city, so the temp seldom goes up.
 

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This is timely, read my fan clutch thread below. Is your fan clutch due for replacement? Never recalibrate anything without knowing the source of the problem. If your engine oil temp gauge is also leaning a little more leftward I wonder if it is the fan clutch stiffening up and providing a little too much cooling. That was my case. While everyone's cluster can be a bit different it is collective experience here when you look at dash photos and read people's descriptions and from your own experience that the temp gauge really should be bolt upright - so something has changed on your car.
 

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I have skimmed the thread and found it a bit complicated(and it is secondary). I think I should wait and see a while till the thread starter adds more DIY pics. It may be a fun if I could change clusters freely just as he does.
I was surprised to know the 2004+clusters won't have dead pixels any more. I used to have a brand new E39 530i(2003) and bad pixels appeared only after three years.
Hey there, I'm the thread starter of that DIY. I will plan on adding some pics at some point, but since we can't edit a post after 24 hours, it will require moderator support for that. Also, I don't think you'll be able to fix your problem with software. Open the hidden menu by holding the right button on the cluster until Test No. 1 comes up. Hit the left button again for Test No. 2, then hit the right button. The needles should sweep their entire range a couple times. If the coolant needle looks like it's getting stuck at some point or doesn't return to the starting position, then you have either a stepper motor problem or the needle is pressed down too far and it's hitting the gauge face (usually if someone has done pixel repair before and accidentally pushed it on the shaft too much). Considering your coolant temp shown in INPA shows 80*C, I'd say that you're at normal operating temperature and that the problem is gauge related.

If you need it fixed PM me.
 
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Discussion Starter · #10 ·
Hey there, I'm the thread starter of that DIY. I will plan on adding some pics at some point, but since we can't edit a post after 24 hours, it will require moderator support for that. Also, I don't think you'll be able to fix your problem with software. Open the hidden menu by holding the right button on the cluster until Test No. 1 comes up. Hit the left button again for Test No. 2, then hit the right button. The needles should sweep their entire range a couple times. If the coolant needle looks like it's getting stuck at some point or doesn't return to the starting position, then you have either a stepper motor problem or the needle is pressed down too far and it's hitting the gauge face (usually if someone has done pixel repair before and accidentally pushed it on the shaft too much). Considering your coolant temp shown in INPA shows 80*C, I'd say that you're at normal operating temperature and that the problem is gauge related.

If you need it fixed PM me.
Thank you so much for this useful info.

Test No. 2 showed the needle swept its range smoothly and returned to the original position and, as you suggested, excluding gauge motor failure.

The INPA result was taken last November. I also did Test No. 7 today to obtain the Ktemp of 75C. (Also Test No. 16 gave the oil temp to be 82C.)
This makes me look at;

1. Fan clutch as CarbonCopy suggested
2.T-stat
3.Temperature sensor

with the latter two less likely because they were replaced last year as stated before.

Thanks again for the info. I am looking forward to seeing your DIY pics.
 

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Discussion Starter · #11 ·
This is timely, read my fan clutch thread below. Is your fan clutch due for replacement? Never recalibrate anything without knowing the source of the problem. If your engine oil temp gauge is also leaning a little more leftward I wonder if it is the fan clutch stiffening up and providing a little too much cooling. That was my case. While everyone's cluster can be a bit different it is collective experience here when you look at dash photos and read people's descriptions and from your own experience that the temp gauge really should be bolt upright - so something has changed on your car.
What a coincidence!
I did Test No. 7 and 16 to get 75C and 82C respectively. Though I do not have the reference value for the oil temp, the water temp of 75C(at idle after three mile drive) seems to be too low.

I will have the fan clutch checked soon.
Actually the INPA result was taken last November and degradation may have proceeded during the period.

Thanks for your very timely reply.
 

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Actually if you get a different reading in inpa and the dash it points to the sensor, or I suppose a very odd flow in the Tstat housing. The temp sender has two elements in it. One for the DME read INPA and one for the dash read test 7. Since it is new I might suggest you look very close at the connector. 68FB had problems there and if I recall it was lower temp readings. I know others have had the same problem. Not sure what the fix was but he may have replaced the whole plug. PM him and ask because I am not clear on the details.
 

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Discussion Starter · #13 ·

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If they spin free they might be shot but that will not over cool the car. These fan clutches are different. Most mechanical fans are primary these are secondary. The electric fan cools the car the mechanical one is back up. It engages at a higher temp than normal so they do spin freer than most. The real test is to get the car hot and see if you can stop the fan with a rolled up newspaper. Then check and make sure it spins free when cool.
 

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If they spin free they might be shot but that will not over cool the car. These fan clutches are different. Most mechanical fans are primary these are secondary. The electric fan cools the car the mechanical one is back up. It engages at a higher temp than normal so they do spin freer than most. The real test is to get the car hot and see if you can stop the fan with a rolled up newspaper. Then check and make sure it spins free when cool.
Make sure when doing the newspaper test that you poke it at the center of the fan and not the blade tips. You risk breaking fan blades otherwise.
 
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Discussion Starter · #16 ·
If they spin free they might be shot but that will not over cool the car. These fan clutches are different. Most mechanical fans are primary these are secondary. The electric fan cools the car the mechanical one is back up. It engages at a higher temp than normal so they do spin freer than most. The real test is to get the car hot and see if you can stop the fan with a rolled up newspaper. Then check and make sure it spins free when cool.
Obviously there are really many things I do not know.
What would be the purpose of the newspaper test? If the rolled newspaper stops the fan, does it mean the clutch is OK?

I remember 68FB mentioned the test in 'Codes causing the SES light' thread but I could not understand his intention at that time.

Is it correct the fan below is what we are talking about?
 

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Personally I would not do the newspaper thing, but it seems to be the popular thing around here. I think all you need to do is unplug the electric fan and drive the car hard to get it hot. Then listen for it to engage, after or before with it cool, see if the fan spins freely. The dangerous failure is when they lock up and don't spin freely. If it never engages you would likely never have a problem unless your aux fan failed. Some have removed them completely.
 

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Discussion Starter · #18 ·
Personally I would not do the newspaper thing, but it seems to be the popular thing around here.
Sailor24! You recommend what you do not want to do?
After a search I found this thread.

http://www.m5board.com/vbulletin/e3...belts-replacement-fan-clutch-replacement.html

Post#1 says;
One thing I notice when I try to perform the cold start test with newspaper to stop the fan, I can't even stop the fan with either old or new parts.
Make me wonder if there is a better way to check if the fan clutch still in a good condition ?

I think all you need to do is unplug the electric fan and drive the car hard to get it hot. Then listen for it to engage, after or before with it cool, see if the fan spins freely. The dangerous failure is when they lock up and don't spin freely. If it never engages you would likely never have a problem unless your aux fan failed. Some have removed them completely.
I have no idea what the aux fan is. Also at a loss how the fan(s?) and the clutch operate.
 

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Most mechanical fans are primary these are secondary. The electric fan cools the car the mechanical one is back up.
Uh, no. The mechanical fan is the primary cooling fan for this car. If it wasn't, it wouldn't be spinning whenever the engine is running. The auxiliary fan does exactly what its name says. It's for idle and low speed auxiliary cooling of the radiator and A/C condenser.

Try deleting your mechanical fan and see how cool your car runs. It won't.
 

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I'll add a few tips (and then shut up). In the old days, the fan clutch would fail in a loose manner (at least that's what happened to me on an E28). On this M5 it seems to fail in a stiff position meaning trying to stop it with a newspaper, etc is tougher. This means the engine can run a tad cooler as result. That said, unless you examine dozens of cars on an every 3 day basis it is tough to determine what degree of stiffness is normal or not. Also, the temp of the fan clutch obviously will change this parameter too. What I found is that on a hot engine I could previously move the old fan but not get it to spin. Now with the new fan clutch installed if I briskly move it from left to right I can get 2-3 blades to freely pass my hand once I let go. I would say if in doubt, and if the car has more than 125K miles on it I'd recommend changing the fan clutch. It's peace of mind for $250. and if it doesn't need replacement now, it will soon. Lastly, thermostats seem to fail over a timespan of weeks whereas the fan clutch will fail slowly over a few months' duration. At least that's what I think.
 
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