M5 overheating at idle and in traffic.

[TouringDan]

Mine routinely runs one needle-width to the right of center in the dead of summer. Remember, I'm in Atlanta where the highway temps usually reach in excess of 110 degrees. (Can't wait to get my A/C compressor installed....LOL)

[TouringDan]

My M5 started doing this yesterday as well. Idling or stopped, the water temp needle would creep to ~3/4 and bob around a wee bit. Never went past 3/4. Once moving, back to 1/2 mark. Hammering at 90mph on country roads, also dead straight at the 1/2 mark. I parked it for now until I have time to investigate.

To me, it sounds like the high-speed on your aux fan isn't kicking on. The Bentley manual has a test procedure for both the low and high settings. It takes about 10 minutes to do

[Grim Reaper]

Mine routinely runs one needle-width to the right of center in the dead of summer. Remember, I'm in Atlanta where the highway temps usually reach in excess of 110 degrees. (Can't wait to get my A/C compressor installed....LOL)

Really? My 3.8 runs a full needle width to the left of center unless I leave it idling in 100 plus degree days here in Dallas, Texas. We usually have a several month run of 100 plus degree days here too.

Even with the AC on and on track days in July and August, it has never been to the right of center.

[TouringDan]

Both of my E34's have run in the same zone

[ramsing]

Yes, but it is the same as the 535
http://www.realoem.com/bmw/partxref.do?part=11527831619

hmm...i'm running a brand new clutch fan from my 525i, when i coverted the 525i to e-fan. so far no issues on the temp. didn't know there's a difference. wonder if there's a need to get a m5/535 clutch fan since the current one is working fine.

My M5 started doing this yesterday as well. Idling or stopped, the water temp needle would creep to ~3/4 and bob around a wee bit. Never went past 3/4. Once moving, back to 1/2 mark. Hammering at 90mph on country roads, also dead straight at the 1/2 mark. I parked it for now until I have time to investigate.

The fan clutch was just replaced a month ago, I'll give it another check tonight and post my findings. It's mechanical so there's always a chance it's failed again. Who knows, maybe there's a dead bird stuck in there.

The same thing happened to me, but I didn't let it get to 3/4 mark. The moment it started moving past the middle mark, I turned off my AC and started coasting. The temp needle then slowly moved down back to the middle point.

Checked the aux fan and it was wobbly and quite weak. Got one replaced, and no issues after. Temps stay just a hair breadth past middle mark when in traffic. But on highway blasts or at night, its a hair breadth before middle mark.

[NikosX]

Really? My 3.8 runs a full needle width to the left of center unless I leave it idling in 100 plus degree days here in Dallas, Texas. We usually have a several month run of 100 plus degree days here too.

Even with the AC on and on track days in July and August, it has never been to the right of center.

This. My car runs about a needle width left of center 99% of the time. Idling in phx traffic at 115 it sits dead center.

Only time it passes middle is if im idling in traffic, drive to mickey D's, run in for 5 Mins and come out. When I start the car the needle will be 2-3 widths past center and within 5-8 seconds its back to center or below.

I might add im about to head into yet another phx summer on original cooling parts.

[CrashTest]

Thanks for the input. Going to re-check the mech fan clutch and take a look-see at the operation of the electric fan. If that checks out, time for a new thermostat and system flush.

[540ii]

Thanks a lot for all the advice, my mechanic is investigating...after reading these posts I will tell him to remove the debris and flush the system and then check the whole cooling system starting with the fan clutch and then the thermostat, water pump, radiator (for obstructions)...I'll let everyone know what the culprit was...thanks again.

[NikosX]

My fan clutch is no longer available. Its on my car now.

[shervin]

Waking up the thread!!!
my E34M5 Temp needle go to the red in traffic (more than 5 min) with or without A/C in ambient Temp over 35 Celsius (95 Fahrenheit).
Fan clutch and AUX fan are working properly.
immediately after running over 40KM/h (more than one minute) temp going back to normal (in the middle).
any body has same issue?
what is the solution

[cirrusblau]

system bled properly?

[shervin]

everything works properly
fan blows very hot air that shows coolant circulates very well and radiator is not clogged
engines produces too much heat!!!

[91e34M5]

Sounds like you're radiator may be restricted or you have a sticking thermostat.

[demetk]

engines produces too much heat!!!

An engine will do that.

[shervin]

If Radiator sticks you wouldn't have very hot air flow through the fan but just warm air because in these cases the radiator cannot heat exchanging properly.
Become a little mysterious...!

[Butler]

Hey guys -

I need to get your take on the same issue that is happening to my 91 E34 M5. The needle on the gauge warms up to the 12 oclock position - but when stopping and idling after getting up to temp, the needle starts creeping up to the right side tick mark. As soon as I start moving again it comes back to 12 oclock.

I thought this meant fan clutch automatically but after reading some of your input, I figured its worth a post before buying new parts. The engine fan spins, I can't say if its spinning slower than normal or not. Would a bad fan clutch not spin at all?

Thanks for the help

[91e34M5]

Hey guys -

I need to get your take on the same issue that is happening to my 91 E34 M5. The needle on the gauge warms up to the 12 oclock position - but when stopping and idling after getting up to temp, the needle starts creeping up to the right side tick mark. As soon as I start moving again it comes back to 12 oclock.

I thought this meant fan clutch automatically but after reading some of your input, I figured its worth a post before buying new parts. The engine fan spins, I can't say if its spinning slower than normal or not. Would a bad fan clutch not spin at all?

Thanks for the help

When your engine gets up to normal operating temperature, your fan should be noisy at rpm's below 2500-3000 as the fan clutch engages to pull more air through the radiator. If you never hear the fan engage at lower rpm's when the engine is hot, then the fan clutch probably needs to be replaced.

[Mfermo]

Hello All, I am a long time reader of this forum but have not posted in a while. I purchased an e34 M5 nearly four months ago. I absolutely love this car. It is my second E34, the previous being an 540/6. I am having one problem with the car. It is overheating after idleing for a long time (e.g >10 minutes) and also overheating after being in traffic for more then 10-15 minutes. I have noticed a lot of dirt and debris in the coolant reservoir, could this be causing this problem? (if so how could i remedy it?). I was told it could be the auxillary air fan, which i dont believe i hear kicking in. Any ideas on how to begin addressing this problem is appreciated.

Check the fan clutch while engine is running by trying to stop the fan with a piece of cardboard if that cardboard stops the fan then you need to get the fan clutch which is one of your solutions the other is your auxiliary fan make sure that fan works.

[shogun]

Fan Clutch test
First, lets discuss what the fan clutch does and why it is there. The fan clutch is just what the name says, it is a mechanism that will clutch the fan on and off depending on the need for more or less cooling air to flow thru the radiator. It is a thermostatically controlled device that when operating normally will vary the fan speed independently of the engine speed. When cruising down the road at freeway speeds, with outside temperature less then desert conditions, the fan should be merely be idling along, turning just fast enough to add a little air flow when needed, in this way the fan noise and drag on the engine is greatly reduced. When reducing speed, the fan clutch will sense higher temperatures thru the radiator and “clutch up” thereby increasing the fan speed to help maintain constant engine temperature. It may in fact, cycle as the temperature of the air thru the radiator changes depending on airflow. If the fan clutch operation is normal, when first starting the car, the fan clutch should “clutch up” and an increase in noise and airflow should be obvious. After about 60-90 seconds, the fan will un-clutch and the noise and airflow will drop. The fan will continue to turn but at a much reduced speed. As the engine warms and the thermostat opens to regulate the temperature, the air thru the radiator gets hotter and the clutch will sense this, thereby increasing the speed of the fan to maintain a normal operating temperature.
First signs of trouble:
A normal temperature indication at freeway speeds and an increasing temperature as the vehicle slows is one of the first indications of trouble. Many other things may give this indication but if the temperature seems to be stable at speeds but climbs in traffic or while stopped, this is a good indication that the fan clutch isn’t working correctly. As the temperature continues to climb, the auxiliary electric fan should start but may not provide enough air to keep the engine from overheating.
Another sign of trouble is if the fan noise is high and never decreases after starting, and is there anytime the engine RPM is higher then idle, this means that the fan clutch is “frozen” and is not releasing. Although this will not result in immediately serious trouble, it will load the engine continually and gas MPG will be reduced. Load on the fan belt(s) will be higher and shorten the life of that component also.

Testing the fan clutch:
If you have reason to suspect that the fan clutch is defective, here is the recommended procedure to verify the condition of the fan clutch.
1. Start the car (cold) with the hood open and note if the fan is turning, increase the engine RPM and note if the fan turns faster and the noise increases, if it does, first good indication, if it does not increase speed/noise, clutch is bad and needs to be replaced. (Remember, this must be tested after the car has been off for and extended period, over night etc.)
2. Leave engine running and note if the fan starts to slow down after 2-5 minutes, speed/noise should diminish and even raising the RPM, the fan should not make as much noise as when first starting, if it does slow, this is the second good indication. If speed/noise does not decrease, clutch may be “frozen” and should be replaced.
3. Leave the engine idle and watch the temperature indicator. When normal operating temperature has been reached, some increase in fan speed/noise should be noted, in particular when the RPM is increased. If temperature is fairly stable and the fan noise/speed increases or cycles, third good indication. If temperature indication continues to increase, with no increase in fan noise/speed, clutch is defective and should be replaced.
4. After the engine is at normal operating temperature or above, is the only time that the “rolled up newspaper” test that many people talk about should be performed! Take some newspaper and roll it up into a long narrow tube. Be carefull, keep hands and fingers away from the fan while performing this test! With the engine at full operating temperature and idling, take the rolled up paper and insert it on the back side of the fan and try to reach the hub of the fan avoiding the blades until close to the hub. Push the rolled paper at the fan increasing the friction to the hub area of the fan. If the fan can not be stopped easily this is the fourth good indication, if it can be stopped the clutch is defective and should be replaced. Again, this test can only be performed when the engine is at or above full operating temperature.
Testing can be performed in any order but just make sure the conditions during testing are those that are specified for that specific test.
Do not continue to operate the engine if the temperature continues to rise and certainly stop if the temperature approaches “redline”.

[NikosX]

Waking up the thread!!!
my E34M5 Temp needle go to the red in traffic (more than 5 min) with or without A/C in ambient Temp over 35 Celsius (95 Fahrenheit).
Fan clutch and AUX fan are working properly.
immediately after running over 40KM/h (more than one minute) temp going back to normal (in the middle).
any body has same issue?
what is the solution

If it made it to the RED, you've got a problem. Compression test to make sure you did not warp the cylinder head.

- - - Updated - - -

Hey guys -

I need to get your take on the same issue that is happening to my 91 E34 M5. The needle on the gauge warms up to the 12 oclock position - but when stopping and idling after getting up to temp, the needle starts creeping up to the right side tick mark. As soon as I start moving again it comes back to 12 oclock.

I thought this meant fan clutch automatically but after reading some of your input, I figured its worth a post before buying new parts. The engine fan spins, I can't say if its spinning slower than normal or not. Would a bad fan clutch not spin at all?

Thanks for the help

Check the AUX fan on its low and high speed settings. Also check your viscous fan clutch. Might be time to flush the cooling system and or replace your radiator. How many miles on the engine?

[cirrusblau]

Hey guys -

I need to get your take on the same issue that is happening to my 91 E34 M5. The needle on the gauge warms up to the 12 oclock position - but when stopping and idling after getting up to temp, the needle starts creeping up to the right side tick mark. As soon as I start moving again it comes back to 12 oclock.

I thought this meant fan clutch automatically but after reading some of your input, I figured its worth a post before buying new parts. The engine fan spins, I can't say if its spinning slower than normal or not. Would a bad fan clutch not spin at all?

Thanks for the help

when it goes past the middle, does it come to a point where it stops and stays there (in traffic)? i have a suspicion that there differences in the temp gauge behavior between the 3 versions of instrument clusters. the gray back, which is the oldest version (which i have) i suspect has an un-dampened temp gauge. i have an 80/88 double temp switch and my aux fan switches to when i gets past the middle of the gauge. i don't know it this is true, maybe shogun can prove/disprove?

[Butler]

Check the AUX fan on its low and high speed settings. Also check your viscous fan clutch. Might be time to flush the cooling system and or replace your radiator. How many miles on the engine?

Well, funny thing there - my aux fan and AC isnt working. I did, since posting, find out that the waterpump and tstat have 18,000 miles on them. The radiator and Fan clutch are original with 196k miles.

[BleedsBlue]

You can thoroughly test the fan clutch as explained above, but if it's real bad you can tell the clutch is shot without even starting the car. The fan should not spin freely when the car is off, there should be resistance. If you can spin it freely at all, it's only a matter of time before the fan clutch goes. In these temp ranges the fan is very important.

[shervin]

If it made it to the RED, you've got a problem. Compression test to make sure you did not warp the cylinder head.

- - - Updated - - -

Thanks for your reply.
There is no problem with compression. all cylinder shows about 180psi of pressure when cranking (with 4 psi deviation).
even I've checked the cooling system for leackage by pressure test about 12psi in about 20 minute. no pressure drop seen.
20160420_122611.jpg
20160420_122619.jpg
I've used my initiative to replace the wires of temp switch to have max fan speed in 91 degree (mine has 91-99 temp switch).
in these days with ambient temp about 20 degree it works well
the aux fan start full speed in 91 and in about 5 min it goes off. but I believe one month later when the weather gets warmer, I'll be in trouble of overheating again!

[Butler]

Hi guys,

I thought I should bump this thread to say that my car isn't over heating any more... Im glad, don't get me wrong, but I didnt do anything.

Second thing, I left my lights on a few days ago. I came out to the car, battery weak as hell, and when I turned the key it took a few slow cranks before coming to life as you'd expect. Lucky! The funny thing was that the AC and Recirc lights were both on for about 20 seconds. They have since gone off again and not returned. Why did they light up momentarily? That was the first time I've seen them on since getting the car.

Thanks