running hot, not overheating

Discuss problems you have had or are having with your Z4
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Athos
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running hot, not overheating

Post by Athos » Thu Jul 11, 2019 8:12 pm

This is driving me mad...

I have bled the car and am near certain that there is no air in the system. The car is using no coolant and I can find a leak anywhere, steam or other wise.

The car will not overheat if on the freeway and moving, when driving free the temp stays dead in the middle of the gauge...

If however you slow down or move onto city streets the guage begins to climb, and then will go back down to normal, and swing back up again, intermittently. I cant seem to trigger it to happen and have tried both the A/C on and the A/C off which does not effect the issue.

Also just as a side note my A/C has been blowing warm air intermittently as well...could the two be related?

HELP!

J

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ph001
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running hot, not overheating

Post by ph001 » Thu Jul 11, 2019 8:18 pm

Both the ac and obviously the main radiator cooling rely on the radiator fan to kick in at the right time to function properly. Are you sure the fan is working?
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Athos
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running hot, not overheating

Post by Athos » Thu Jul 11, 2019 9:02 pm

It appears to be work, I turn on the A/C and the fan will immediately engage. I am wondering if the fan might be intermittently cutting out?

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charlie8
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running hot, not overheating

Post by charlie8 » Thu Jul 11, 2019 9:34 pm

So if you leave running stationary, revving a bit to encourage it, have you actually seen the fan come on to cool and when that happens does the needle move back down then ?

I am not surprised in free driving the temp does not move, in my experience the N52 needs to get quite hot to move the needle, so on normal journeys the stat will do the work alone with the cooled air even at slow speed

Also as said before these fans are electronic and so have speeds - not just off and full. So maybe it gets hots, triggers fan at low speed, that fails, getting hotter, triggers more speed until it finds a level it works, then it cools down. The a/c just triggers a static spin.

Anyway thats what I would do, watch the fan as it gets hot. Jumping straight to full blast and something is wrong.

INPA lets you trigger the % full speeds to test. At 100% it sounds like a tornado
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running hot, not overheating

Post by ph001 » Thu Jul 11, 2019 11:30 pm

Yeh, INPA is great for testing fan. If that all checks out ok you probably might need to start thinking about a sludged up radiator.
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running hot, not overheating

Post by Chris_D » Thu Jul 11, 2019 11:40 pm

As a check to see what your coolant temp actually is you could replicate something I set up recently with the Torque Pro app.
Configure the 'engine coolant' PID on a screen and in the settings there is a configuration to set the polling interval of all PID sensors.
I've been doing this to try to figure out why my car is over-cooling.
I wanted to configure the oil-temp too but this isn't available via OBD sadly. It's on the canbus I think.

It could be useful for you to confirm if it's not just a faulty sender giving weird fluctuations by having a second temp readout to collate the data in real time.
Screenshot_2019-06-28-15-53-13-247_org.prowl.torque.png
Screenshot_2019-06-28-15-53-13-247_org.prowl.torque.png (836.88 KiB) Viewed 110 times
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Athos
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running hot, not overheating

Post by Athos » Fri Jul 12, 2019 1:57 am

Ok so I checked the fan out and it appears to be running correctly , as the motor warms up it turns on and then slowly increases speed. If you turn on the A/C it jumps into turbo mode.

And.. the car once running in slow traffic still gets hot and then will cool down with no apparent change in the fan speed (ac running). Starting to think its the radiator....

Also Chris_d can you please tell me whats involved in the Torque set up? Is it similar to Carly?

Thanks all!

J

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Ewazix
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running hot, not overheating

Post by Ewazix » Fri Jul 12, 2019 6:32 am

I've got Torque Pro, you download it from your mobile app store, pay a couple of quid for the pro version and you will need an OBD2 dongle from ebay/Amazon etc for about £10 for a decent one. It plugs in under the dash. Follow the set up on the screen with bluetooth switched on and you are up and running.
https://youtu.be/UXzu1G9wzpQ
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charlie8
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running hot, not overheating

Post by charlie8 » Fri Jul 12, 2019 8:21 am

WHen trying with car static, and watching fan, which you say ramped in speed - did the needle move ( a/c OFF ) up and down then ?
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Athos
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running hot, not overheating

Post by Athos » Fri Jul 12, 2019 1:13 pm

No the needle did not move when the car was warming up with the a/c off...

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running hot, not overheating

Post by Chris_D » Fri Jul 12, 2019 1:43 pm

Ewazix wrote:
Fri Jul 12, 2019 6:32 am
I've got Torque Pro, you download it from your mobile app store, pay a couple of quid for the pro version and you will need an OBD2 dongle from ebay/Amazon etc for about £10 for a decent one. It plugs in under the dash. Follow the set up on the screen with bluetooth switched on and you are up and running.
https://youtu.be/UXzu1G9wzpQ
What ewazix said.
Useful for me to see it fluctuating between 70-80 where it should ideally be constant 90-95.
You will also be able to record a diagnostic session, complete with map and speeds for later analysis.
Good luck
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charlie8
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running hot, not overheating

Post by charlie8 » Sat Jul 13, 2019 11:37 am

So there is a clue, ONLY with the A/C on does this issue occur

Interesting though as from my understanding the A/C have nothing to do with the coolant or path it takes ? Just the fan is on faster than it might be. So why your temp sensor reads up is strange when its on
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Athos
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running hot, not overheating

Post by Athos » Sat Jul 13, 2019 9:42 pm

Baffling, I am home now and from cold watched the car warm up, at no time did the fan come on...however the needle was dead center the whole time. I drove it around the block and still no fan...

At what temp does the coolant have to be for the fan to come on?

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