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Discussion Starter #1
Hi all. This is the second summer I've been driving my M around and I wanted to toss around ideas for things to do that'll ensure the fickle cooling system on these things is working really well.



What we know so far is the Cadillac option of replacing the radiator assembly with a Zionsville model. From what I understand, the actual cooling performance of these things is still going to be just on-par with the existing system for normal driving, but presumably more longevity compared to the OEM system.


There's a thread on improving cooling for track days. The problem here would be that I'd consider a lot of these relatively extreme - installing new oil coolers, ripping out foglights, etc.


2 recent events got me thinking about doing something with the system: A close-to-overheat event while attempting to teach someone stick (the car frequently starting in an isolated position), and high temps on an extremely hot (~95F) standstill traffic situation. The system was overhauled with all-OEM parts probably 3 years ago at this point, which makes me think the latter situation at least shouldn't be happening.



So some concrete questions:

  1. What are typical/acceptable fluid temps? I've installed a new Head Unit with the I-Bus App and my coolant supposedly hovers around 100C according to it. This is when my coolant temps are in the dead center of the gauge. I'm wondering if I need to calibrate the app?
  2. What preventative maintenance (as opposed to new equipment) do you do for the system? What's your go-to fluid mix?
  3. Any other first hand experiences with non-OEM parts or solutions? I'm the "OEM was 20 years ago" type of owner, and think that often some of the issues in these cars have been solved with revisions or creative solutions in the aftermarket.
 

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Does your aux fan work? I owned my car for 4 years and didn’t even realize it was fried. Only reason I checked was because my coolant temps got high while idling. I do notice lower temps now that the fan has been replaced.
 

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Coolant temps are pressurized, so I wouldn't worry about overheating. But the aux fan should be running with the AC engaged. There is also an upgrade for the mechanical fan, someone recently did a write-up. That would help at low speeds. I believe it was an E60 fan with more blades.

Regards,
Jerry
 

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Discussion Starter #4
Does your aux fan work? I owned my car for 4 years and didn’t even realize it was fried. Only reason I checked was because my coolant temps got high while idling. I do notice lower temps now that the fan has been replaced.
I'll double check it today for sure, but I kind of assumed if most the time my temps were rock solid/stable then it would be going for me.
 

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I have a long commute with both standstill and highway cruising, so as the weather gets hotter I've kept a close eye on KTMP. Once the car ia fully warmed up with A/C on the KTMP hovers around 88-91 at idle and 84-86 on the highway. Turning the A/C off brings those temps down about 3 degrees. Should I be concerned that they're too high?

I've recently replaced the water pump, fan clutch, and thermostat (79C). I've also removed all of the debris from around the outside of the radiator and reverse-flushed it.

Sent from my VS988 using Tapatalk
 

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Bad fan clutch? Idling with oil temps hot it should be pulling a lot of heat, you can really feel the airflow and heat.



Thise temps are fine, i like redline watter wetter. Didn't keep track but the needle seem to be on the cooler side after adding it.
 

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Had a shock with mine a few weeks ago - hot day in UK, 28-30 degrees C.... just done 100 miles on motorway and was driving last few miles around local roads to office when engine overheat message popped up and I notice needle was climbing rapidly towards red... pulled over and switch off, checked around engine bay and all looked ok. Restarted and it seemed ok and idled without overheating. I had AC on which didn’t help.

Further testing shows my aux fan is toast - not working at all despite only being replaced 4ish years ago. Crap design does not seem to last at all.

So I’d check your aux fan and make sure it’s working - if it is your car will stay cool in virtually all circumstances.

Simon
 

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Had a shock with mine a few weeks ago - hot day in UK, 28-30 degrees C.... just done 100 miles on motorway and was driving last few miles around local roads to office when engine overheat message popped up and I notice needle was climbing rapidly towards red... pulled over and switch off, checked around engine bay and all looked ok. Restarted and it seemed ok and idled without overheating. I had AC on which didn’t help.

Further testing shows my aux fan is toast - not working at all despite only being replaced 4ish years ago. Crap design does not seem to last at all.

So I’d check your aux fan and make sure it’s working - if it is your car will stay cool in virtually all circumstances.

Simon
What was the brand of the fan? Could it be the fuse?
 
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