Running hot

[TravL350]

You’re both right, it’s glass filled plastic / composite. Same thing. That’s what the “PPS-GF40” designates

[TravL350]

That’s a cast metal impeller

[Obioban]

Sounds like case solved.

[Bigo1087]

Sounds like case solved.

What was the solution?

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[jet_dogg]

What was the solution?

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OP has non-oem metal impeller water pump which theoretically flows less than composite impeller oem.

[TexaZ3]

OP has non-oem metal impeller water pump which theoretically flows less than composite impeller oem.

Its not as clear cut as Ian makes it sound as I'm yet to make changes and confirm they have any effect. Though likely he is correct, I had this pump installed for a while and never experienced any overheating before. So, while the pump might not be helping the cause, it is certainly not the main (or the only) culprit here.

[Tbonem3]

Yes it's radiator, but I would still return pump to fcp and get oe.

[TexaZ3]

Yes it's radiator, but I would still return pump to fcp and get oe.

Yep, that's the plan.

[robgill]

Helpful thread! I'm having a similar issue I'm chasing and need some feedback. When it is hot out (above 80), the A/C on, and in traffic or slow speed my water temp will creep towards the 3rd dot. It never goes above ~215F and will come back down to middle when the Aux fan speed increases. It is fine at speed and lower ambient temps. Oil temp stays in the middle. My experience has been that when everything is working properly the water temp never leaves middle and I want to get this car to behave that way. Its also my experience that when these cars overheat it happens fast so I constantly stress about the water temp on hot days...

Basically everything in the cooling system is new. Including new Aux fan, a/c condenser, water pump (OEM Geba), fan clutch (Behr), fan switch, hoses and seals. I kept the CSF radiator installed by the previous owner.

My theory is that the Aux fan is not increasing speed soon enough to hold the temp down. I tested this by waiting for the temp to increase, then I unplugged the fan switch in the lower hose. When the fan switch is unplugged the aux fan defaults to max speed. This showed me two things: first that as the water temp is rising, the fan is not running at max speed. Second when it does run at max speed it immediately cools down and drops water temp back to middle.

So why is the aux fan not running fast enough to cool? Two ideas: First is that the CSF radiator is affecting the balance of the system some how and is requiring more airflow than the stock aux fan curve settings in the DME. Second would be that the aux fan curve settings in the DME are changed/wrong (this DME has seen a LOT of mods...). So I'm going to try and figure out how to adjust the fan curve. I could also take out the CSF radiator and go back to OEM. Anyone have any other thoughts/ideas?

[repoman89]

Helpful thread! I'm having a similar issue I'm chasing and need some feedback. When it is hot out (above 80), the A/C on, and in traffic or slow speed my water temp will creep towards the 3rd dot. It never goes above ~215F and will come back down to middle when the Aux fan speed increases. It is fine at speed and lower ambient temps. Oil temp stays in the middle. My experience has been that when everything is working properly the water temp never leaves middle and I want to get this car to behave that way. Its also my experience that when these cars overheat it happens fast so I constantly stress about the water temp on hot days...

Basically everything in the cooling system is new. Including new Aux fan, a/c condenser, water pump (OEM Geba), fan clutch (Behr), fan switch, hoses and seals. I kept the CSF radiator installed by the previous owner.

My theory is that the Aux fan is not increasing speed soon enough to hold the temp down. I tested this by waiting for the temp to increase, then I unplugged the fan switch in the lower hose. When the fan switch is unplugged the aux fan defaults to max speed. This showed me two things: first that as the water temp is rising, the fan is not running at max speed. Second when it does run at max speed it immediately cools down and drops water temp back to middle.

So why is the aux fan not running fast enough to cool? Two ideas: First is that the CSF radiator is affecting the balance of the system some how and is requiring more airflow than the stock aux fan curve settings in the DME. Second would be that the aux fan curve settings in the DME are changed/wrong (this DME has seen a LOT of mods...). So I'm going to try and figure out how to adjust the fan curve. I could also take out the CSF radiator and go back to OEM. Anyone have any other thoughts/ideas?

I made a recent thread in the coding section about the aux fan curve and got good answers. Check it out. I was modifying my fan curve for a Spal electric fan conversion … wanted it to max out at a cooler temp since I replaced two fans with one. I think I need to go cooler still since I creep past vertical on occasion, but never anywhere near the dot.

[bimmer]

Helpful thread! I'm having a similar issue I'm chasing and need some feedback. When it is hot out (above 80), the A/C on, and in traffic or slow speed my water temp will creep towards the 3rd dot. It never goes above ~215F and will come back down to middle when the Aux fan speed increases. It is fine at speed and lower ambient temps. Oil temp stays in the middle. My experience has been that when everything is working properly the water temp never leaves middle and I want to get this car to behave that way. Its also my experience that when these cars overheat it happens fast so I constantly stress about the water temp on hot days...

Basically everything in the cooling system is new. Including new Aux fan, a/c condenser, water pump (OEM Geba), fan clutch (Behr), fan switch, hoses and seals. I kept the CSF radiator installed by the previous owner.

My theory is that the Aux fan is not increasing speed soon enough to hold the temp down. I tested this by waiting for the temp to increase, then I unplugged the fan switch in the lower hose. When the fan switch is unplugged the aux fan defaults to max speed. This showed me two things: first that as the water temp is rising, the fan is not running at max speed. Second when it does run at max speed it immediately cools down and drops water temp back to middle.

So why is the aux fan not running fast enough to cool? Two ideas: First is that the CSF radiator is affecting the balance of the system some how and is requiring more airflow than the stock aux fan curve settings in the DME. Second would be that the aux fan curve settings in the DME are changed/wrong (this DME has seen a LOT of mods...). So I'm going to try and figure out how to adjust the fan curve. I could also take out the CSF radiator and go back to OEM. Anyone have any other thoughts/ideas?

It's the CSF radiator. I just went through this. Drove me nuts trying to figure it out. Replacing with OE BMW radiator fixes the issue.

[Tbonem3]

Someone asked my in my journal why I didn't get a csf oil cooler when I bought a new OE one.

Can't beat OE sometimes.

[TexaZ3]

Someone asked my in my journal why I didn't get a csf oil cooler when I bought a new OE one.

Can't beat OE sometimes.

Honestly, on stuff like that - most of the time.
They invested $$$$ into physical research vs. some aftermarket company that just did some R&D in "theory".

[jet_dogg]

We've been beating a dead csf horse lately.

[sapote]

Remove the old dirty rad and clean up the AC condenser with garden hose jet water shooting forward, and do the same on the rad to clean the dust off. This can help to transfer the heat better.