Overheating on track. Looking for the definitive solution.

[TACOM3EAT]

Howdy community.
Curious who has dealt with serious overheating issues on track and been able to solve them.

I have an '05 6MT 90k miles. Cooling system is all stock. Clutch fan was replaced around 25k miles ago. Water pump & thermostat were replaced around 30k ago. Radiator and oil cooler were cleaned out, fresh coolant with a 60/40 distilled water plus water wetter added and flushed properly and thoroughly. There was some residue in the old fluid that points to OEM rad starting to fail. Coolant temps creep up after a few laps, blowing heater on max helps for a lap or so, but then coolant temps creep up again, almost to the second dot & to the point where I had some boil over from the overflow. This is at altitude (HPR in Colorado) and in high heat 95-100 degrees. Car has performed flawlessly in identical conditions in previous years. Temp is never an issue on the street, even doing canyon runs in high heat with a/c on.

So to my question finally:

If you have had these issues, how did you solve them?

I know plenty of people who run the assorted aluminum rad options (CSF, Koyo, Mishi). If there were cooling issues before those "upgrades" they seem to persist even with install of the new radiators. I assume my stock radiator is on the way out, I would hate to pay money for a new system and still have the same issue, I see that happen all the time.

Is the Zionsville rad a sure-fire cure? Fluidyne?

CSF reviews seems hugely mixed, but it seems like a great product, triple pass etc.

Is an electric fan better than a clutch fan for pure cooling power?

Thanks, I know there are plenty of snippets around the web on this matter but I'm looking for someone who has had this happen and exactly how they were able to fix it. (Hopefully you're out there lol)

Grazie Mille.

[eacmen]

Double check thermostat actually works by watching it open in boiling water.

Had no issues with my CSF radiator. I would stick with OE oil cooler. If you still have A/C then replace the condensor as well since it sits in front of the radiator.

Make sure you still have all the plastic ducting it makes a difference.

Since this happened at speed on track with plenty of air forced over the rad it likely isn't a fan issue.


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[foolio]

Not sure what your plan is for the car but here is what I run on a dedicated track car:

• cooling components (Rad, water pump, t-stat, etc.) are all stock
• removed mechanical clutch fan. Doesn’t do anything at speed but block airflow.
• N15 Design hood vents
• one bottle water wetter, the rest pure distilled water. Don’t leave it like this if your car sees freezing temps over winter
• Completely removed AC. Getting rid of the condenser from front of the radiator really helps
• clean radiator and oil cooler thoroughly to remove debris

[sc_tr0jan_m3]

i'm down in texas and ran my car with over 100 degs and some nasty humidity. i run a BW oil cooler and CSF rad with the oem fan and AC still installed. no problems and although the gauge for the oil/water temps crept up, via data they still showed steady 200 degs for oil and about 240-250 degs for water. for the rad, i use mostly distilled water with wetter.

[bigjae46]

I have a CSF radiator, aluminum expansion tank, high pressure cap and deleted heater core. I plugged the water pump and the end of the water pipe. So no loop. The expansion tank is in the drug bin which reduces exposure to heat from the engine.

I have a new OEM oil cooler and a secondary oil cooler. Hood is vented as well.

Never had water temp issues until I removed the SPAL fan. With the fan, never saw temps over 205. Without the fan, I have issues with water temps going up in lower speed sections, when I'm behind someone and in turns.

I've always had more issues with oil temps. They still get up to 270-280. I'm using BMW Shell 10w-60. I've been thinking about switching to a different brand or lower viscosity oil.

[pMak26]

I've always had more issues with oil temps. They still get up to 270-280. I'm using BMW Shell 10w-60. I've been thinking about switching to a different brand or lower viscosity oil.

I'm the same, I just had a lovely chat with the folks at bimmerworld. They highly suggested switching to Red Line 50wt. Either the 50wt Race if you have headers/removed the cats, or Red Line High Performance 15W50 if you have stock headers/cats. Being that I still have stock headers, I'm giving the 15w50 a shot. Fingers crossed I make it to NASA NJMP at the end of the month and can report back.

I run the oil up to 280*, but then I always back out of it and start shifting at 7k. The oil temp drops very quickly when I back off, but I don't have the nerve to push it higher. I'm currently on Liqui Moly 10w-60 GT1.

[eacmen]

I'm the same, I just had a lovely chat with the folks at bimmerworld. They highly suggested switching to Red Line 50wt. Either the 50wt Race if you have headers/removed the cats, or Red Line High Performance 15W50 if you have stock headers/cats. Being that I still have stock headers, I'm giving the 15w50 a shot. Fingers crossed I make it to NASA NJMP at the end of the month and can report back.

I run the oil up to 280*, but then I always back out of it and start shifting at 7k. The oil temp drops very quickly when I back off, but I don't have the nerve to push it higher. I'm currently on Liqui Moly 10w-60 GT1.

Not to sway you one way or the other but Red Line is a Bimmerworld sponsor in their race series. It is probably a fine oil but also may influence their suggestion.

Also BW is likely changing that oil between each race weekend.


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[S14]

Howdy community.
Curious who has dealt with serious overheating issues on track and been able to solve them.

I have an '05 6MT 90k miles. Cooling system is all stock. Clutch fan was replaced around 25k miles ago. Water pump & thermostat were replaced around 30k ago. Radiator and oil cooler were cleaned out, fresh coolant with a 60/40 distilled water plus water wetter added and flushed properly and thoroughly. There was some residue in the old fluid that points to OEM rad starting to fail. Coolant temps creep up after a few laps, blowing heater on max helps for a lap or so, but then coolant temps creep up again, almost to the second dot & to the point where I had some boil over from the overflow. This is at altitude (HPR in Colorado) and in high heat 95-100 degrees. Car has performed flawlessly in identical conditions in previous years. Temp is never an issue on the street, even doing canyon runs in high heat with a/c on.

So to my question finally:

If you have had these issues, how did you solve them?

I know plenty of people who run the assorted aluminum rad options (CSF, Koyo, Mishi). If there were cooling issues before those "upgrades" they seem to persist even with install of the new radiators. I assume my stock radiator is on the way out, I would hate to pay money for a new system and still have the same issue, I see that happen all the time.

Is the Zionsville rad a sure-fire cure? Fluidyne?

CSF reviews seems hugely mixed, but it seems like a great product, triple pass etc.

Is an electric fan better than a clutch fan for pure cooling power?

Thanks, I know there are plenty of snippets around the web on this matter but I'm looking for someone who has had this happen and exactly how they were able to fix it. (Hopefully you're out there lol)

Grazie Mille.

Hello fellow HPR overheater, I had the same problem last weekend!

I was experiencing overheating in hot environments before, what solved it so far is new OEM water pump/thermostat/hoses/expansion tank/fan clutch/fan/all shrouding and a CSF oil cooler and radiator with water wetter and 60/40ish mix of bmw coolant and distilled water. I still overheated on track though. Chatting with Mark from SCR, he suggested failing o2 sensors and MAF sensor can make the car run lean (which makes it hot) and I pondered about my tune which was a custom dyno tune on 93. I threw a 1/2 tank of 100 octane in the car and the temps were far more manageable, so I think my tune might be too aggressive for track duty on 91 octane.

I want to keep this a street car, so venting the hood is a bit too far for me at the moment, although I think it really helps. It seems that overheating on track environments is quite common, but also some people have zero issues with it.

[SteelGreyM]

Not sure what your plan is for the car but here is what I run on a dedicated track car:

• removed mechanical clutch fan. Doesn’t do anything at speed but block airflow.

Interesting that people say that. Mine went bad once and I couldn't drive my car much at all without it almost overheating. Not even on the highway in 6th gear at 70mph. The second I installed the replacement it was back to normal.

[jk715]

Recently had similar issues with heat on track only. Did a cooling system refresh with a 80/20 mix and upgraded to CSF oil cooler. There was a ton of debris in the radiator fins which was also cleaned out. Also removed the clutch fan and modified the aux fan to run at 25% when idle vs not at all.

No issues so far. Prior to the refresh shifting early and cool down laps got me through the day.


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[eacmen]

Correct me if I'm wrong but isn't the point of the mechanical fan at speed is to create a low pressure zone behind the radiator to direct the airflow over the rad?

There is plenty of air hitting the car but you need that low pressure to direct the air over the rad?

[jk715]

Im sure a low pressure zone is created especially at idle. At speed, air flow through radiator seems to be sufficient without the clutch fan. I wouldn’t recommend for anyone who sits in traffic or even a daily driver.

Primary reason for removal for me was to free up some load. Peace of mind for possible fan explosion helps also.


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[TACOM3EAT]

Hello fellow HPR overheater, I had the same problem last weekend!

I was experiencing overheating in hot environments before, what solved it so far is new OEM water pump/thermostat/hoses/expansion tank/fan clutch/fan/all shrouding and a CSF oil cooler and radiator with water wetter and 60/40ish mix of bmw coolant and distilled water. I still overheated on track though. Chatting with Mark from SCR, he suggested failing o2 sensors and MAF sensor can make the car run lean (which makes it hot) and I pondered about my tune which was a custom dyno tune on 93. I threw a 1/2 tank of 100 octane in the car and the temps were far more manageable, so I think my tune might be too aggressive for track duty on 91 octane.

I want to keep this a street car, so venting the hood is a bit too far for me at the moment, although I think it really helps. It seems that overheating on track environments is quite common, but also some people have zero issues with it.

I’m actually curious if the residual smoke in the air from the Fort Collins fire was enough to be the straw that broke the cooling camels back. Altitude, heat and 8,200 RPM are cooling challenges plenty without the addition of thick smoky air. Just a thought.


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[elbert]

. Water pump & thermostat were replaced around 30k ago.

Which water pump did you use?

[TACOM3EAT]

Which water pump did you use?

Honestly couldn’t tell you. 30k miles was 6-7 years ago


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