Help diagnosing high water temps at track - Resolved? (not really!)

[S14]

It makes me wonder if the algorithm in recaptures box displays the readings a bit low. I think I'll run the secret menu next time I'm at the track and compare the OBC's value vs. recapture's value.

[GolanM3]

I've been watching the OBD II display very closely for the last couple of weeks while trying to troubleshoot my overheating issues. At 85c/195f it is at dead center point, once I reach/surpass 95c/203f is there the needed starts to move towards the 3/4 dot. I've see it up to 98/208 for a short moment and it didn't go beyond the 3/4 dot. As you've noted, for many other vehicle that would still be considered within operating range.

[BigRussia]

Spent last weekend at Mid-Ohio and I still have an overheating problem as well. I was also running Racecapture datalogging with their E46 CAN data and noticed that the racecapture box was showing that the needle moves off center at 185F and is at the right dot at 190F. Highest temps I saw was 193F which seems to be normal operating temp for most vehicles.

Does anybody else with "overheating" issues have actual temp values recorded when the overheating happens?

That seems too low a temp for the needle to moving off center let alone hitting the 3/4 dot. I didnt have any values when I encountered the track overheating issues that prompted me to create this thread, but since then Ive got a Ultragauge running off the OBDII displaying the coolant temp. Warming up it seems to get to center at around 185*F, and driving around on a hot July day pushing the car to get hot purposely I've gotten to as high as 201*F / 94*C and still the needle did not move from 12 o'clock center.

[S14]

Spent last weekend at Mid-Ohio and I still have an overheating problem as well. I was also running Racecapture datalogging with their E46 CAN data and noticed that the racecapture box was showing that the needle moves off center at 185F and is at the right dot at 190F. Highest temps I saw was 193F which seems to be normal operating temp for most vehicles.

Does anybody else with "overheating" issues have actual temp values recorded when the overheating happens?

[sapote]

I checked the the connection to the AUC sensor last night out of curiosity and it was not fully seated, ergo the stock electric fan was not activating at all.

I think you were talking about the sensor on the radiator lower hose, and it is the coolant temp sensor, not AUX fan sensor (but the DME read the coolant sensor and control the AUX fan).

[jk715]

Yup, aux is in stock location with no (clutch) puller fan. the z4m setting really just enables the fan when idle/low temp on start. AC still there for those long drives to the track.

[BigRussia]

I've been running with just the aux fan (z4m settings) on track/street with no issues (after a complete cooling refresh with mostly oem parts). Temps will go up but a cooldown lap or turning on the heater for a lap will bring temps back down.

One thing that took a while to figure out was that the underbody tray/splitter was needed to prevent hot air from being trapped in the front of the engine bay. When running without the splitter/tray the ambient temps would creep up 10-15*F above actuals and the oil temp would be slightly affected by this as well. Adding the splitter/tray back the ambient temp dropped back to normal and oil temp was back to normal.

So you left the Aux fan in its stock location and just using the Z4M aux fan settings? With no main puller fan behind the radiator?

If so I assume at least AC should be fine, I'd just be worried about coolant temps for myself personally due to my environment. Regardless, it comes down to individual's location/climate and whether AC is important to you. Not sure where you're located, or if you still have AC (cause if not I'd imagine you wouldn't still have the condenser and that helps alot with flow, no longer having it in front of the radiator).

[Fresh1179]

Fresh1179

I considered switching to the Z4M Aux fan settings using the binary modification tool, but don't know if that'll make it run too much (since on the Z4M it acts as the primary fan to my understanding) and just cause extra wear to it, so yeah so far the Aux fan is all factory and I don't plan to remove it due to the factors of being in a hot climate, too much traffic (even though car is not a daily, but still catch traffic regularly), and needing my AC icy ha.

That is exactly what I am talking about. My fan nomenclature is still terrible despite lurking around here for a while. The Aux fan. I am in the same boat with respect to retention of the fan. This car will cook me alive without AC in the NC heat/humidity. After a 30 minute session it looks like I got attacked by a Super Soaker. I can't imagine what it is like in FL. Let me know if you go down the Aux fan modification route, I may PM you with some questions.

[BigRussia]

Fresh1179 Do you mean the stock Aux pusher fan that is front of the condenser? If so yes, mines all original and hasn't been messed with or modified and has its shroud (I dont have the shroud behind the rad for the main puller fan, just the mishimoto fan mount 'shroud' with the 16" mishimoto e-fan). Its too hot down here in SFL to not have it and with the stupid amount of traffic we have my AC would be useless if the factory Aux fan wasn't still there. Ive seen it running with the AC on, and sometimes when the cars nice and hot, so thankfully seems to be working to spec.

I considered switching to the Z4M Aux fan settings using the binary modification tool, but don't know if that'll make it run too much (since on the Z4M it acts as the primary fan to my understanding) and just cause extra wear to it, so yeah so far the Aux fan is all factory and I don't plan to remove it due to the factors of being in a hot climate, too much traffic (even though car is not a daily, but still catch traffic regularly), and needing my AC icy ha.

[Fresh1179]

GolanM3 BigRussia
Interesting development on my end. Do y'all still run the stock electric fan in front of the radiator or did you remove it when you went to a Non-OE setup with a SPAL fan? For that matter, do you still have the stock shroud in place with the attachment point for the AUC sensor? I checked the the connection to the AUC sensor last night out of curiosity and it was not fully seated, ergo the stock electric fan was not activating at all.

My supposition based off staring at some data is that the non functional stock mech fan blades were essentially functioning as an air dam preventing airflow through the engine bay. You can "manually" activate the fan by putting the AC on low (fan will reach high speed setting) if your car is still equipped with the fan. I am not familiar with the DME conditions for activation of the fan under different operating conditions but I am certain that the AUC sensor was non-functional therefore there would be no input to the DME indicating a heat condition or activation of the AC requiring the activation of the stock electric fan. I don't know if the DME relies on info from the coolant temp sensor so don't hold me to any of this. I do know that with the AUC sensor cleaned and properly connected I can activate the fan on high which gives me some hope.

[Obioban]

I’m assuming you are running stock pully’s and the clutch fan? It is going on I bore a hole in my soul to yank out a $1700 Zionsville radiator. Best craftsmanship I’ve seen in an aftermarket part to date. ::sigh:: time to reopen those clutch fan knuckle scars it seems…

Edit: Off topic, but what track did you run? Always interested to hear. I live in NASCAR land, but we have some super road tracks around here.

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I under drive the power steering pump (I also have it's output pressure reduced by 25%, so it should wash out). Other than that, yes.

I have a friend with an e39 M5 that also started having overheating issues after installing the Zionsville rad. It is sad, as, as you say, it's a really nicely made piece.

On my M3 coupe, I do not run the stock clutched fan or aux fan. I have a SPAL fan that is coded to the Z4M aux fan temp vs speed values (Z4M only has an Aux fan stock, so its fan curve is designed for no clutched fan). I do that to lighten the front end and make working on the car easier, but it probably improves on track cooling as well (as none of the stock ducting exists to limit air flow). That said, I have not and will not do it on my M3 wagon, as it makes the AC pretty useless on a hot day with the car is not in motion. I'm okay with that in the coupe, as my usage for it pretty much never sees traffic, but for any car that does this is a non starter IMO.

During COVID, I've mostly been doing Thunderbolt and Lightning at NJMP, as they're close enough that I can sleep at home. In normal times, when having a hotel room is more tolerable, Summit point, Mid Ohio, Limerock, formally Watkins Glen (trying to not, as the walls are close), etc. I try to hit up VIR once a year (generally in November, for the 3 day PCA event) as IMO it's the best track in the country, but with a 500 mile drive each way, I don't do it TOO often.

Edit: just read your actual question. You said "did", I read "do".

I was at Lightning, at NJMP.

[Fresh1179]

I'd try the tune, first, as it's a free/easy check, but the CSF rad is certainly a prime suspect.

Just got back from a weekend of 95 degree+ sessions, coolant temps never went past vertical. OE BMW rad.

I’m assuming you are running stock pully’s and the clutch fan? It is going on I bore a hole in my soul to yank out a $1700 Zionsville radiator. Best craftsmanship I’ve seen in an aftermarket part to date. ::sigh:: time to reopen those clutch fan knuckle scars it seems…

Edit: Off topic, but what track did you run? Always interested to hear. I live in NASCAR land, but we have some super road tracks around here.

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[bimmer]

Stock

A new OE BMW and you still had issues? Or stock as in original or one that has seen some use before the issue appeared? If the later, I would definitely replace the CSF with OE BMW. I chased the exact problem you are having for a while trying to make the CSF work. I ended up replacing the CSF with new OE BMW and it instantly fixed it.

[GolanM3]

What radiator were you running prior to replacing with the CSF?

Stock

[bimmer]

Hi everyone, I'm so glad I found this post. I have a 2003 M3 that I use for mostly track driving.
I have the same exact symptoms as was BigRussia describing. The car never overheat in traffic or any other condition, however at the track, only after a few laps and it goes past the half point.
So far I upgraded both radiator and oil cooler to CSF, replaced WP, thermostat and fan clutch. Pretty much every component in the cooling system, and still things have not gotten any better. I also thought I had head gasket issue, but my mechanic checked and confirmed no issues there.
Now what's interesting, is that I also have the TTFS tune (after install of euro headers). In addition, last night I used the OBD port to check coolant temps, and I see that temp gauge goes beyond the half point at around 205 degree, is that considered over heating? is there any buffering in the stock temp gauge that possibly the TTFS tune removed?
I hope someone can help figure this out..

What radiator were you running prior to replacing with the CSF?