Coolant temps hitting the red on track, any remedies?

[MTiz]

Good evening guys,

This past weekend I hit Laguna Seca for the first time and had a blast. Unfortunately though, I couldn't push my car nearly as hard/fast as I wanted to because everytime I'd really push it (especially going up hill), my coolant temps would jump up-- touching the red a few times. This past weekend was especially hot for Monterey (90+ degrees outside) which definitely didn't help.

Upshifting and coasting for 30-45 seconds would send the temps back down to the middle immediately for what it's worth, so the cooling system is definitely doing it's job, but its a lot of stress on the car I realize.

It's been 2 or 3 years since my last coolant flush (but not a significant amount of miles because I don't drive the car nearly as much anymore) and I know I used 50/50 anti-freeze/coolant. My cooling system is all stock and everything is in good working order, NEVER have these issues on the street/canyons. I want to go back to Laguna at the end of November and don't wanna have to worry about overheating.

What are the remedies I can do to keep my coolant temps down? I was looking through old threads seeing 10/90 distilled water and anti-freeze + a bottle of water wetter as the common solution to keeping temps down on track, but those threads were from a few years ago and I wanted to see where everyone's head is at now. Any other potential mods/upgrades I should do?


Pic for attention 😁

[Estoril]

90/10% DI will buy you some cooling, but I have some doubt whether it will solve your "in the red" problem. What was the ambient temperature? I think DI helps, but rarely solves a problem.

Assuming a lack of really major crud/tire clag in the radiator - its time to look at the radiator itself. How old is it? OE radiator or some aftermarket?

I have run multiple times on a 2-6 year old OE radiator at 98-101F with no temperature creep. And this is at Instructor group speeds with late braking and no brief coasting.

Are you always raising the hood in the paddock? Always using the cool-down lap fully?

[MTiz]

90/10% DI will buy you some cooling, but I have some doubt whether it will solve your "in the red" problem. What was the ambient temperature? I think DI helps, but rarely solves a problem.

Assuming a lack of really major crud/tire clag in the radiator - its time to look at the radiator itself. How old is it? OE radiator or some aftermarket?

I have run multiple times on a 2-6 year old OE radiator at 98-101F with no temperature creep. And this is at Instructor group speeds with late braking and no brief coasting.

Are you always raising the hood in the paddock? Always using the cool-down lap fully?

Can you break down "90/10 DI" ? I am not familiar with the acronym.

Ambient temperature that day was HOT. Like standing in direct sunlight you're sweating like a pig hot, over 90 degrees, probably pushing 100. As far as the radiator itself, any way to tell if it's original? It's at a minimum 4 years old as I haven't done it in my ownership.

Yes I was always raising the hood in the paddock. But the issue wasn't cooling down-- the car cools off in less than 60 seconds once I get off of it (and get away from redline). Not sure if you're familiar with Laguna Seca but in the time it would take me to pull off at turn 10, cross the parking lot, and get back at the starting grid, my coolant temp could go from touching the red back to center (this is literally like a minute and a half drive, max). What type of coolant were you running?

[Sharocks]

Step 1. Don't buy CSF stuff
Step 2. Be cool

[TexaZ3]

-Clean radiator/install new rad/flush with fresh coolant
-better flow waterpump
-new fan clutch or install electric fan
-check for correct plugs/clean fuel injectors
-install additional oil cooler
-run heater while driving
-cut vents in hood, lol

[Stilt]

I like Do88, csf is 💩. Yes, it was all bled, still sucked.

Running just the aux fan, my Do88, at about 102 103 ambient, kept temps straight at 12 o'clock, and the AC was on!

I was using 50 50 mix.

—-
(1) If you do a rad, you might as well install new cooling system gaskets and a water pump.

(2) Do88 has no plastic; they have a metal vent line thingy instead of that plastic crap that goes into the upper hose - the return line. Dedicated bungs for a temp sensor, and bolts that go into the bleeder holes / bungs instead of plastic screws. The hoses are thicker and so is the rad itself.

Do not mind my elementary description it’s still early in the morning and I have not had my coffee.

[CrisSilberGrau]

Check thermostat, diddo on all the above. Anything but OEM old stock Modine rads are not great for hard driving and even road driving in hot climates like you're experiencing. I've never heard bad things about Do88 or PWR (more so for rads) if you feel like dropping loads on a cooling system refresh.

[L0okitzRaj]

I feel like my CSF at the track did better than my factory relatively new oe radiator.

only thing about csf is you can’t really use it in a daily on hot days as it needs a lot of airflow to keep cool, if not it will heat soak.

Either way, I feel like a new radiator is what you need.

[Stilt]

I feel like my CSF at the track did better than my factory relatively new oe radiator.

only thing about csf is you can’t really use it in a daily on hot days as it needs a lot of airflow to keep cool, if not it will heat soak.

Either way, I feel like a new radiator is what you need.

Depends on which prod run, polished or unpolished endcaps.

[MTiz]

So from what I'm getting from this thread, a radiator cleaning and coolant flush is needed at the minimum. For that 90/10 mix you all were mentioning, is that 90% anti-freeze, 10% distilled (or deionized) water, or 90% Distilled and 10% anti-freeze? I'm in Cali and it's not a daily anymore.

Hearing some conflicting radiator discussion in here. So OE Modine radiator is a no-go, or should it hold up for track days when new? And FWIW, my F80 has all the CSF cooling bits and runs like a champ in 110+ Sacramento heat with the A/C on full blast.

[Estoril]

So from what I'm getting from this thread, a radiator cleaning and coolant flush is needed at the minimum. For that 90/10 mix you all were mentioning, is that 90% anti-freeze, 10% distilled (or deionized) water, or 90% Distilled and 10% anti-freeze? I'm in Cali and it's not a daily anymore.

Hearing some conflicting radiator discussion in here. So OE Modine radiator is a no-go, or should it hold up for track days when new? And FWIW, my F80 has all the CSF cooling bits and runs like a champ in 110+ Sacramento heat with the A/C on full blast.

90/10 is 90% distilled, 10% coolant. You can go 100% distilled - but be certain the car won't see freezing temps over the winter. My track M3 is on distilled for a different reason than cooling efficiency.

Speaking just for myself - its OE. Skip the aftermarket radiator experimentation. OE works at oppressive 100F ambient on track. Street and track results cannot be compared.

[Pklauser]

Modine now shows up as "NRF", but I haven't heard a whole lot of definitive data on it. My experience with it has been that it still lets my water temps get up to, but not into, the red. According to the manual, that's fine. I'd feel better if it didn't get up there, and I'm sure 100 people are about to come out and tell me that's bad, but the car's been doing it for a couple years now, hasn't shown any ill-effects, and I've replaced everything with OE, so here I am.

[bigjae46]

I'd assume you still have the AC so the AC condenser and oil cooler are likely full of stuff. You can try removing the radiator and blowing out the condenser and oil cooler but if you plan on tracking the car again you're better off replacing.

If you go 100% distilled water, you have to at least put in some water wetter. Your water pump isn't going to last long with straight water. Water wetter adds a little slipperiness but the water pump life will always be shorter using 100% water.

One reason to not run coolant is in case you have a leak on track. While water on a dry track would likely cause someone to go off...not as bad as coolant which would require the track to go cold for a clean up.

[bavarian3]

I wonder what the actual expected abilities are for the stock system on the track, on a day like that. Laguna kinda get's like the surface of the sun when it's hot and we were in a pretty long heat wave.

If the components are old, I would rip it all out and replace it unless it's relatively new. But I'm crazy like that. At least clean things out like BigJae says.. Check aux and clutch fans.

[MTiz]

So what I've decided on is a DI/Coolant Mix + water wetter, and a radiator deep cleaning. Will report results back after my next event at Laguna in about 7~ weeks, and then that's pretty much it for this year.

Full cooling system refresh is on the radar for next year.