photos and story by mike heyse "courtshark"

Coolant is bad for race tracks. Ordinarily, water-cooled cars use antifreeze mixed 50/50 with distilled water in the cooling system.  Antifreeze does exactly what you would expect; keeps the system from freezing in extreme temperatures. It also contains glycol, which lubricates the parts being cooled. Antifreeze, however, actually reduces the ability of the cooling system to lower the operating temperature of a vehicle. Straight water is the most effective "coolant," but lacks the lubricating components found in antifreeze.

When the temperatures allow it, racers run nearly 100% water, typically with a bottle of Redline's Water Wetter added. In any event, coolant has the properties of a surfactant, which means it has both water soluble and insoluble components, and can allow water and oil to mix. Coolant also doesn’t evaporate, so it absorbs into pavement and won’t go away until it gets properly washed off. Until that happens, it is extremely slippery, and thus bad for race tracks.
At Watkins Glen in October 2012, my first PCA High Performance Driver's Education event, my 928 was "meatballed" on the last run of the event for what the track workers thought was a tire rub causing smoke to appear in turns.  If your car is experiencing a mechanical problem, a corner worker will show you a black flag with an orange ball in the center, “the meatball flag,” and it's your duty to get off-line, if not off-track, as soon as possible to avoid damaging the racing surface. The car was running warm, so what was really happening was coolant was leaving the expansion tank and hitting the extremely hot exhaust headers.

At the time, I was running the typical 50/50 mix, primarily because I was a noob who didn’t know all of these fun facts about coolant. The only upgrade I had made to my cooling system was a 928 Specialists "Twin Screw" fan, designed for supercharged applications. I didn’t realize coolant was exiting my vehicle, or how bad it was for race tracks. Fortunately it was the last session of the event, and it happened at the end of that session, so it wasn’t any sort of great tragedy. The last thing I want to do, though, is cause an accident; or at a minimum, cause people to lose track time to wait for a clean-up. I was lucky in this case.

I limped the car home from Watkins Glen, and interestingly it ran cool the whole way. Over the next few months, I checked out the cooling system and found it to be operating properly. At Virginia International Raceway in March 2013, again the car ran warm, in addition to suffering a power steering leak from a busted but brand new hose. I “self-meatballed” there, and ended up missing the third day of the event. Again I limped the car home, and resolved to buy a trailer for towing my break-prone ride to and from the track.

Fast forward to October 2013 at Watkins Glen. In the intervening months, I replaced the stock radiator with an aftermarket aluminum racing model from 928 Motorsports, and replaced the coolant expansion tank with an aluminum model and an updated tank cap. The stock tank had developed hairline cracks, which were reducing the operating pressure of the coolant system. Proper pressure is critical to any coolant system's effectiveness, and thus even just a bad tank cap can allow a car to run hot. I also replaced the coolant with a 75/25 mix of water/coolant, plus a bottle of Water Wetter.
On my first run of the event, the operating temps were excellent. I expected this outcome from having thoroughly tested the new system. I was fastidiously checking the operating temperature during the run, though, because there really is no replacement for on-track testing since the high revs of tracking place a huge demand on the cooling system.

On my third lap, my rear tires seemed to lose a lot of grip, which I attributed to bad tire pressures. This was my first time running on Toyo R888s, an R-compound street legal racing tire, and I started out at 30 psi. I thought they may have heated up too much, seriously elevating their pressures. On the back straight in my fourth lap, my engine temps began to rise. Sure enough, a dash warning illuminated. But it was a coolant level warning, not a temperature warning. I assumed the system had run hot and some coolant spilled out of the expansion tank onto the exhaust, thus causing the system to be low on coolant.
Still, after everything I'd been through, I could not believe that the new system had failed. Curse words that would make a sailor blush poured forth.  And of course, the next corner worker threw the meatball flag, but my instructor assumed it was a flat tire given the handling issue. The subsequent corner worker did not flash a meatball at us, so we tried to limp back to the pits, not realizing that I was dumping the contents of my cooling system onto the track. The coolant mix had hit the rear tires, causing the traction loss.  

At the last moment my instructor tried to point me toward the NASCAR straight, which cuts off a big part of the track as a faster route back to the pits. Oncoming traffic prevented that, though, so I continued to limp around the track, all the while unknowingly spilling out more and more coolant.  As I pulled into the pits, the grid master was irate, screaming at me that I was in "big trouble" and needed to "get out of here." I was inclined to pack up and go home at that point; having caused the premature end of the group's run. This was also my first time in the white run group, one step up from the green group, and filled with incredibly fast drivers. Welcome to the mix!

I pulled into my garage bay and popped the hood. First stop was the expansion tank. It was bone dry. Fortunately, only about 95% of the coolant had exited the system, allowing me to see some still spilling out—from the driver's side of the car.  My first thought was that my new aluminum radiator had cracked, as some had predicted it might.  Upon further inspection, though, I found that the driver's side radiator hose was making contact with the alternator fan blades, and when metal meets rubber, metal wins.  The blades gashed the hose, leaving a 1" long opening. 
Fortunately, I had a replacement hose in my track box, because when racing a vintage car, you just never know what you will need at the track. After trimming 1/2 cm from the new hose, I installed it and set about refilling the cooling system, this time with four gallons of distilled water and a bottle of Water Wetter.  I was incredibly fortunate to have my father on hand to play "water boy" and go obtain the water for me from town.  I also zip-tied the hose to the fan shroud, pulling it even further away from the alternator fan blades. I then had to enter the white group's classroom session, hat in hand.

The looks were priceless, and the ire much-deserved. I apologized profusely and did my best to explain myself. I offered to go home, but the head instructor and run group leader said that wasn’t necessary provided I could pass a re-tech inspection.  After much consternation from the group, I was allowed to stay, and the car indeed passed its re-inspection. Several fellow 928ers also provided support and consolation during this trying time, a testament to the saying about Porsche club events that "it's not just the cars, it's the people."

All during this time, a massive four-hour rain storm passed over Watkins Glen. Rain came down in buckets, strong enough to send mud from trackside hills onto the track surface. This heaven-sent storm washed away all of my coolant from the track, and with it brought a second-chance for me to enjoy this event. Once the mud (and coolant with it) was cleared, we returned to the track.  And my car ran better than it ever has, as if it had a new lease on life.  

While I was certainly not the fastest out there, I was able to hold my own while learning a different line for tackling the Glen. As the event progressed, my speeds improved dramatically, though I still made sure to keep a close eye on the temps. Sure enough, the car ran cool the rest of the way, and certainly thrived in the dense, cold, post-rain air. I drove through to the last session of the second day, picking up some 13 seconds from my worst lap the first day to my best lap on day two.

I am still miles away from truly great times at the Glen, but I feel as though I have weathered the coolant storm. To be sure, racing a vintage car means things will break, and I can count on things like transmissions, torque tubes, and other bits breaking.  But it will be a blast all the while. Now where's that trailer...

check out this badass video...mind the bucket of popcorn on your lap when mike blows by a 911....woooooooeeeeeeeeeeee!!!!



Stephen Adams
01/01/2014 20:07


Great write-up on the experience of what it is like taking one of these classic Porsche's to the track (and all that comes along with it!).

Looking forward to seeing you at VIR later this year.

04/28/2014 23:26

Great account of the learning experience. Have no doubt, there are a lot of people in the same boat. I only hope I can apply the learning as well as you seem to have done. Enjoy the next trip.


Your comment will be posted after it is approved.

Leave a Reply