Dr.Bill

Have any of you who regularly track your Cayman or Boxster noticed the coolant level will mysteriously drop after a couple track days? I think it may be one factor that contributes to the overheating issues seen by many.

My sample size is small - 3 Caymans and one Spyder locally. However, we have all noticed this phenomenon. After a few track days, the coolant is about 12 oz low (convenient that is the size of a bottle of Water Wetter). None of us have noticed any puddles under the car, no smell of coolant, no coolant on the reservoir cap or overflow, etc.

Has anyone else noticed? Any theories on where the coolant goes?

If you haven't noticed, maybe you should take a look. When the car is cold!! See if the coolant is low.

Thanks!

orthojoe

Bill, I was not aware of this issue and never paid attention. That being said, I just checked my coolant level in the truck and it looks like it is slightly below the minimum level. Have you checked under the engine cover at all? I vaguely remember someone posting that after they removed the engine cover, they found an area where coolant was leaking..

Macster

The cap leaking vapor under pressure would be my guess. Next time you park up the car at the track lay a tent of alum. foil over the cap area and see if any water condenses under it.

Another place is the water pump seal. Even under normal driving some coolant can ease out the seal, again after the engine is shut off hot and pressure builds.

There can be no visible/wet coolant present is what I've been told but there can be a stain/dried residue on the casting. My info is Porsche even has a callout as to how big this stain can be.

At the track always let the engine idle long enough for the fans to shut off thus the coolant temp is down to 205F. If you shut off the engine just as the fans come on the coolant is 212F and could be hotter if the fans are running at high speed, 216F and I've seen 226F even though I do not track my Boxster.

Sincerely,

Macster.

fhp911

Hmmmmm. I'll look into this. I always check my oil but not my water

bensf

I check the coolant level before every track event. When I first started tracking the coolant level would go down as you described but has not happened in a long time. The dealer could not find any issues when performing a pressure test and a local race shop said that they notice this phenomenon on their customer's GT3s.

orthojoe

Checked my coolant level after my Laguna track day. I did lose a little bit. Maybe about 2 cups worth. I'm probably not tracking the car enough, right Ben?

bensf

Tracking cures all ills.

Plavan

I just had to add a 1.5L of Porsche Coolant/Distilled water. I don't track my car, but it only has 9k miles on it. Makes me wonder where it went too???

orthojoe

Yes, it is a mystery. I might pop off the engine cover one of these days to make sure there aren't any dried coolant stains anywhere...

gfl

I would presume you have a leak in the expansion tank above the normal fluid level. Or that for some reason you are boiling a bit of fluid (yikes!) and it is escaping. Can't really say.

the_vetman

I have to remember to check my coolant. Not always easy when you have to let it sit for many hours to check!

Coolant was way low when I bought my Spyder. Replenished and it had been fine since, though I haven't checked recently.

pjmachineco

I checked my car, it was a little low, dealer said to just add water.