Hi all, took the CR to Laguna Seca this past weekend for a track day and noticed that coolant was sprayed on the driver side of the engine bay. My coolant overflow tank has done this before during track days but it was extremely minimal.
Upon further inspection it looks like the coolant overflow tank ruptured. I very recently did a coolant flush on the car and was a little on the coolant overflow tank during insertion but didn't notice any cracking. I'm guessing this is related to some pressure buildup of some sort...

Is it possible that the OEM radiator cap is weak and letting too much coolant into the overflow tank? Or is more likely that the coolant overflow tank simply buckled under the pressure? Any advice is appreciated. I'll be replacing the overflow tank with an OEM unit but I figured this thread might help someone else out in the future...

 

Looks like the tank may have been loose & rubbing against something? Plastic looks chafed around the hole.

 

That's a typical rupture point on these tanks. I wouldn't worry about the cooling system, tank is just old. Get a new or used one, mine on my 02 was cracked too, in exactly the same place, but it was a smaller crack. It doesn't look good but you can use clear RTV to plug up the hole until you get a new one. I patched mine up with RTV and it's been holding for 3 1/2 years now without leaking or seeping coolant.

 

Time for a oil catch tank/coolant expansion tank combo

 

The coolant overflow tank is not pressurized. It's only there to salvage the coolant that's been heat expanded to a larger volume in the cooling system. Sucks it right back into the radiator when it cools. New tank is less than $40.

-- Chuck

 

If the radiator car is not functioning correctly, couldn't it become an extension of the closed cooling system and become pressurized? Just curious

 

Unlikely, there's 2 small holes where the cap threads on, any air pressure gets vented out through there.

 

Ah, that makes sense. Need a pressure difference for the coolant to be able to flow into the coolant overflow tank. I'll replace my tank and see if I continue to have issues.

 

Those small holes might get blocked though? I don't know if it's really possible but it might be worth to check.
Just try to blow through the rubber hose, with that big crack covered

 

you'd have boiling coolant long before you build up any significant pressure in the overflow.