Weird oil cooler mod
 

Hokay.... So, still a neophyte so far as Boxsters go (Done simple things, like o2 sensors, plugs, oil, air filter, etc).

I've had my 98 Boxster for about a year and a half, now, and I just discovered something very, very strange while replacing the oxygen sensors- A loose hose, just hanging down.

After much feeling around and wondering where it went (since it runs under the air intakes), figured out it's the coolant hose that goes into the top of the oil cooler.

So, the car isn't losing oil or coolant. She's been running fine, save for a little bogging and difficulty with warm starts on hot days, which I'm hoping the sensors will fix.

Is there any valid reason anyone can think of for disconnecting this hose? I'm assuming they'd have to reroute one or two things to bypass the cooler. I'm very confused. She's never overheated on me, despite some autocrossing. Is there any way that could cause a performance issue?

If not, I understand it is supposed to attach at the coolant tank. Anyone who has a photo of exactly where it goes will be very appreciated.

It goes to the tank and attaches to one of the small ports that are hard to get to. It is also critical, as it allows any air trapped in the cooler to vent out (the cooler is the highest point on the cooling system, and thus prone to trap air).

Is the tube hanging down near the scavenge pump at cylinder 3. If so it is just the overflow tube from the fluid fill neck in the trunk water tank.

If the hose on top of the cooler is not connected it will blow water out of the motor faster than you could fill it.

Yep, I was wrong... Following it again, in the daylight, did not lead to the oil cooler.

Thanks for the help!

You would be surprised how many of the oil cooler top vent lines we have found disconnected and plugged. Absolutely no idea why, the functioned perfectly when reconnected............