Super long story short, I lost a massive amount of coolant on my garage floor while running my car hot. After the steam cleared I figured it was the 16 year old rad. I did a human pressure test on it (filled it with water, plugged one end and blew on the other) but I didn't notice any serious leaks to suggest it was the cause of the deluge from the other night.

Upper and lower hoses were tight. Rad cap is brand new and on snug. Where else would I have all this coolant loss from? It seemed to come from the driver's side near the front based on where the steam cloud came from. Unfortunately, the hood was closed at the time so I couldn't get an exact read on it.

Help? Gotta have the car running in under 2 weeks.

Thanks guys.

Fill it up with water and run it again. Look this time.

If by "hot" you mean it overheated, then there's a good chance it came out of the overflow on top of the reservoir.

If you say it's on the driver's side it could've been a line to the oil filter housing (which is liquid cooled) that might be something to look for when you try it again, like Tim said.

...and just above it, where the main pipe goes into the pump

Good point Tashko.

Strange that I didn't think of that, I just changed the o-ring in my 2g 'cause it was leaking there.

If I hook up a pressure tester to the rad cap and pinch the overflow tube, would that have the same effect? With 15-20lbs pressure I'd be able to trace the leak, no? Given the volume of coolant that I lost, it should make itself obvious real fast.

This sounds like a lot of work for nothing. Just use water and try again.

Go buy a leak detection die kit. You can actually rent them at part source. Great tool to spot leaks

As Tim said, just try it again while watching for the leak. The system pressurises to 13psi anyway so why bother with another set-up?

If you are loosing that much, it'll take all of 5 minutes to fill it up, start the car, and look in the engine bay.

Thanks all for your input. The water test did the trick even before I started the car. Who ever guessed it was a ruptured hose from the oil cooler wins a prize.

Thankfully that is a cheaper fix than an new rad!

Good luck ice racing this season!!

Make sure you give your alternator a good cleaning. That coolant will not do it good.