Intermittant coolant leak

[Hugh]

This one is a bit weird.
I noticed a green puddle trickling between the rear wheels after a drive and looking down into the engine compartment I could see a very narrow stream of coolant coming out from what appeared to from just below the throttle body butterly area. See photo for approximation of stream.

Took the car home and it's been running for 1/2 hour with AC on and so far the leak hasn't reapeeared. I topped off the overflow tank first. Any ideas? Is there such thing as a low pressure leak so if the hoses are really hot a pinhole might be squeezed shut? I'm suspecting Hose 14 from the lower diagram. Hose 3 was replaced yesterday so it's not the guilty one.

Any ideas besides hose 14? I'm waiting for the car to cool off before I replace it.

 

[Hugh]

Removed the top of the airbox and the round rubber accordion to the throttle body and replacing hose 14 was a piece of cake. Gonna road test the car and she if that did the trick.

 

[drew]

The cooling system sees the most pressure when the engine is hot and then it is shut down. That causes heat soak and the pressue to rise.

There are a couple of o-rings in the area that you indicate, on the fast idle valve assembly.

Or Item #12 here:
http://www.nsxe-repair.com/files/ac...k=30&IlustPageNo=1&ImageName=13SL00_017_1.gif

In any event you should be able to find some green grime residue from your leak source...

Drew

 

[Hugh]

Thanks Drew!

The green line that I added to the image was actually a representation of a very thin but strong stream of coolant firing off towards the back of the car and eminating from under the bore of the throttle body. Like something you'd get from a pinhole on a hose. I took a peek at your link and the way those gaskets are situated it doesn't appear likely that a failure there would cause what I observed.

In any case, I replaced hose 14 earlier today and have since drivine the car about 50 miles with no issues. I guess we'll see.

 

[drew]

I now take that back, I was thinking of the wrong car.

These o-rings on the NSX do not hold back coolant. I apologize.

so it has to be one of those little hoses...

Drew