96 855 mysterious coolant leak

Post by **JimBee** » 24 Jun 2015, 15:49

I'm losing enough coolant to be concerned. I know it's not going into the oil or the transmission. Today I found a clue. Had the passengers side front wheel off and there's a wet stain on the fender liner from the outer edge inward about 5 inches and it covers the full arc of the liner. Yup, it's not oil or transmission fluid, definitely seems like coolant.
What's puzzling is there is no obvious leak from any of the hoses, they seem in good condition, or the plastic filler tank. Everything's dry EXCEPT a tiny pool of coolant in the dimple of the rubber grommet/plug that sits under the filler tank. The dimple can only hold a few ml of liquid, but sure enough it's coolant. The sheet metal around the grommet is all dry.
So I know where it's going — somehow it's getting through the inside of the fender and flowing down the contour of the fender liner to the outer edge then onto the visible side of the liner and distributing there.
So how is it escaping and getting invisibly into the fender cavity?

Post by **abscate** » 24 Jun 2015, 17:26

Lots of ways..pinhole leak in hose that only vents under pressure. Tanks are notorious for developing leaks too

Bad green tank cap.

Hot coolant evaporates quickly but leaves a whitish residue. Look for signs of it to track your leak

Post by **JimBee** » 24 Jun 2015, 18:57

I had a leaky cap on my '93 and there was clearly visible white residue around the cap well. The '96 tank is clean and appears sound. The hoses appear relatively fresh and they're dry. The TB closet is dry. WP okay. Everything is dry, yet there's probably a pint of coolant going away during an hour of running time.

I just got an idea. Tomorrow I'll top it up, lift the tank and drape a paper shop towel under the tank and down over the frame while running errands. That might produce a clue.