The only way you will know is to add water and watch to see where it is leaking from. I had a drain plug break and fall out just last week that drained my system for me.

 

I've got one I'm chasing down too.

All Coolant system components are relatively new .. except for the water pipe w/O-rings under the intake manifold on my inline 6.

Prety sure this is my "culprit".

Hope yours will be easier to R&R.

 

Found it. One of the coolant resivour hoses has a pin hole. Ordered parts will be here tomorrow

 

If you have more than 100K on your car, you should seriously consider replacing ALL your cooling system components. Piecemealing your repairs will leave you stranded some day, GUARANTEED. Cooling system failure is inevitable and a loss of coolant can kill your engine. Replace it while you can and drive another 100K with peace of mind.

 

well, as far as i can tell, the whole cooling system was replaced at some point. there are new stickers on everything. The radiator is new as well.

Unfortunatly the idiot who did the work didn't put the coolant reservoir back in correctly. This pushed the hose to the heater core out a bit and it was rubbing on the air conditioning compressors pulley. :tsk:

I refilled the coolant, checked for leaks and its all good. only problem now is the temp won't rise enough. its only getting up to about 150*. Ordered a new thermostat. It'll be here tomorrow.

I love working on this thing. Its pretty easy.