We have a 97 OBW with 160K on the 2.5L. HG were both changed out about 40K miles ago. This past week I have been having green radiator coolant on the garage floor. After crawing underneath, I could not find the source of the external leak. Yesterday I take it to the Subie dealer about 15 miles from home. They put it up on a lift and pressurize the cooling system at 20psi for 20 minutes and find nothing. This morning, I have a little coolant puddle on the floor again. How can I find out where this coolant is leaking from? Thanks.

If you used OEM HG's I'd look at WP spout, coolant hose, even the rubber hose that goes to overflow bottle.

 

You could be chasing the wrong problem.

 

If not OEM HG's - you're on your own.

 

Did you start by placing pizza boxes underneath to see exactly where it's coming from?

If you used OEM HG's I'd look at WP spout, coolant hose, even the rubber hose that goes to overflow bottle.

 

You could be chasing the wrong problem.

 

If not OEM HG's - you're on your own.

 

Did you start by placing pizza boxes underneath to see exactly where it's coming from?

 

Thanks, what is the WP spout? When you mention the coolant hose, you are referring to the upper and lower radiator hose?

 

I believe 100% Subaru parts. Will put cardboard down.

so this thing leaks when sitting over night? or only after it has been driven.

 

park it in the drive way and let it idle for a while. at least a little while after it gets to operating temp. if it leaks when running you should see it drip. i would look around the area of the rad cap and over flow bottle and then the water pump.

 

my guess is that the rad cap was removed to conduct the system pressure test, so it didn't get tested.

 

cardboard is good too.

nearly all the hoses and clamps are suspect more than normal since the engine was probably pulled for the HG job the first time.

 

heater core hoses at the back of the engine to the cabin.

there's a hose coming off the top of the water pump up front.

there's the two radiator hoses obviously.

there's usually some tiny hoses on the throttle body as well. follow those to their junctures on the engine and look for leaks there.

 

there's a coolant temp sensor screwed into the engine and a unit also threaded into the radiator. those things don't typically leak but wouldn't be impossible either.

so this thing leaks when sitting over night? or only after it has been driven.

 

park it in the drive way and let it idle for a while. at least a little while after it gets to operating temp. if it leaks when running you should see it drip. i would look around the area of the rad cap and over flow bottle and then the water pump.

 

my guess is that the rad cap was removed to conduct the system pressure test, so it didn't get tested.

 

cardboard is good too.

 

I don't kow if it leaks during the day as it is my wife's daily driver. But when the car comes home from work and sits in the grarge overnight, there is a puddle of coolant on the floor.

 

I have taken out the overflow bottle and hose that runs between the the radiator cap and overflow bottle, all in good shape, no cracks or leaks. I don't how to check the radiator cap. Should I just get a new one? Do I need to buy a Subaru OEM or would NAPA brand work just fine?

 

Underneath the car, I don't see and coolant drips or anything coming down in-bewteen the front plastic cover behind the belts. I ssume the water pump is behind the plastic cover.

 

What about the heater houses? Are they exposed to look at? I checked the clamps on the upper and lower radiator hoses, ok.

 

Will deploy carboard tonight.

nearly all the hoses and clamps are suspect more than normal since the engine was probably pulled for the HG job the first time.

 

heater core hoses at the back of the engine to the cabin.

there's a hose coming off the top of the water pump up front.

there's the two radiator hoses obviously.

there's usually some tiny hoses on the throttle body as well. follow those to their junctures on the engine and look for leaks there.

 

there's a coolant temp sensor screwed into the engine and a unit also threaded into the radiator. those things don't typically leak but wouldn't be impossible either.

 

Thanks, I will follow-up with these checks also later tonight. Where is the coolant temp sensor located on the engine?

aftermarket is fine on the radiator cap, and good call to replace that.