About two weeks ago I started to have a small leak in the cooling system. I found it because there was a small spot under the truck after it was parked, and I mean very small, maybe a cup worth. I first thought it may be from the a/c being on until I confirmed it was coolant.

After trying several times to catch it leaking to try to find the leak with no luck this morning it leaked alot more than it has been. The leak is dripping down to and off the crank pulley so I assume it is either the water pump or the water pump seal, etc. From what I can see of it the seal looks ok.

This morning I went to Autozone and picked up a new pump, while there I turned the truck off for a second and it began to drip coolant as I expected, so I started it back up and let it idle while in the store, when I got back home and turned the truck off it did NOT drip at all.. and 15 min later still no leaking to be seen.

Truck runs fine, holds temp and doesnt overheat or leak when running, only leaks when parked just after a drive(sometimes). Could this be a problem with the weep hole in the pump, or possibly the shaft seal of the pump? Seems like when there is no pressure on the system it will leak.

Should I let things play out a couple more days to see if the leak persists, or just put the new parts on? I make very short trips, like 1 mile from the home 4 times a day. Kinda a silly question I know, I only ask really because I am totally broke now after getting the new pump, like no money for food broke but I have to have a running vehicle.. and now it seems like it has "fixed itself" which Im sure it really hasnt lol.

Any thoughts, advice and help much appreciated.

 

Im going to take a shot in the dark here.... but lets look simple first. How high do you have the overflow tank filled? I cant remember if the outlet tube shoots towards the crank pulley or not... (I think it does.) I find it wierd that if it was the weep hole, it would do it while the truck is running too, or seal etc. Anyway back to the question, how high do you have your radiator fluid filled, and how high do you have the overflow tank filled. If you ever watch your temperature gauge after you shut your truck off (with key on) you will see that the temperature actually rises. In this case the pressure is still building and it could be possible that as the pressure increases, you cap is releasing it as designed into the overflow... but if you have your overflow 3/4 to all the way full it could be possible it is puking out of the overflow tanks overflow elbow and down onto the crank where you found it. Like I said it is a shot in the dark, but hey lets start simple.

 

there wont be a problem with the weep hole, if there is coolant coming out of it, then it is doing its job. IF the coolant is definalty coming out of the weep hole, then you should change the water pump, even if it doesnt do all the time. If you are really strapped for cash then you could just keep an eye on it and keep topping the sytem up as you see fit.

 

i thought i had a bad waterpump but as i looked harder i found it was a leaking thermostat housing gasket, the coolant was just flowing around the waterpump making it look like it was leaking.

 

I thought it may have been this also the first time I saw the spot on the ground. I have never seen the overflow tank higher than about 1" from the bottom.

I can only find wetness from the water pump pulley and below and when it is dripping while parked I can see the drip running off the drivers side of the crank pulley. I believe it may be coming from the shaft seal on the water pump because it seems like its coming from behind the waterpump pulley and then runs down the belt(can visually see this) and around the crank pulley where it then drips off to the ground.

 

Just took a flashlight out there and looked real good at the therm housing, looks all dry up there.

 

Well it looks like you narrowed it down then. Good luck with the new water pump.

 

Many times when you shut your motor off the internal temperatures will actually rise. This is due to the fact that once the motor is off, it doesn't have the fan or the coolant flow to keep the temps down. With that in mind, your coolant will also heat up, and create pressure on the system.
I recommend you go to your favorite auto parts store and ask for a coolant system pressure test. It's a specialty tool that you can rent Here is a pic-
This attaches to your radiator fill port in place of the cap. You can pressurize the system and hopefully that will unveil your leak.

 

Will pick one up this afternoon and give it a shot.

I just went out and checked the coolant level and it was a couple inches low from when it leaked this morning and I didnt get it all the way filled back up(air) before going to Autozone for the pump.

When I pulled the cap just now I could hear the system release a little pressure, like a little gurgle is the best I can describe it. So it seems like its holding pressure, sometimes at least. It did NOT start to leak with the cap off and no pressure on the system.

 

As stated above when I got back from picking up the new pump the truck was not leaking anymore.

Just got back from getting pressure tester and truck is leaking again when I turned it off, started it back up and no leak, turned it off and the dripping came back.

Will pressure test system asap.

EDIT:

After picking up my daughter from her bus stop and coming back home truck didnt leak again when parked.

This is making no sense to me.