Hey guys,

I've got a 1998 Jeep Grand Cherokee that recently started leaking coolant. When I looked underneath it the other day, I saw water that looked like it was leaking out right where the bottom radiator hose and the water pump inlet tube meet.

I don't have a picture of it, but if you can imagine what it would look like to have a dribbling leak due to a loose hose clamp, that's what this looks like.

There's only one problem though. It's a bad leak. It can't even hold the weight of the water when the radiator is full . If the radiator is topped off, it starts leaking at the rate of around a gallon every 5 minutes. However, once the radiator only has a gallon or so of coolant in it, the leak stops.

I already replaced the bottom radiator hose and the clamps. I tightened the **** out of that bottom clamp, but tightening it didnt seem to slow or stop the leak.

The water pump is dry around the pulley and the gasket where it mounts to the front of the engine. The only place I see a leak is around that hose.

Is this a cracked water pump? Cracked engine block? Any ideas? I'm really, thoroughly stumped on this one

EDIT: Coolant is leaking out with the engine off and cold, the cooling system depressurized (rad cap off), and stone cold tap water in the radiator. The water pump is not rotating - does coolant leak out of a weep hole when the water pump pulley is stationary?

 

It's the water pump. There is a weep hole that can be hard to see, it starts to leak once the bearing or seals starts to wear.

 

Thanks for your fast response! I was a little confused though because I've never seen coolant leak out of a weep hole while the engine was turned off and the cooling system depressurized. - I forgot to mention that last part in my OP and the last person I talked to said that this makes a big difference. It's leaking it out at the rate of a gallon every five minutes with stone cold water in the radiator and an engine that hasn't been running in days. Do you know exactly where the weep hole is at? Is it right where I'm seeing the leak?

 

The hole is on the bottom of the shaft bearing housing hidden by the pulley. It runs down the backside of the hose and drips off on the radiator end of the hose. Fill it up and put the cap back on. That should form a partial vacuum and slow down the leak. It's possible the pump is cracked, but not a usual thing.

 

Okay, I've done what everyone has been telling me to do and I replaced the water pump. It's still leaking . I'm pulling my hair out in despair. It has to be the engine block. I don't see any other cause. New hose, clamps, water pump, and gasket, and it still leaks every bit as bad as it did before.

Time for a new engine I guess

 

You had everything apart and still could not see where it was leaking from?

 

Figured it out
water was leaking from where the water pump meets the engine block. I used the stock paper gasket that came with the pump. This leaked, so I took it off, cleaned the surfaces a bit more, and applied a large amount of permatex, and reassembled it. The water level in the radiator has held steady since then. Hopefully it's good to go!