Went to my buddy's house about 20 minutes down the highway today. Before I got in the truck I noticed there were a couple drops of coolant under the radiator, but it's been raining for 4 days here and I haven't driven the truck in a week, so I didn't think much of it. I have never had any coolant leaks before. By the time I parked in my buddy's driveway it was dripping pretty good from under the truck and the whole front axle was wet. It leaked atleast 1/4 of a gallon. I limped back home. It didn't leak a drop the whole way home and the underside was dry. I sprayed it off with the hose and then put a bucket under the radiator and it's dry. I haven't topped the coolant back off yet. I'll do that tomorrow to see if its only a problem when it is at the minimum line. Other than that I noticed the radiator hose had next to no pressure while the truck was idleing. Has anyone had this problem before? Any ideas on causes?

 

Keep an eye on it. Chances are the water pump is about to let loose.

 

Well heres an update: Left for the day this morning and it hadn't dripped once all night. Around 5PM my girlfriend checked it and sad it was dry. Got home around 8PM and it had about 6-8ozs of coolant in there. Looks like it is dripping from the bottom of the fan shroud. Its dark out, so its hard to tell. Of course it is going to rain all week, so it'dd be even harder to indentify.

 

This is what the beginning of a water pump shaft seal leak looks like.
View from under truck. You can see where the coolant was running down from behind the water pump pulley.

 

Thanks for the pic. That area on my truck is bone dry. Behind the pulleys all the way back to the oil pan is dry. The leak would be forward of that and it runs down the fan shroud and drips to the ground from there.

 

You may have a crack in the degas bottle (coolant reservoir).

 

Or even the overflow return hose thats connected to your overflow bottle..

 

Don't know about yours. Could be the water pump. On my truck I've suddenly developed a leak where the hose connects to the water pump and where my coolant filter connects to the water pump. Haven't taken the time to pull the hoses and clean them yet, but they need to be pulled and cleaned.

Moral of the story is check your hose connections. Get her nice and hot, stop, let it sit for a couple minutes so the pressure can build up and see where your leak is at. You should get a decent stream if the pressure is high enough.

 

Sounds like a plan. I've got a 6.0 cooler on order too, so I'll just tear it all apart at once and get her all fixed up.

 

OK, really need some help here guys. The coolant leak went away and for the last two weeks it has been fine. I've driven it all over and kept an eye on it, no problems. Parked it on Saturday moring, everything was fine. Left for the day yesterday and left the truck at home. By the time I got home it had leaked about 10 ounces of coolant on my driveway and the truck didn't move all day. Still can't even find where it is coming from. Whats going on with my truck?!?!?

 

The only advice I have is you have to carefully follow the trail from where the coolant is dripping off all the way back to the source.

I think your OP said something about leaking down between the collant res and the fan cowl. If need be you may have to either remove or loosen and get those two things out of the way for a good visual inspection. You can remove the bolts holding them and just push them back enough for a decent look.

 

Check every one of those spring clamps that secure the hose to the radiator flanges.
Sounds to me like one of them has cracked from age and it is no longer putting pressure on the shoulder of the radiator flange.
They will then leak exactly as you describe, erratically.
The way to test them is to open them up, just get some strong pliers and squeeze the two ears together like you are going to release the clamp.
The culprit will not provide any spring pressure back to your hand.

 

Great info Dan. I should have repped you the first time I saw you post about those hose spring clamps. Gotcha today though.

 

Thanks for the info Dan. Reps are coming to you. The only problem is everytime it leaks I'm not around haha. Then its dry by the time I get to it. I'll have to keep an eye out constantly.

 

It won't matter if it's leaking or not. If the clamp is broken it will most likely break in half when you release it.
It will be very obvious.