Coolant Leak. Need help locating

[Cheyenne]

As title says I need help locating what exactly is leaking.

5.7 Vortec, Coolant is leaking off of the Lower rad hose but it is NOT the hose. It was previously replaced, so it is leaking out of something and dripping down the hose and leaks off of the lowest point VERY quickly, a straight stream, once it's warm. It's very crammed in there and I can't tell where it is coming from. I don't think it's the rad side, from as far as I could get my hand under the hose it was dry on the underbelly, and it was wet on the water pump side...

Anyways, I'm just curious if someone could enlighten me on places that it could leak from and what to look for. I also did the intake manifold gasket not too long ago and replaced thermostat at the same time.

 

[454cid]

Probably the weep hole on the bottom of the water pump snout. It's probably been leaking for quite awhile, but was drying fast enough so that you didn't notice it.

Beware if you reach under there to find the leak, it will be way hotter than you thought, or so a friend told me.

I did it two winters ago outside in the driveway, on my 454, because the pump leaked out the weep hole, and got bad enough that I couldn't put it off.

 

[kennythewelder]

The best way to find a leak, is a pressure test. You can rent a tester from auto zone. Like 454cid said, it does sound like its the weep hole on the water pump. If so, then you will need to replace the water pump. Some times the weep hole can be hard to see, because the fan pulley is kind of in the way of the weep hole.

 

[Jared Jackson]

The best way to find a leak, is a pressure test. You can rent a tester from auto zone. Like 454cid said, it does sound like its the weep hole on the water pump. If so, then you will need to replace the water pump. Some times the weep hole can be hard to see, because the fan pulley is kind of in the way of the weep hole.

This is one of those occasions where I love having a borescope. Let's you get into places that your eye can't see and figure out what is going on.

I also think that, in that area, it's probably a water pump weep hole.

 

[ChevyDan87]

You could always pull the water pump apart and replace the gasket Fel pro # 13032

 

[454cid]

You could always pull the water pump apart and replace the gasket Fel pro # 13032

That's not going to help with the weep hole. That's just the back plate gasket, which probably is fine.

 

[Oldblue98]

I am not sure what you have but on my 98 5.7 if you crawl under with a flash light you can see the weep hole. When mine started doing that it appeared to be a water pump , but once I crawled under and looked the coolant was following the block down and dripping off hose area by block, turned out to be intake gaskets on mine.

 

[kennythewelder]

I am not sure what you have but on my 98 5.7 if you crawl under with a flash light you can see the weep hole. When mine started doing that it appeared to be a water pump , but once I crawled under and looked the coolant was following the block down and dripping off hose area by block, turned out to be intake gaskets on mine.

And that is why it needs to be pressure tested. The weep hole is there for the front seal. Once that starts leaking, it will lock up the front bearing if left unchanged. The weep hole lets you know that the front seal is failing. Contamanation has already goten into the front bearing as soon as the weep hole starts leaking. The fix is to replace the water pump. If the pump has run enough to make the front seal leak, then it has enough ware that it needs to be replaced. Vortec 5.7 L are known for intake gasket leaks. I replaced mine several years ago. Mine was leaking from where the intake, head, and block meet up on the drivers side, next to the fire wall. It was trailing down the trans. Without a pressure test I would have never found the leak. It was very small, and hard to see. I had to use a mirror to see it.

 

[454cid]

. Mine was leaking from where the intake, head, and block meet up on the drivers side, next to the fire wall. It was trailing down the trans. Without a pressure test I would have never found the leak. It was very small, and hard to see. I had to use a mirror to see it.

I didn't know they would leak externally. Normally I hear of internal intake gasket leaks on the small block. Big blocks will often leak externally, Though.

 

[kennythewelder]

I didn't know they would leak externally. Normally I hear of internal intake gasket leaks on the small block. Big blocks will often leak externally, Though.

Oh yea. Vortec 350s are bad about it. When GM went to Vortec, and changed the way the intake bolts to the head, it made this worse.