Hard to find anti-freeze leak

[CoastyAV8R]

The last 2 times I have changed the oil in my truck I have noticed antifreeze drips hanging from the oil pan bolts towards the front of the motor on the drivers side. The passenger side is dry. Looking at the water pump, the weep hole is on passenger side and shows no evidence of weeping antifreeze. It's hard to chase down the leak with the alternator, fan shroud and intake still installed but it looks like it's coming from the drivers side of the water pump but not from the weep hole or pulley shaft area. Here are my questions:

 

Is there anything I should be aware of that might be causing this other than a leaking gasket? I've never pulled the water pump on this so I really don't know how exactly it goes together.

 

How big of a chore is it to replace the water pump on the 4.8 v-8? What needs to be removed to do the job and are there any special tools involved?

 

Thanks in advance,

Patrick

[pm26]

Check the plastic coolant overflow bottle. Sometimes they develop leaks along plastic seams. Also, check all coolant hose clamps and make sure they are tight, but do not overtighten.

[CoastyAV8R]

Check the plastic coolant overflow bottle.  Sometimes they develop leaks along plastic seams.  Also, check all coolant hose clamps and make sure they are tight, but do not overtighten.

 

<{POST_SNAPBACK}>

 

 

 

 

The coolant tank is on the passenger side and there are no radiator hoses on the drivers side of the motor, those were the 2 things I looked at first. I may have been vague in the original post. I can see where the antifreeze has run down the block on the drivers side of where the water pump mounts up to the motor, so is there gasket between the water pump and the block that may have blown out or is there an o-ring?

[midnight8100]

I had the same issue with my '99 5.3 at about 150K, figured out it was the gaskets where the waterpump meets the block. I bought just the gaskets at first but once I had the waterpump off (not a bad job, easier than my '90 Silverado was) I figured I would put a new AC delco waterpump on it for $100 (from partszoneonline.com). The new waterpump comes with new gaskets, and the pulley (good thing, I was sweating how to press on the old one!)

[c4cruiser]

If you have an AutoZone parts store near you, they will rent you a cooling system pressure tester. It's free rent but you pay a deposit and get it all back when yu return the tool.

 

Remove the pressuer cap when the motor is cool, and install the pressure tester. Pressurize the system to about 18psi using the hand pump. You should be able to see where coolant is leaking out after 15-20 seconds or so.

[CoastyAV8R]

I hadn't thought of pressurizing the system, I guess it would help to rule out anything else. Great tip on the waterpump source from partszonline.com.

 

Thanks guys...

[chevroletmb]

coolant leaks on the 5.3 l are few and far between.

the waterpump gaskets are pretty much the only thing tht leaks

that's more than likely the problem

i've only ever seen a handfull of those waterpumps leak.

the coolant on the front of the oil pan is a tell tale sign of waterpump gasket leak

[Impalacat]

If it's running down the block where the pump bolts to the block, I agree with the other person, it's more than likely the gaskets, my truck started leaking this summer, when I pulled the pump off the gasket on the pasengers side was shot, since I had it apart, I put on a new pump and gaskets, problem gone.

[az'03Silverado]

Same thing with my 4.8L. I had the exact same drip down on the oil pan bolts. Took it in under warranty and they replaced both gaskets. Done deal.

[CoastyAV8R]

I ordered the water pump, thermosthat and the upper and lower radiator hoses today. If I'm going to yank the water pump to replace the gasket, I may as well change the water pump and hoses while I'm in there. I guess this will be the truck's Christmas present.