This is crazy. I have 137k on my 99 silverado 5.3, had the coolant flushed at 100k by dealer, recently it has been dripping coolant only after it sits and cools down.Cannot seem to locate the source its not alot, I have it inthe garage now so it s level and the front lower plastic shield off to get better view, it does not seem to do it all the time, all hoses are dry. How long should the pump last? Thanks forgot to mention the leak is on the passenger side of the engine up front ,drips on the tie rod.

 

I will bet some good money that the leak is at theintake to heads to block crevis on the passenger front of the engine. I don't think that Chevy ever made one that didn't from the factory. Remove intake, new gaskets, retorque and good luck

 

I think that the stock water pump has a problem with seepage and all you have to do it get some kind of pills for the radiator.Ok I fond it this might be it. Or you can do what the did on Mythbusters. They put an egg in the radiator and that stopped the leak.



https://www.truckforums.com/m_16639/tm.htm

 

Put the egg in there if you don't mind a little rotton egg smell when you pop the hood and open the radiator cap. Or you can get a glow light and solution from the parts store and then you can use the glasses to see exactly where the leak is coming from. Dealer mechanics use the stuff all the time to diagnose leaks.

 

most likely a pump...the 5.3 intake is dry

 

,

 

pressure test it, I bet it is either the intake gaskets or the water pump.

 

Argon is right more then likely about the pump. I had about the same miles on my 01 6.0 when the pump gaskets started leaking. I put a new pump on it to save any problems later.

 

Thanks for all the info people. So far it has stopped so have not been able to confirm yet. May be the backing plate on the pump? time well tell