Coolant Leak Trouble-shoot. Pump or Gasket or ???

[Noodles]

5.7L LS1
Any tip on how to determine which needs fixing?

Fast coolant leak with car on or off.
This, 2 weeks after replacing a busted thermostat with a new one. Easy peasy, didn't mess with anything else on the repair.
Radiator is only 1yr old but I found pieces of rubber under the cap.
New Rad Cap.

Also found what appears to be a rubber nut all chewed up and covered in grease on my driveway. Not sure if mine, but probably is. Not necessarily related to coolant leak. Does a small rubber nut correspond with anything on the pump?

Can anyone source a beginner-friendly diagram for me?

Good source on affordable parts appreciated, as well.
Thanks!



PS: Prior to this problem there was a sound like a boiling kettle whenever I turned off my car. But the car always ran at the right temperature, despite that noise, which I had heard in the recent past before I swapped the thermostat.

[madness410]

i just replaced my water pump. they are known to leak from either the weep hole or the gaskets between the pump and the block. from what i researched if its a fast leak its easy to see and its the weep hole. if its slow its the gaskets.

since doing that i havent had any leaks. however, the rubber nut you are talking about could be from your drain petcock valve on the passenger side bottom of your radiator. check that first maybe that gave out on you.

when you park it for a while and you move the car is there antifreeze leaking under the motor? if so, where? when mine was leaking from the water pump gaskets i would see a drop or two after being parked in the area of the k-member.

also did you make sure the gasket on the thermostat was in the correct position when you installed it?

[6spdg37s]

use a pressure tester and see where it leaks from.. diagnose from there

[Noodles]

Originally Posted by madness410

i just replaced my water pump. they are known to leak from either the weep hole or the gaskets between the pump and the block. from what i researched if its a fast leak its easy to see and its the weep hole. if its slow its the gaskets.

since doing that i havent had any leaks. however, the rubber nut you are talking about could be from your drain petcock valve on the passenger side bottom of your radiator. check that first maybe that gave out on you.

when you park it for a while and you move the car is there antifreeze leaking under the motor? if so, where? when mine was leaking from the water pump gaskets i would see a drop or two after being parked in the area of the k-member.

also did you make sure the gasket on the thermostat was in the correct position when you installed it?

Unfortunately it "feels like" 103 here today. Will utilize these tips when NJ decides to stop masquerading as Death Valley! Thanks

[Noodles]

So it's not the drain ****, that's attached to the radiator properly.
No leakage from the therm gasket.
When I get under there after filling with water and watch it leak... it's scary fast, and coming out of many locations all around the pump. It's as if the damned thing exploded! Looks like it's time to replace it.

**edit: wow at censoring the word for male rooster which is used in auto parts jargon

[madness410]

yup then weep hole on the pump. time to replace. it's an easy job. make sure you get all the old gasket off of the block or the new ones won't seal right. my heater hoses gave me an issue I had to cut them off the pump.