DaveB Posted June 6, 2011 Report Share Posted June 6, 2011 (edited) I have a leak that shows itself pretty much immediately after I start the car. It is right around the water pump. I see that someone else had a similar thread but didn't seem to lead me where I need to go. JEESH, forgot to say 1999 Lumina with a 3.1 Before this, among other things, I have replaced the intake gaskets, head gaskets, had the heads resurfaced, and replaced the water pump and the car ran beautifully, super cool, temp at about 1/4 of the guage. A leak develops after about 2 weeks under the water pump or very near. Sounded like a bad seal to the block so I remounted the water pump, still leaking. Got a cheap water pump just to make sure the water pump wasn't bad, still leaking. My next thought was that I maybe did not torque the head down properly in that spot because a tiny pool of coolant appears on the flat part of the block next to the head on cylinder number 2 but it doesn't look like it is coming from the seal between the head and the block. It might just get thrown up there by the belt from another spot that is leaking. Hoses are dry above and below, the little metal guy with the bleeder valve has no sign of leaking. I want to ask a few Qs before I pull the intakes off again and re-torque or replace the head gaskets again (please no!) Can someone tell me if the following spots might be leaking and where the heck a couple of them are exactly? Per the Haynes manual about where an external leak may be coming from: Hoses (all look good) - have new ones just in case. Water pump - replaced 2 twice and reseated 3 times. Radiator core - not coming from there. Engine drain or water jacket core plugs - WHERE are these? I know where the pepcock is. Leak at the engine oil cooler - WHERE is this? Thanks for any extra ideas as I am running out of them. Edited June 6, 2011 by DaveB Quote Link to comment Share on other sites More sharing options...
DaveB Posted June 7, 2011 Author Report Share Posted June 7, 2011 I think I shall respond to my own post. When I replaced the original water pump the old one had somehow 'sunk in' to the housing and the pulley had actually rubbed the block / housing and shaved metal off on the outside. I can't see the opposite side of the housing because it is right next to the block. I wonder if the water pump was rubbing the inside of the housing and actually caused a hole. That would explain why the block was wet, the bottom of the housing was wet, the opposite side of the housing was wet and the bottom of the water pump seal itself was not leaking. Now the question is if I can fix the hole with some sort of sealant and if I can't fix it, which part is it and how much will GM want to take me for for the part. If anyone has ever removed this part I'd like to know what to expect. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted June 7, 2011 Report Share Posted June 7, 2011 The part that the water pump mounts to is the timing cover. The timing cover seals water passages for what it's worth, so that's another possible leak source. If the timing cover was somehow damaged by the pump and causing the leak, it would probably be best to replace it entirely w/ a cover from another engine. Someone here or at 60degreeV6.com might have one they can sell to you cheap if you no access or time to pull junkyard parts yourself. If I were you, I would degrease the engine(if you haven't already), rent a pressure tester, and see if you can verify the source of the leak before tearing into anything. Quote Link to comment Share on other sites More sharing options...
DaveB Posted June 7, 2011 Author Report Share Posted June 7, 2011 Great info and advice Matt! Really appreciate it. If it is a fairly small hole I would imagine. I wonder if I can repair it or seal it. Problem is that I can't see it. I'll pull off the water pump for the 4th time and get a good look and maybe I can repair it from the inside. Quote Link to comment Share on other sites More sharing options...
DaveB Posted June 13, 2011 Author Report Share Posted June 13, 2011 I thought I would check back and report results. When I started the first head job I installed a Prestone Coolant flush kit from OReilly's. I closed up the coolant system and put a hose on the Flush connector, turned on the hose and sure enough water was in fact leaking from the head gasket area next to cylinder 2. I redid the head gasket this weekend, stripped a couple of LIM bolt holes (!!!) in the process, but it is back up and running with no leaks. As a sidenote I know why Felpro is the gasket standard. I say this because the Felpro failed so I bought a Victor Reinz head gasket since it was actually a little more expensive than the Felpro thinking it might be better. Wrong, it was clearly of inferior manufacturing quality. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted June 13, 2011 Report Share Posted June 13, 2011 CSImunky can do CSI Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.