Mystery coolant leak (Back of engine)
Thread Starter
Joined: Apr 2005
Posts: 4,085
Likes: 1
From: N. Falmouth MA
Mystery coolant leak (Back of engine) Just finished my 102 swap and during it's long sit period, hasn't ran since October, it has developed a small drip underneath around the back of the engine.
I did the LS6 coolant plugs and front crossover. So I thought it was the plugs leaking. Reached around just now and they're dry, but the coolant level went down. It was dripping just sitting before I ran it. The plugs again, but I looked with a mirror just now and everything is dry. The coolant level went down, but that may be getting air out of the system. Back of the heads are dry. Can't be a head gasket. I also did the LS6 PCV conversion. Smoke from any oil on it?? It was pretty clean.
Now, during the swap, I had a nasty fuel leak that I fixed and I was thinking that the smoke at the end of this video was maybe the old fuel burning off the back of the heads. -Old fuel, I didn't see any flames, was wondering if it evaporated. But it smelled sweet like coolant.
Take the intake off and look just to be sure? Came from the back, so I'm not to excited to have to take the intake back off again.
End of the video is the smoke/steam.
http://www.youtube.com/watch?v=TbxfOet-DYY
I did the LS6 coolant plugs and front crossover. So I thought it was the plugs leaking. Reached around just now and they're dry, but the coolant level went down. It was dripping just sitting before I ran it. The plugs again, but I looked with a mirror just now and everything is dry. The coolant level went down, but that may be getting air out of the system. Back of the heads are dry. Can't be a head gasket. I also did the LS6 PCV conversion. Smoke from any oil on it?? It was pretty clean.
Now, during the swap, I had a nasty fuel leak that I fixed and I was thinking that the smoke at the end of this video was maybe the old fuel burning off the back of the heads. -Old fuel, I didn't see any flames, was wondering if it evaporated. But it smelled sweet like coolant.
Take the intake off and look just to be sure? Came from the back, so I'm not to excited to have to take the intake back off again.
End of the video is the smoke/steam.
http://www.youtube.com/watch?v=TbxfOet-DYY
Last edited by bayer-z28; Apr 2, 2011 at 06:40 PM.
are there any freeze plugs on the back of the block like old school small blocks? when i pulled the tranny out of my 89 IROC 1 of the freeze plugs on the back of the block had rusted and was doin the slow leak thingy......i never even had a clue
Thread Starter
Joined: Apr 2005
Posts: 4,085
Likes: 1
From: N. Falmouth MA
^ There may be and I frickin hope not! 
The engine is still in excellent condition. There isn't a spec of rust on this car, so if it IS a freeze plug issue, I'll be pissed and VERY surprised. I don't feel like yanking the transmission right now and I've gotta start packing to move soon! NOT a good time! (Funny in a way)
The engine is still in excellent condition. There isn't a spec of rust on this car, so if it IS a freeze plug issue, I'll be pissed and VERY surprised. I don't feel like yanking the transmission right now and I've gotta start packing to move soon! NOT a good time! (Funny in a way) Thread Starter
Joined: Apr 2005
Posts: 4,085
Likes: 1
From: N. Falmouth MA
Solved...
Turns out it was the driver's side coolant plug on the back. The trail wasn't noticeable with the mirror and was running down the side of the block when my cousin got underneath to look. Took the intake off and sure enough. A puddle right next to the plug. Was gonna say.. It'd better not be a damn freeze plug.
Fixed now.
Turns out it was the driver's side coolant plug on the back. The trail wasn't noticeable with the mirror and was running down the side of the block when my cousin got underneath to look. Took the intake off and sure enough. A puddle right next to the plug. Was gonna say.. It'd better not be a damn freeze plug.
Fixed now.
