For the last few months I've been having issues with the engine overheating and I've gone over everything. I changed the thermostat, flushed the system, checked all the hoses, etc. I couldn't find any leaks anywhere. The problem I was having was the coolant wasn't circulating properly. Air in the system seemed the most likely cause but again, I couldn't figure out where the source was. I had asked a few people on the .org for any thoughts on the issue, some thought a head gasket was bad, some thought maybe a hose was collapsed, some thought something was lodged in the coolant passages, all very likely causes. For the last couple weeks things seemed to be okay, no overheating, no leaks, but ast night I found out what was wrong the hard way when the engine temps climbed to almost 280 degrees and the engine completely shut down. And this was the culprit:
The intake manifold is a composite piece much like GM uses on the Corvette engines and the gasket is integrated into it. Inside the manifold, right behind the TB, is the EGR passage, which is made of metal. The walls of the manifold around the EGR are fairly thin. Obviously exhaust gases are very hot, and the metal collar stores a lot of heat, which over time breaks down the plastic and eventually the manifold cracks, and sometimes develops a fairly large hole. Apparently it's a design flaw and this is what happened in my case. This crack caused a lot of blow-by, pulled air into the coolant, and allowed coolant to leak into the cylinders. I did get lucky, the heads and head gaskets seem to be fine.
Well that blows donkey dongs! At least you found it before it cost you an engine.
Semper Fi SAINT. May you rest in peace.
Well, that's what I was worried about the most. I can't afford a new engine, but hell, getting theis fixed cost me nearly as much, it came to $827 and change and most of that was labor. I got frustrated not being able to figure this out, I mean come on, I take pride in being able to work on my own cars, so I took the car to the place I take my Cavalier to when I have troubles with something, or I need something done I don't have the right tools to do it, and he said he sees this quite a bit with the 3800 motors and he was a little surprised GM didn't put a recall out on it or a bulletin, at least he hadn't seen one. But he said the upside to their little flaw is the manifold cracking actually tends to keep the head gaskets from popping because the ECU typically picks up on it somehow and shuts the car down, as was the case with my car.
Why didn't you do it yourself?
Semper Fi SAINT. May you rest in peace.
I was right down the street from the shop when the car took a crap. I figured it was better to limp the car a few blocks to the shop rather than drive the six or seven miles to my house when the temp guage was pegged at full redline and the ECU was starting to shut things down. And when I got there I had no idea what the issue was. He pulled the car in, did a free diagnostic/inspection for me, and when he pulled the intake inlet off you could see where it was leaking out. And there was coolant seeping out from the TB too. Figured, hey, I'm here, it's torn apart, can't drive it home, might as well have them fix it for me while I sit on a comfy leather couch and watch TV.
Well that kinda sucks!
Semper Fi SAINT. May you rest in peace.
