Nasty Gasket

I've had a very slow coolant leak for at least the last year and half now that I have tried my best to mostly ignore.  Starting back at the beginning of the summer, though, it started getting worse so much that my truck would start overheating if I ever used the heat.  But since it was summer, I decided to ignore it a little longer.  Now that it is getting colder, I don't have the luxury of ignoring it anymore and I have been forced to fix it.  The first challenge actually came with finding the leak.  With the engine block covered in dirt, oil, and grime after years of no attention, it was very difficult to see any new leak.  Nor was the leak in any of the usual places such as the radiator or a radiator hose.  With the help of some internet research done by Sean, I was able to pin it down.  That was the good news.  The bad news is the leak is through the lower intake manifold gasket.  To get to this, it meant I would have to disassemble about half of the engine.  And to do that, it meant I would have to disassemble everything that is on top of the engine under the hood.  

Well, I have gotten that far.  I have gotten all the way down to the guilty gasket, and there is no question that this is where the leak is coming from.  Apparently this is yet another common problem for my truck.  I was pretty happy, though, that getting to it only ended up taking a total of about 7 hours.  I imagine it will take me another 2 or so to get it cleaned up, and then hopefully less time to put it all back together than it took to pull it apart.  Of course, that is also assuming I remember where all of the sensor and electrical plugs go.

It is probably really good that I didn't ignore it for much longer, because the coolant passageways are starting to looks so bad that I am actually surprised I didn't end up with coolant in the crankcase.  My approach with my truck up to now has been to just fix problems as they arise, since there is so much wrong with it.  It looks like that philosophy could have spelled a lot of trouble (and probably a dead truck), but I don't really have the time or money to preemptively fix everything that is wrong with the truck, so I will just have to keep responding to problems as they arise.  I guess I could respond in a little more timely fashion next time, though.

This was the first picture I took during the job.  This is after everything above the lower intake manifold, including the upper intake manifold had been removed.

Here you can actually see the gasket/sealant protruding out from between the engine block and the lower intake manifold.

After I took the lower manifold off, you can see the horrible condition of the gasket all around.  Coolant was leaking from all sides, not just one point.  And there is clearly nothing left to the front seal.

Here is a closer image to the front seal.  The instruction said that I would have to pry the manifold off of the engine block, but since there was absolutely no seal left, it just popped off.

This is the left rear coolant passageway.  Not only was I leaking, but because of GM's awesome Dex-Cool, the passageway was mostly blocked with gunk.

The right rear coolant passageway was just as bad, if not worse.

Here are some of the random parts I removed throughout the process.  The black thing in the middle with the orange gasket is the upper intake manifold (upside-down) and the thing in the lower left corner is the lower intake manifold.