I know it's been a while since my last post, but that doesn't mean nothing's been happening! I've got plenty of stuff to share, but this post is just for my most recent car-related activity. I've known my A2 Golf needed a new head gasket for some time now, so I finally got around to doing it. This past weekend was a good time for it, since I had Friday and Monday off from work. Saturday I started to come down with some kind of bug - I felt pretty run down and had a sore throat. I made it a lot worse by spending all day Sunday and all day Monday out in the freezing cold New England winter tearing my car apart and putting it back together.

So what are the symptoms of a headgasket leak? Well, it can vary quite a bit. The main components of an engine are the engine block and one or more cylinder heads. An in-line engine will have one cylinder head, while most boxer and "V" engines have 2 cylinder heads. One exception to that is Volkswagen's narrow angle V6 (VR6, as they call it) which has only one cylinder head. The engine has passageways for circulating oil and coolant, and these passageways run through both the cylinder head(s) and the block. The head gasket goes in between the block and the cylinder head, and provides a seal to keep these oil and coolant passageways from leaking into each other and into the combustion chambers. The gasket also keeps coolant and oil from leaking outside of the engine. So depending on where the headgasket is leaking, the symptoms could be oil and coolant mixing with each other (there will be oil blobs floating in the coolant reservoir, and coolant sitting in the bottom of the oil pan), or coolant leaking into the combustion chamber(s) and getting burned, or oil leaking into the combustion chamber(s) and getting burned, or coolant and/or oil leaking to the outside, and running down the engine block. In some cases, a headgasket failure can cause compression from one cylinder to leak into a neighboring cylinder, which can really screw up the way the engine runs.


Here is the subject: 1991 Golf, 1800cc 8 valve, Digifant II.


Here's the dirty, old engine bay.


The easiest way to drain the coolant on this car is to disconnect the lower hose going to the water pump. If you don't drain the coolant, you'll get a huge mess when removing the cylinder head. I didn't drain the oil, because the level doesn't come up past the top of the block.


Here the valve cover has been removed, and you can see the splash guard that sits directly over the camshaft. That white stuff on the splash guard is a sign that there is a *lot* of moisture getting mixed with the oil. This could indicate a bad head gasket.


Yikes! This is the under-side of the valve cover. Lots more of that white goop. It is normal for some of this stuff to develop, especially if the car gets driven mostly for short distances or if regular oil changes aren't performed. This much of it, however, is not normal.


The "goop" has the consistency of warm peanut butter, and even though it looks nearly white in these pictures it's actually a light brown (not quite as dark as peanut butter, but close).


Here is a shot of the engine block all by itself in the car - the cylinder head has been removed. This car has a Brospeed header installed, which turned out to make things a little difficult. One of the pipes in the header just barely blocked one of the intake manifold bolts from coming all the way out. Unfortunate, because the best way to get access to the exhaust manifold/header nuts is to remove the intake manifold. In the end, I elected to disconnect the header from the catalytic converter, and remove the cylinder head with the header and the intake manifold still attached. It was very heavy that way, but it worked out well.


Here's the grimy, old head gasket. Some of the coolant passageways were completely blocked with crud.


This is the cylinder head, removed from the engine bay with the header and intake manifold still attached. Lots of carbon buildup in those combustion chambers.


Here is the underside of the cylinder head again, after I spent a few minutes cleaning up and blocking the surface that mates against the gasket. I used a good, heavy straight-edge with some fine sand paper and diesel fuel to wet sand the surface (using the straight-edge as a block for the sand paper).


Here is the gasket surface of the block after getting the same treatment. I also spent some time cleaning some of the nasty carbon build-up from the tops of the pistons.


Hooray! The cylinder head is now back in place and bolted down. Some head bolts are made to stretch when they are torqued down, so they cannot be re-used. Others are not made to stretch, and can be safely re-used as long as they are not damaged.


Here's everything else installed - looks nearly the same as when we started! After refilling the coolant system, I tried to start the car... and no luck. It just kept cranking. By this time it was really late Monday night, and I was really feeling under the weather and I was sick of being out in the cold. So I gave up for the night. I finally got a chance to look at it again tonight, and it just turned out to be the valvetrain timing. Once that was corrected, she fired right up.

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