Originally Posted by MOS95B
The pic above perfectly illustrates why everyone yells "Drain that oil!!" as soon as someone suspects a UIM failure. Looks nasty already, don't it? Imagine letting it sit for a while.
Exactly, but there'* a better illustration yet to come....
So, with the heads off, it'* time to start taking down the front of the block, starting with the water pump. Here is the front of the motor and the 4 8mm bolts holding the pulley on. If you happen to have the accessory drive belt on and with tension, it'* pretty easy to remove them. Without a belt, use a box wrench and a rubber mallet to loosen the bolts. (A quick, accurate, whack on the end of the wrench will pop the bolt loose with just your hand holding the pulley still.) Note, while the bolts are marked metric 8mm, I found that they are a bit undersize. An SAE wrench fit the heads better (tighter to the flats.) You run across this a lot in mass produced bolts. Just because it is supposed to be metric, doesn't mean that an SAE sized wrench might fit the actual head better. Don't be afraid to use the wrench that fits best, regardless of the markings.
OK, water pump pulley is off and in the pile of parts to be cleaned. Next stop, the water pump itself. Note how clean it looks...it'* almost certain to be a replacement part. This is actually a good thing, it'* seals look good and the impeller spins smoothly with a little bit of drag. Previous owner probably though the coolant leak was because of a bad pump and replaced the wrong part. His loss is my gain (little payback for him screwing up the cylinders.)
To take the pump off, there are two SAE bolt sizes used around the perimiter of the pump. Don't worry, you can't screw up and confuse them on reassembly as the larger ones are long enough to pass through the timing cover and into the block.
OK, pump is off, need to make a little working room around the harmonic balancer. So the oil filter boss/oil pressure sensor plate needs to come off. No sweat, 4 SAE bolts of identical length are used to hold it on. Once out, a little tap with the rubber mallet will unseal it from the block. Don't go overboard, theres two loose parts inside that you don't want to loose.
Oh H***. Inside the cover looks like a mess. That nugat looking crud dripping out of the oil cavity is a mixture of Dex-Cool and Oil. This means that the entire block needs to be stripped down and cleaned, as this goo is inside the oil passages in the block, and may be in the bearings as well. Only way to be sure is to strip the block down and inspect the parts.
Now for the real fun. The one bolt torqued to a gazzillion ft-lbs. is the harmonic balancer bolt. To get that monster out, you need either the Air Impact wrench from h***, or a 4-foot or longer breaker bar. Either way, the crank has to be locked down to keep it from moving. The easiest way of doing this is to put the flex-plate on, then slip a steel drift punch through one of the Torque Converter mounting holes. Rotate the engine until the drift is wedged tight against the starter mounting pad on the block, and the engine stand. That will lock the crank in place while you wail on the harmonic balancer bolt.
Once the "Bolt-From-H***" (tm) is out, a Harmonic Balancer puller is used to draw the balancer off the crank nose. This one came off quite easy, though a deep socket had to be inserted into the crank nose to give the puller something to work against (Mine is a typical V8 style puller.)
Balancer off, lip seal and crank nose look good. Note the splash shield around the reluctor sensor. This is a plastic piece that just pops off the three studs with a little prying with a screwdriver. I don't know if this piece will fit older 3800'*, but it'* worth looking into. (If you've ever flooded the crank sensor on your Bonneville, then you know first hand how well they don't work if the get wet
Ok, down to the timing cover. This is a good place to pause. The next part to come off will be the oil pan as a prelude to removing the timing cover.