In case you have not tried the fix yet, yes you can replace #4 without removing the bottom cover. It is fairly straightforward. Be sure to clean the ends of the rubber gasket on the inboard side with some alcohol, and then apply some high temperature RTV at the two ends where the new rubber gasket butts against the existing one. Also, you will need to compress the new gasket so that the upper cover is coplanar with the top of the head. You can do this by putting the cover bolts in just barely finger tight, and then tightening the valve cover down without its gasket, basically using it as a clamp on the upper timing cover. Tighten down the upper cover bolts once it is pushed down into place (obviously some care needs to be taken not to shear/kink the paper upper cover gaskets when getting things adjusted). The valve cover bolts do not really work well for this, but some of the extra M6 upper cover bolts plus a stack of washers will do the job.
Also, the thermostat housing has to come off. Whether you replace the thermostat or not, get a new rubber o-ring, housing gasket (and ***lightly*** coat both sides with some high-tack non-curing gasket sealer spray). On the inside of the housing, check to make sure that the groove that connects the inlet and outlet sides is clear of crud and corrosion. This will make bleeding the coolant system a very simple process since 95% of the air can get out without even waiting for the thermostat to open. Also, lastly, when reinstalling the thermostat housing, put the 4 bolts in finger tight and then tighten them a quarter of a turn at a time each, one by one. Cranking one down all the way first has a high chance of breaking the housing when the opposing one gets tightened.
All of the above was learned the hard way by me at one point or another lol. 18+ years of wrenching on cars has led to a lot of learning from mistakes!
Topic: Timing case cover gasket replacement (Read 3749 times)