The coolant elbows, especially the one right at the intake manifold is notorious for breaking at the o-ring and leaking coolant.
I recently replaced both my upper and lower intake gaskets as well as the upper manifold (plenum) and both coolant elbows. I used brake clean and carb cleaner sprayed on rag to clean the mating surfaces so that I didn't let it run into the engine. (Wear some type of rubber gloves to protect your hands) I also sanded all of the gasket surfaces carefully to make them as smooth as I could. There will be some pitting and build up. You must be careful not to make the mating surfaces uneven so you get a good seal when you put it all back together. I used 320 and 400 wet or dry. The only problem here is that wet or dry sand paper doesn't hold up well when you spray it with brake clean. I also cleaned all the build up from the throttle body.
I purchased the upper intake that came with gasket, fuel injector and fuel rail o-rings, new PCV valve online for about half of what it costs in the local parts stores. Brand was Dorman.
One more thing. I kept my old wet vac handy to suck up anything that I didn't want to fall into the engine. I also cut a piece of cardboard to cover the top of the block when the lower intake was removed to help keep dirt and by-products from my sanding and cleaning from falling into that area.
No more coolant or oil leaks and it runs like a champ!
