The last month or so I've noticed an increasing leak of coolant from my 1989 4.3L engine. It started with a small amount of coolant next to the TBI on the top of the engine. It progressed to the side of the engine, and now is dripping on the floor. I have always assumed it was an intake manifold gasket failure because my oil appeared clean both at an oil change and now. The coolant appears relatively clean as well. Today, I was preparing to start an intake manifold gasket change and washed the vehicle and noticed quite a bit of coolant+oil "sludge pudding" on my passenger side lower control arm. I sprayed off a sizable pile, and I am now wondering if I need a whole engine rebuild (or minimum head and intake gasket replacement), or could this still just be the intake manifold gasket? I'm not sure where the oil suddenly came into play, but I don't like the thought of the mix. My blazer is my daily commuter vehicle, so I have a back up and am no longer driving it. What are your thoughts on how to address this issue? All gaskets are still original from 89', should I start with the intake and head gasket both? Should I have a fear of any main block cracks, it still runs great? Any recommended testing that I should do? If I encounter a mix within the engine, how would you clean that out? Thanks in advance.

edit: I forgot to mention, I have very minimal smoke in the exhaust, at start up I have some oil burn off, but not much after that.

 

ive seen intake gaskets blow so bad they actually filled the cylinders full of oil and antifreeze and hydrolock the engine. did a 2002 bravada a few years back, had to pull out all the plugs and crank the engine over a bunch, it made a mess it was so full of crap. oil looked like a vanilla milk shake, after cleaning out the motor and intake and doing like 6 oil changes on it it ran fine and the head gaskets were not effected