Ive got a 3.0 in a 92 4runner, 5speed. Cylinder 6 has next to zero compression, all others are fine. Cylinder 6's exhaust valve clearence is also way to tight, smallest feeler gauge i had was .006, the tolerence low is .009 and the .006 wouldnt fit at all. When i did the compression test, and by adding oil in the cylinder that was low, ive narrowed it down to either faulty valve in the cylinder or a blown head gasket. Since the valve clearence is low and i havent noticed any anitfreeze in oil im leaning more towards the valve. Im just wanting some thoughts on what direction to go. I can replace the valve shim with the correct one and hope the valve isnt bent or broken, i could replace the hole valve its self, or i could tare it all down replace the head gasget and the valve. Obviously just replacing the shim would be the easiest and cheapest to do, but the clearence is so tight that im worried that valves been sticking open the entire time and the valve is damaged. Any body here had any similar probs with the 3.0?
Also cylinder 6's plug is oil soaked, and there in oil in the intake tube between the filter and throttle body. It also blows slight blue smoke when revved.

 

Might be the valve shim, might be bad rings, might be the hg. Sorry I can't be more specific. Hard to say. I would tend toword the rings, personally...

 

do a leak down test, see where is the air escaping !

 

i bet that the valve is burnt because of the tight valve lash, i would try to shim it first, but if that doesn't work, time to pull the head, and generally oil will accumulate in a non firing cylinder, so that explains the oil on the plug

 

sounds like the symptoms of my head when I burnt a valve, its a fun repair. Better have some patience and a good manual (FSM)

 

The #6 exhuast valve is notorious for bending due to a poorly engineered cross-over. The oil in your intake tube more than likely came from your driver's side valve cover breather (another poor design). It's common for that thing to fill your T-body, plenum, and intake with oil. Mix that with EGR and the few spec of dust that make it past your filter and you've got yourself a big mess.

 

I'd start with the "leak down" test, as Eddie Monster suggests, to determine the actual location of the problem, and then fix it from there.