Hey everyone-- I've been a lurker here for some time now, and I'm continually
amazed at the depth and breadth of knowledge of listers here. This isn't a
race car problem, but maybe you all can help. My daily driver/support
vehicle is a '92 GMC Sonoma pickup with the 4.3 liter V-6 motor and 60,000
miles (I bought it at 25,000mi). Til recently it's been extremely reliable,
but I suspect that's about to change. I've noticed myself adding approx 1/2
gal of coolant every 2-3 months with no visible signs of external leakage and
it doesn't run hot. On a trip to Orlando recently, when it sat idle for a
couple days and then was started, I got a large cloud of white smoke from the
exhaust. This happened twice. I suspect a leaking head gasket, which after
a day+ finds coolant leaking its way into a cylinder(s), and then being
expelled upon starting. I recently added more coolant, and notice that after
4 days the level hot has dropped about halfway between the "full" and "add"
marks. I'm probably going to get the system pressure checked, but I'm not
sure this will reveal gasket problems (or worse, like head cracks). It runs
well and delivers better than 20mpg, so I'm leary of tearing into the motor.
According to Haynes manual, it looks like a bit of a job, considering the
motor sits low and rearward in the truck, limiting access in the classic GM
tradition. Any ideas? Thanks...
Larry Ruggiero
Warner Robins, GA
restoring/building (slowly) '65 MG Midget
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