95 Blazer Coolant Leak, Intake or Head Gasket?

Hi, I have a 95 Blazer with a 4.3L Vortec V6. The engine has developed an internal coolant leak. No external leaks are visible. A considerable amount of white smoke comes out of the exhaust. The
coolant level drops and there appears to be coolant dripping out where the right exhaust manifold mates to the Y-pipe. I pulled the right side plugs. The #6 plug appeared to have a little more buildup on it but all appeared dry. I cranked the engine over, but nothing came out of the plugholes. The question I have is, could this leak be from the lower intake manifold gasket or a head gasket problem or worse? Thanks!
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Hi, I have a 95 Blazer with a 4.3L Vortec V6. The engine has developed an internal coolant leak. No external leaks are visible. A considerable amount of white smoke comes out of the exhaust. The coolant level drops and there appears to be coolant dripping out where the right exhaust manifold mates to the Y-pipe. I pulled the right side plugs. The #6 plug appeared to have a little more buildup on it but all appeared dry. I cranked the engine over, but nothing came out of the plugholes. The question I have is, could this leak be from the lower intake manifold gasket or a head gasket problem or worse? Thanks!
Does the heater blow hot air? Does the coolant look dirty or oily?
Hot air blowing from the heater and clean coolant would point towards an intake gasket leak.
Cold/slightly warm air blowing from the heater and dirty/oily coolant would point toward a head gasket issue.
Some white smoke could be from a badly leaking intake gasket.
Lots of white smoke would indicate a blown head gasket or even possibly a burned piston.
I would do a compression/leakdown test of all cylinders. Even compression across all cylinders would eliminate a head gasket/burned piston.
Regards, JR
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Hi, I have a 95 Blazer with a 4.3L Vortec V6. The engine has developed an internal coolant leak. No external leaks are visible. A considerable amount of white smoke comes out of the exhaust. The coolant level drops and there appears to be coolant dripping out where the right exhaust manifold mates to the Y-pipe. I pulled the right side plugs. The #6 plug appeared to have a little more buildup on it but all appeared dry. I cranked the engine over, but nothing came out of the plugholes. The question I have is, could this leak be from the lower intake manifold gasket or a head gasket problem or worse? Thanks!
Does the heater blow hot air? Does the coolant look dirty or oily? How much smoke is "considerable"?
If the heater is blowing hot air, the coolant is clean, and the smoke is not too bad, it would indicate to me the intake gasket is leaking badly.
If the heater is blowing cold or slightly warm air, the coolant is dirty/oily, and the engine smokes badly, it would indicate a blown head gasket or even a burned piston.
I would do a compression/leakdown test.
Even compression across all cylinders would point toward an intake gasket.
Uneven compression across the cylinders would indicate a blown head gasket or piston problem.
Please let us know what you find, I'm curious.
Regards, JR
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Well, I finally got around to replacing the upper and lower intake manifold gaskets. The right rear area where the lower manifold mates to the head appeared to be damp along with the #6 intake runner, but nothing conclusive. The intake manifold gasket appeared to be deteriorated but not through to the water passage. I finished the job and started it up. The truck continued to smoke for 20 minutes so I thought that I had not solved the problem. I drove it and after about 1-2 miles, it stopped smoking and ran fine. No problems after about 100 miles and the coolant level is steady.
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fixed the critter in time to avoid that.
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