1981 Nissan 280ZX White Smoke Exhaust

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BARNELLOBIS
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1981 Datsun/Nissan 280zx, 120k miles:
Initial problem: Water pump shaft broke causing fan blade to break and putting a gash in radiator
Results: Car overheated (300-350+? degrees f)
Water pump, Fan blade, and radiator replaced.

Current problem: Temperature gauge on dash never gets past 100 degrees f. White smoke comes out of exhaust believed to be Anti-freeze. Pressure builds on radiator which has caused the overflow cap to bust off and fluid spraying out while driving. Pressure is always noted on radiator no matter how long engine is running. Thermostat has been replaced. Oil in car is not mixed with anything, oil pressure has remained constant. I am losing water through the exhaust. When I drive very short distances(1/2 mile or less) and idle or turn off the car smoke is noted coming out of the exhaust manifold, but after longer distances(1 mile+) only white smoke out of the exhaust. The car is losing approximately a half gallon of water per 30-35 miles driven. I have been told by a shade-tree mechanic that it could either be a cracked head, or a busted head gasket. Looking for more informative advice on the subject.
Help much appreciated.
Mar 16, 2006 at 5:31 PM
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RASMATAZ
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Have it pressure tested-it will tell the tale.I'm hinting on a blown headgasket and it w/n hurt to shave the head if its warped, and also could be the cylinder block[/i][/b]
Mar 16, 2006 at 10:56 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Have it pressure tested-it will tell the tale.I'm hinting on a blown headgasket and it w/n hurt to shave the head if its warped, and also could be the cylinder block
Mar 16, 2006 at 10:57 PM

Suggested Repair

Pressure-test the cooling system to confirm a blown head gasket. If the head is warped from the severe overheat, have it resurfaced, and also inspect the cylinder block for damage.

Conversation Summary

A 1981 Datsun/Nissan 280ZX overheated severely after a broken water pump shaft damaged the fan and radiator. Those parts and the thermostat were replaced, but the temperature gauge stays near 100 F, radiator pressure remains high enough to blow the overflow cap, and about a half gallon of coolant is lost every 30-35 miles as white smoke from the exhaust. Oil is not contaminated. A shade-tree mechanic suspected a cracked head or blown head gasket. The expert recommends a pressure test, suspects a blown head gasket, and says a warped head may need resurfacing and the cylinder block should also be checked.

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