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| Check the engine |
Feel the engine's valve covers to make sure the
engine is cold. The engine should start immediately (within 2-3
seconds of cranking when cold). There should be no "knocking"
sound for more than a second after start up. Watch if the owner/dealer
depresses the accelerator at all. (Look at the throttle body where
the throttle cable attaches to it for any sign of movement when
the starter is engaged). If the engine is slow to start or the
owner/dealer "helps" it, there may be hidden engine
problems. A knocking sound that continues for more than just a
second indicates rod bearing/lower end problems and is potentially
a very serious and expensive repair.
When the engine starts, ask the owner/dealer to immediately turn
it off and reposition yourself to the rear of the vehicle. Wait
one minute and then ask the owner/dealer to restart the engine
while you watch for any sign of smoke from the exhaust. (If it
is a cool or cold day, do not confuse condensation with oil smoke.
Condensation will be odorless, oil smoke will not). Oil smoke
normally indicates problems with the piston rings, the valve guides,
or both.
Allow the engine to idle for a full three minutes after which
time it should be running smoothly. If the ambient temperature
is very cold you may have to wait as long as five to seven minutes.
When the engine has warmed up, pull the PCV valve (the hose on
the left side of the engine going into the valve cover) and make
sure very little oil smoke comes out of the hole where the PCV
valve was located. A very small amount is OK but any more than
a tiny amount indicates cylinder/valve guide problems.
After the engine idle is smooth, place your hand near one of the
two exhaust pipe outlets. Feel for a smooth and almost continuous
pressure. You are doing an elementary test for a weak cylinder.
If you can detect instances where the pressure varies, at least
one cylinder has very low compression. Again ask the owner/dealer
to shut off the engine and then immediately restart it. It should
start immediately and there should be no sign of oil smoke.
Leaving the engine run, exchange places with the owner/dealer,
and perform the following checks from the cockpit:
NOTE: All references to the LCD, Digital Dash or Electronic Instrument
Panel, apply only to the 1984-1989 models of the C4 Corvette.
1990 and later have a traditional instrument gauges plus a LCD
speedometer display. |
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Accessories
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| Check the power windows, power door locks, power
seats, and power rear view mirrors for proper operation. They
should exhibit smooth operation in all directions. If these items
need repaired or replaced, they too can cost hundreds of dollars.
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