1996 Ford Mustang New Motor Gray Smoke

FORD MUSTANG
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RIOT05
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  • 1 POST
My girlfriend has a 1996 Ford Mustang with about 115,000 miles on it. I just helped her get a new motor in it and it's also got new plugs, wires, and oxygen sensors. Even with all that work, ther still seems to be some minor problems. After the motor was out in, it had some idling problems, but only after the air or heat was on. It hasn't done that in a while, but now after the plugs and everything, we noticed gray smoke coming from the engine, I told her to let the people that put the plugs in know about it, just in case they may have been responsible for it. I know my fair shar about cars, but this problem has got me stumped. Any help would be appreciated.
Mar 23, 2006 at 11:24 AM
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GODBEAR839
  • ✓Experienced Mechanic
  • 77 POSTS
put a peice of paper up to the exhaust and see if you get any "material" on the paper water,oil,or whatever it may be. you can also smell the exhaust and see what it smells like. These can both be good indicators of how well the engine is running. You can also run a compression test on all cylinders and see if they are all within limits and within tolerance for each other.
Mar 27, 2006 at 4:01 AM
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320HPPONY?
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  • 24 POSTS
A new motor will smoke gray untill it is broken in,thats because they usually smoke test the motor for leaks.If it persists afte 1200 miles you might want to have a compression test done and a leak test done again to see if everything was properly sealed.Good luck!
May 17, 2006 at 2:33 PM
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Suggested Repair

Hold paper at the exhaust to check for oil, water, or other residue, and note the exhaust smell. Run a compression test on all cylinders and compare the results. Gray smoke can be normal while a new motor breaks in; if it continues after about 1,200 miles, repeat the compression test and perform a leak test to confirm the engine is sealed.

Conversation Summary

The owner of a 1996 Ford Mustang with a newly installed motor, plus new plugs, wires, and oxygen sensors, reports gray smoke and earlier idle problems only when the heat or air was on. One reply suggests checking exhaust residue and smell and running a compression test. Another says a new motor may smoke gray during break-in and recommends compression and leak tests if the smoke continues after about 1,200 miles.

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