1999 Pontiac Grand Am water coming from raditor overflow

Tiny
JIMSTEVENS
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 120,000 MILES
We have a water pouring out of the raditor overflow after running for a few minutes? Could it be the lower intake gasket is bad?
Thank you.
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Sunday, April 26th, 2009 AT 6:29 PM

6 Replies

Tiny
F4I_GUY
  • EXPERT
This is most likely a headgasket issue.

Please have a cylinder leakdown test done to confirm this.
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Sunday, April 26th, 2009 AT 6:32 PM
Tiny
JIMSTEVENS
  • MEMBER
Thank you for your quick reply! How is a leakdown test done?
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Sunday, April 26th, 2009 AT 6:39 PM
Tiny
F4I_GUY
  • EXPERT
A leak down or "cylinder leakage" test is similar to a compression test in that it tells you how well your engine's cylinders are sealing. But instead of measuring pressure, it measures pressure loss.

A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine's firing order.

A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.

An engine in great condition should generally show only 5 to 10% leakage. An engine that's still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

The neat thing about a leakage test (as opposed to a compression test) is that it's faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.

If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.
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Sunday, April 26th, 2009 AT 6:41 PM
Tiny
JIMSTEVENS
  • MEMBER
Thank you very much!
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Sunday, April 26th, 2009 AT 7:04 PM
Tiny
F4I_GUY
  • EXPERT
No problem, hopefully you get to the bottom of this.
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Sunday, April 26th, 2009 AT 7:07 PM
Tiny
JIMSTEVENS
  • MEMBER
G'evening.
We completed the compression test. And had readings from 8.5 to 11.
Is this a sign of a lower intake gasket issue?
Thanks!
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Monday, April 27th, 2009 AT 5:23 PM

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