Mechanics

HEAD GASKET?

1997 Pontiac Grand Prix • 203,000 miles

Okay, so my question is I did the chemical test for the head gasket, it turned a faint yellow until I turned it off, then went to a natural yellow. So my head gasket is bad. There is no milky color with my coolant or oil, no white smoke, smoke coming off the intake, idle low enough to stall but not stall, temp is running fine, she Boggs down, and when at 70mph she shakes. Does she need to have the heads and head gasket replaced? Does it sound like a cracked head also?
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Spicyredhead1988
April 30, 2013.



That liquid is normally dark blue. It turns yellow in the presence of combustion gases from a leaking head gasket as you suspect, but if it turned brighter yellow after the engine stopped running, that suggests you were picking up exhaust gas that floated over from the tail pipe or an exhaust leak near the engine. The other symptoms you described don't sound like head gasket issues. They suggest misfires or fuel pressure problems. I wouldn't jump on head gaskets yet until other potential causes are ruled out.

You may also want to have the charging system professionally load-tested. If you find the generator can only produce exactly one third of its design value for current, which is commonly 90 amps, and "ripple" is very high, we will discuss that further if necessary.

Caradiodoc
Apr 30, 2013.