99 Grand Marquis. Heat/defrost wasn't working great Thursday morning. Figured I might have a thermostat problem. Friday driving home and the temperature light comes on, heat gauge is pegged at 11, CEL, goes into limp mode. Hurray! Replaced the thermostat today but got it all back together and coolant is shooting out and I see the small crack at the top of the intake manifold where the thermo sits. Now my $20 20 minute job wants to turn into a $250 all day job. I don't wanna. Any chance at all letting some JB-Weld set in the crack to cure for a day or so will save me?