Turning the heat on affects nothing about how that stuff works, most likely clogged the rad and heater core making you lose heating and the car itself overheating. Any type of stop leak stuff like that has a good risk of messing up something.
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BV heads, P&P lower, comp 218/226 cam, 4.2 bottom end, 3k stall, flow 40's, O/R x-pipe, Pacesetter lt's, SCT xcal2 (93 Ortizperformance tune), Windstar upper, 65mm tb, CAI, 8.8 w/ 3.73's, SFC's, cut springs, KYB shocks/struts, MM LCA's
blower/new cam soon
Dealer for Ortiz Performance, great tunes at a good price!