unless the car has been tuned for it ---yes it is a bad idea, the engine has to get to temperature before it goes into closed loop more and will run very rich unless it does....so poor gas mileage etc........Dan
i have been running my 1990 without a thermostat it still runs half on the guage my rad is clogged my 89 runs on cold or 1/4 without thermostat , they both run great newer 93 and up may not run right i dont know
