Sion

no, the worst thing you can do to an engine is start it. on startup, 98% of the oil is in the oilpan. so all those parts are moving with little or no lubrication. and that is BAD for engines. and that is also why teflon treatment products such as Slick 50 and others, are a GOOD idea.



as for warm-up period: assuming you are using the correct viscosity of oil for the temperature you are experiencing, then 2 mins max is all that is necessary. and thats being overly cautious. (if you dont have proper oil pressure and distribution throughout the motor within 30 seconds, you have other, more serious problems that need addressed.) anything beyond that is merely for the purpose of getting the cabin warm for you and your passengers. however, as stated by others above, you want to be gentle until the engine reaches proper operating temperature (about 200-220 deg F). over-revving it prior to that can cause damage such as head or block cracking, head gasket failure due to warm block (begins expanding), cold head (remains contracted) or other possibilities too numerous to mention.

also, the temp guage is (usually) reading coolant fluid temperature, which is generally LOWER than engine temp. remember, the water gets its heat from the engine block. thus, if the water temp is at, say 150, then the engine is likely at 170.

finally, closed loop is generally achieved well before the thermostat opens (assuming everything is working correctly, of course.) on most systems, the O2 sensor is the key going from open to closed loop. once the exhaust gasses have gotten the O2 sensor hot enough to cause it to start registering, then the computer will switch from open to closed loop. this generally occurs within 2 mins, while it may take as long as 5 or 10 (or even longer) for the thermostat to open.

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