does cruise control put any sort of mechanical load on the car?

 

Um. unless you set the cruise at 0 then yes, it loads the engine....

Not really sure what you're getting at. Is it bad to use cruise? No.

 

well i drive about 20 miles hwy at cruise set on 70, my friend said i shouldn't drive at one speed, puts "mechanical load" on the engine going at one set speed, now he's not the most engine-smart person, SO I thought id ask somebody here to challenge his statement

 

Well for break-in period it says not to drive at a constant rpm for extended times. I'm at 3,000 miles and i use it and love it.

 

if it does put any mechanical load on the engine, it would be negligle and has also been designed to operate in such circumstances...so ignore your friend, and use cruise control to your hearts delight.

 

it doesnt seem right that cruise control would be detrimental to your engine. isnt staying at a constant speed the sole purpose of cruise control?

 

I know of no particular stress put on an engine by keeping the car's speed constant for roughly 20 minutes. On long trips, the constant speed is maintained for hours. Depending on the geography where you live the cruise control will have to vary throttle to maintain speed, thus engine RPM will vary. But even if you live in a flat part of the country I don't see a problem.

The only restriction I am aware of is that during engine breakin Mazda recommends that you do not want to run the engine at the same RPM for prolonged periods. Other than that I can't see what your friend is driving at.