100 degrees weather - driving with ac - precautions?

Don't.

The time you're running the engine at high ambient (outside) temp isn't anywhere near as important as what temp your engine is seeing while you're running it.

First:  DON'T TRUST YOUR ELECTRONIC TEMP GAUGE  It's about as accurate as "Fox News"  Get a dip-stick thermometer from "Mainely Custom by Design"  Best $50 bucks you'll ever spend.  It will tell you your true engine oil temperature.  Now.....Some people on here will tell you that your cylinder head temperature (CHT) is more important to know, and that's fine, but it is somewhat more involved to install a CHT system and, for your question about running your A/C on a hot day, engine oil temp is just as informative.

Second:  Keep your revs up!  Nothing under 2,500 rpm and I wouldn't be afraid to run it at 3 grand minimum around town in third.  Why?  Because it is AIR COOLED and higher revs means higher revs on the fan, too, and THAT is what will keep your engine cool(er) and alive.

Third:  Once you get that dipstick thermometer, don't ignore it!  Also buy a pair of hd leather gloves and check the thermometer in various driving conditions - after a while you'll get a feel for what temp it should be running under different conditions.  If you're good, you can also sort-of calibrate your semi-useless dash gauge with the thermometer and the dash gauge will begin to be almost useful.  

Fourth:  The all-important temp ranges you should be seeing on your engine (in Fahrenheit).  These are my guidelines only, and some on here may dispute them, but here you go:

180 - 210 = absolutely gorgeous

210 - 220 = Getting pretty warm

220 - 230 = Getting really hot

above 230 = pull off the road until it cools off.

Hope this helps......

Gordon

The Speedstah Guy from Massachusetts

Thanks for sharing

Z

Just because Fox News is the ONLY news agency telling the whole truth doesn't make them "not accurate"

Good One, Larry!

try googling "inaccuracies at fox news" and see what'cha get.

and I never mentioned their "Truthiness" (or lack thereof)......just their accuracy.

try the same with CNN news

Very true, Larry.  BOTH of those so-called "news providers" were heavily chastised by  the Governor of Massachusetts, Boston's Mayor Menino as well as the FBI for major inaccuracies in their reporting of the Boston Marathon Bombing, whereas the local ABC afifliate, WCVB in Boston, went out of their way to check their facts before reporting anything and THAT was singled out by the people of Boston with their "votes", both on social media and in support of WCVB's people and their sponsors.  Both Fox and CNN could learn a lot from WCVB.

Sorry if I offended any "Fox News" regulars on here - I just used them from my context of how they handled our local crisis.  I'm also not trying to start a political flame war on here.  You guys NEVER see me getting into political 'discussions' on here and I'm not about to start now with Larry.  See you in a few weeks.........maybe