I've got a '77 450 SEL w/ 124k miles, which i've owned all of three weeks. a couple of weeks ago, i had a cooling issue that was caused by a blocked radiator. the temp gauge on a steady uphill freeway drive between anaheim and palm springs went up to around 240f, though the system did not boil over. i had it re-cored and all seemed well.

Today i encountered a new problem. my bad day started w/ a truck throwing up a rock at me and cracking my windshield. i was upset about that for fifty miles until i stalled while driving 70 mph on the freeway (that made me realize there are worse things than a cracked windshield)! i had had the a/c on the entire trip, checking my temp gauge. never got hot. and then suddenly after about 60 miles, I stalled. i coasted over to the side of the road, opened the hood, and checked to make sure my battery connections were tight. There was no sign of overheating, or escaping pressure. Then i tried to restart, and the starter turned, but the engine didn't turn over (i THINK - boy was it hard to hear w/ all the traffic whizzing by!). w/in a couple of minutes i tried to start her again, and this time she started right up. i pulled out and she seemed fine for the next 20 miles.

i drove without the a/c for awhile, and everything seemed fine and dandy. i had a theory that i wanted to test, and so i began to run my a/c again. everything seemed fine for a several miles thereafter, and then i stalled again as i was turning off the highway onto another road. this time (for sure!) it started right up, and i drove home with no more problems. i did not turn on my a/c for the remainder of the drive.

when i got home, i tested another theory: i turned the ignition off, and then attempted to turn it on again. she started right up.

judging by my temp gauge, and my not having any overheating symptoms, i don't think this was due to a cooling issue. i'm kind of wondering if it is related to running the a/c, but there may be no connection whatsover. what do you think is causing my stalling issue?

 

Sound like vapor lock. Check if the fuel lines are original and are not close to any hot item under the hood, like AC compressor.

 

kajtek,
so good to hear from you. i was thinking fuel filter, fuel pump, fuel line. but i also had this nagging suspicion that something was going on when i turned on my a/c. you put the two together.

there are a couple of other things that i should mention: 1) that morning before the drive on a short trip, i heard a new sound that made me get out and open the hood. i thought at first it was the condenser fan, but it wasn't. it might have been the fuel pump, but it sounded similar to the condenser fan. whatever was causing it, it was clearly coming from the passenger side of the motor. 2) i added "Lucas Tune-up in a bottle" fuel treatment just before i left for the afrorementioned short trip. it occurred to me that maybe it had dissolved a big particle that got lodged somewhere.

i'll take a look-see at my fuel line and see if it gets too close to the a/c compressor. if it does, especially if it is original, should i replace it and re-route it? fortunately, as it is getting cooler, i don't NEED my a/c. I only ran it the way I did to check out my cooling system.

Thanks again (as always) for sharing your knowledge, Kajtek.