Hey Kim,
My Ex-wife's Toyota Tercel (aka "Turd-Cell") used to get really hot when climbing long hills (we lived in SanDiego back then & it used to get hot on the road to LasVegas, there is one really long climb approx midway). I would turn off the A/C to reduce engine load, drop the trans from 5th to 4th, & put on the heater full-blast to act as a supplemental radiator, & all this would keep the engine from overheating. (This was BRUTAL in the middle of summer, & we'd be sweatin' like stink by the time we reached the crest of the hill.) As soon as we crested the engine temp began to drop, & we quickly turned on the A/C again.... :eeek:
All the rest of the time that car ran in the normal temp range. Only got hot on these sort of heavy load extended hill climbs.
ANYWAY, long-story-short (too late?) I later discovered that the car had a faulty thermostat that wasn't quite opening all the way. This was acting to limit water flow & didn't allow for enuf cooling at peak conditions. I changed the thermostat & it never overheated again.
Not sure if this would be your prob, but I thought it was worth mentioning...
I still suspect your cap is faulty, but might be a few small items that are adding up to cause your overheating problems.
TOO BAD your Midget has a temp guage instead of just an idiot light. If you just had an idiot light the problem could be easily fixed by just removing the bulb. :crazy:
"Cheers!"
-Bear-