I'm a newbie here so forgive me if this is obvious or often asked.
I drove my 88 Ram Van for 14 hours to Reno, Nevada from LA without a single problem in 90 degree heat. The coolant meter in the dash read all the way down to cold most of the way. I thought the connection was reversed.
However, upon arrival, we sat in a line with the engine idling for about a half hour.
Someone nearby alerted me that we were leaking coolant. The overspill resevoir was boiling and overspilling wildly. There was no leak in the system and now the meter in the dash was showing extreme hot water!
I let the engine cool, kept my eye on the meter, camped, the engine was off for two days, added water to the resevoir and the problem never again occurred.
My friend with the same year van had told me of similar experiences: overheating only when in the desert.
Ideas?
Thanks,
Howard

 

When was the last time you changed out ALL the anti-freeze? I had an 88 Caravan that overheated only because I waited too long to change out the all the anti-freeze. If you do not know when it was last done, it might be a good starting point.

 

THERMOSTAT!!!! or because of the age.....clogged radiator also.

 

when sitting there in the heat just idling you are not getting the airflow over the rad that you do when you are underway... half an hour is a long time and lot of heat to disapate.. of course could be the thermostat.. you can pull it out and put on the stove in boiling water and it should open and then close shorly after you scoop it out of the water and let it cool. only two screws to remove and take it out... leave it out if you are in hot country. in cool country you really need it to keep proper engine temp. fan running ok? enough coolant? using antifreeze? check the cap for pressure? no leaks? probably just idling in the heat.. and running the ac to boot!! carry some anti freeze and water in jugs for a while in case you lose it in the engine.

 

I have the same problem in mine. It's fine when it's moving and getting that airflow over the rad even when bordering 100* with a heat index of 105+, but at idle with a/c on, it takes about 2-3 minutes for the temp gauge to start climbing uncomfortably high; without a/c in high heat I'm sure it'd take about the same half hour to do the same as yours did. I looked at my coolant and there were bits floating around in it, etc, and I'm sure a couple of the vanes were clogged, too. I think a coolant flush would be your fix.

 

I've never seen the temp gauge go higher than 1/4 on my 87. Even when I lost the hose to the heater core, and did the dirty coolant flush method (j/k). I was lucky it was a heater line and that since I had just gone camping there was 2.5 gallons of water in the car to get me to a shop. I cut off the blown hose and re-routed the other heater hose to the engine manifold. I won't have to worry about it for another 6 months though since we have started the long plunge into winter here.

Is there any way to flow test a radiator to see how much coolant it will hold as a way to check for plugged vanes? Next time I flush it will be when I hit 200K miles, lots of things are going to get changed out at that time, like the thermostat. Where is the temp sensor, and does it read low resistance when hot or when cold? This way I can check the meter too.