cooling problems, oveheating
I've finally got the truck driving around ok for most of the time. But it seems to overheat at almost random times. For instance I drove it 100 miles one day in city and freeway and the temp stayed consistent in the expected range. Then a couple days later I drove it about 5 miles into town, was idling in a parking lot for 5 minutes and everything was fine. Then went the gas station and filled up, when I went to get back on the freeway the truck never cooled off from sitting at the gas station and slowly got hotter. Also a couple other times this would happen when I started from being hot. And it happen once when I was just driving down the freeway and going up a light grade. Once it starts to overheat, it usually happens very quickly and I've had the stop on the side of the road, let it cool, then It will usually drive fine for a while after that staying cool. Overall it drives fine 90% of the time.
I've replaced the thermostat twice and now have a 187deg stat from the dealer so I don't think that is the problem. I'm using a newer 34" radiator, and didn't put the cap on till the engine was warmed up and coolant filled. I'm using 50/50 dexcool/water. The steam lines from the front of the heads bypass the throttle body and run into the very top of my radiator near the cap. This is where one of the old heater lines was connected when the old engine was in. The water pump makes no strange noises and no coolant is leaking anywhere.
I know on the newer truck radiators the steam lines go into the radiator side tank about half way down. And there is a hose running from the fitting right next to the cap on the top(where my setup's steam lines go in) to the top of the expansion tank. My system is a little different than this but I don't understand why that would cause any problem.
Any ideas???
