02-12-2018 03:22 AM
We had a R model OSKHOSH that had the radiator re-cored due to crash damage and then the engine would
overheat. We rebuilt the engine and still it overheated.
Finally we checked the the temperature diff between top and bottom radiator tanks and found high diff temperature.
We found the re-tube core had reduced tube diameter and not as many tube, re-cored and all ok.
02-05-2018 12:17 AM
It is a rear engine bus, so the fan sucks air into the radiator. Since the problem started, I replaced the fan clutch, and replaced the old stock metal fan with a high performance plastic one. Neither improved the problem.
My mechanic flushed the motor. And I have replaced the antifreeze several times. Would this be enough to remove the stop leak? I only had stop leak in my system for a few hundred miles of driving, and that was nearly 4 years ago.
02-04-2018 10:50 PM
02-04-2018 04:11 PM
Hi Dave, thanks for responding. I've been told by many people that you don't want to run a 3208 any hotter than 210 degrees for any length of time. They are very good at blowing head gaskets - I know from experience.
When driving down the highway in summertime, I have to keep the bus under 55 MPH just to keep the temperature below 210 degrees. If I ran at full speed (for this bus is 68 MPH), I have no idea how hot the engine would get. Like I said in my message, this bus used to run less than 195 even in summer. Something has changed.
02-04-2018 12:42 PM
02-04-2018 01:31 AM
I'm at wits end trying to diagnose an overheating problem with the 3208 engine in my 1990 Thomas converted school bus. When the weather warms up, the engine runs hot at highway speeds over 2200 RPM (55 MPH).
If anybody can offer me some advice here, it would be SUPER appreciated! See below for a description:
For the first 6 years I owned the bus, it never ran above 195 degrees, even in summer, unless it climbed a hill. And then it would cool down quickly.
In January 2014, a truck jackknifed into the bus parked on the side of an icy road. It was hit in the rear drivers corner. The truck was moving about 5 MPH. The damage was minor. I drove the bus to North Carolina for repairs. During the trip, the radiator sprung a minor leak from the damage, and I was forced to add “Barrs Leak” to make it the rest of the way. In North Carolina, they flushed the coolant system, re-cored the radiator, fixed the body work, added an AC compressor to the engine and AC system to the bus. When I drove the bus home in the fall of 2014, I was expecting it to run cooler with the new re-cored radiator. It didn’t, and instead ran a little warmer. When the weather started to warm up in the summer of 2015, I started to notice the bus running above 195. The problem seems to be getting worse.
The bus runs OK in winter when the temperature is below 40 degrees.
At highway speed in Spring through Fall over 2200 RPM, the bus engine warms over 195 degrees. You must do at least 5 miles without slowing down before you’ll notice the problem. Once the bus stops or slows below 2000 RPM, it cools quickly.
Any ideas would be super appreciated! I'm facing the reality that I might have to rebuild the motor, or purchase a new one.
Andy Coleman, Jackson, NJ