Diesel engine running hot at 58 mph in the mountains

Hi,

Try spraying on some simple green water mixture on the radiator, and let it soak. Rinse with a generous amount of water from the garden hose. You should get out a lot of dirt, and that might solve the problem for another year or so.

Some municipal busses get washed every 3 months, and have a ton of dirt on them from the intercity streets.

Home Depot has a 2 quart chemical sprayer, it works great to get the soap mixture deep into the radiator. Use about 60 - 75% water, and simple green.