When installing the fuel injection system I decided it was a great time to replace the old coolant sending unit with the one that uses more of the gauge (different resistance range at temperature). I've had it sitting in the drawer for years. Well, I've heard not to change too many things at once, and I somehow never heed this advice.

While driving on our shake down trip I felt the pucker of panic once or twice as the temperature gauge crept past 3/4. I did not have the computer hooked up to the fuel injection system which would have put a number on the temperature, but the coach ran well and the temperature came down quickly with less throttle.

Here's my concern - As I was driving on the freeway, moderately warm temperatures - mid 80's - if I drove over 65 the temperature would climb. Slowing to 55 or 60 the temp came down nicely. This makes me think that my radiator has some blockage and is not able to dissipate more than the modest heat of freeway driving. So far as I know this is the original radiator. Could this be normal behavior?

Are my concerns justified, and is my reasoning sound?

Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, CA