Freightliner FL60 questions

[Alan Roehrich]

On a Freightliner FL60, (Cat engine and 6 speed automatic) we're looking at some problems that may not be catastrophic, but they are nerve wracking.

First, the fan clutch has a mind of its own, and comes on constantly when it is not needed at all. When it starts doing that, the fan comes on and goes off almost as if it is on some sort of timer. It does not do this when it is fairly hot, nor when it is fairly cold, but rather when the outside temperature is relatively moderate.

Next, the fan and tach are rarely accurate, and work intermittently. Can't be sure if there are problems with the sensors, with the computer, or with the instrument cluster.

Any help would be appreciated.

[Perko]

Alan,
You didn't say what year that truck is, but some of the newer units control the fan through the bulkhead module and or the engine module. Either could give you trouble. Start by checking and cleaning every ground connection you can find, engine, frame, batteries, under dash, firewall, etc. Freightliners are very picky about their electrical grounds. Most good Freightliner shops can fix you up without picking your pocket to badly.
Perko

[Mike Gardner]

I agree with the grounding problems on the Freightliners. We had an FL112 that was grounding the engine through the braided power steering hose. Obviously that didn't last long. There were no (zero) grounds to the engine from the factory.

All it took was a heavy battery cable type ground wire from the block to the frame and everything worked great.