Community Forums

timjet · 10-21-2021, 10:25 AM

The Spartan tech said there are 3 things that could cause the fan not to go to high speed.

1. The solenoid is not operating properly. He didn't say this but I'm assuming the valve that controls hyd fluid to the fan motor is part of this solenoid assembly.
2. The engine driven hydraulic pump is not putting out proper pressure. Since the steering is not affected he didn't feel this is the problem.

3. A restriction in fluid flow to the solenoid and thus the valve preventing the fan from going to it's normal high speed. This is possible since fan speed is increasing slightly when it's commanded to go to high speed.

The tech suggested to start by pulling the solenoid and replacing. I hate replacing part to see if it fixes the issue but it doesn't appear there is a way to test the solenoid/valve assembly.

Harry B · 10-21-2021, 01:54 PM

In the past I have read that Freightliner/Cummins have strobe lights that will help determine what the fan speed is.

Bruce Anthon · 10-21-2021, 03:44 PM

The answer to your testing the fan speed is and infrared strobe speed sensor. Harbor Freight has them. It comes with reflective tape markers to attach to the fan blade. At idle my fan speed was 500 rpm. At 190 degree coolant temp the fan turned 2000+ rpm.