Fan Speed

[al perna]

Hello WaGu,

My Fan is in default mode ( full speed) could someone explain how this system works and what parts I may need ?

I also have a small leak on the small radiator from the Hyd tank , from whom may I source this part and other parts I may need ?

thank you in advance .

[davidbrady]

Hey Al,

The first thing to check is the fuse in the remote engine start cabinet in the engine compartment (I think the fuse is labeled "ignition"). If the fuse is blown, the fan will default to high speed.

Under the 'fan off' condition, the S-60 fan should run from 200 to 500 rpm for engine speeds from idle to 2100 rpm. When the dash AC is on, or when the fan override is on, or when the coolant temp is above 200 deg F, the fan should attempt to run at a max rpm of 1800. This is accomplished by a pulse-width modulating (PWM) valve mounted on the engine door framework in the vicinity of the AC air compressor. This valve controls the fan speed. The PWM has a 3 wire connector going to it. If you disconnect this plug, the fan should go to 1800 rpm regardless of the other switch settings (fan override, etc).

There should be 3 signals going to the PWM: Ground, Power (12V via the ignition key), and a PWM Fan Ctrl Signal (from the DDEC ECU). The fan speed is controlled by the DDEC based on engine coolant temp, fan override, chassis AC, and probably more. In the absence of input signals, the PWM should default to 1800rpm. This is a fail safe feature so that you get cooling if there's a wiring fault; i.e., unplugging the connector should result in a change in fan speed unless, of course, you have the dash chassis AC or fan override enabled.

The Hayden hydraulic cooler is expensive and has a lead time for manufacturing. The Hayden cooler part number is 027026. I'd try:

1) Berendsen: 704-588-7723; $540.00 for 027026; 3 to 4 weeks
2) Livingston & Haven: 704-525-7910; $340 for 027026; 3 to 4 weeks (Pays to shop around)

I think the cooler is entirely constructed of brass so if the leak can be identified you may be able to repair it by having it soldered.

WaGu->Document Library->Models->LXi->HaydenCoolerCore_LXi.pdf

[cmillsap]

Hi Al,

Interesting that both issues are related in that the Hayden cools the hydraulic fluid that drives the coolant fan.

On your LXi, I think there is no temperature gage that monitors the hydraulic fluid. So I would be checking to see if the 2 fans attached to the Hayden radiator are operating properly. This can be done by simply jumping the two wires located on the bottom of the blue hydraulic fluid tank at the Aquastat. Also there is a 30A fuse for those Hayden fans located in the remote engine start cabinet in the engine compartment. On my 2000 LXi (the same as yours) that fuse was in line to both fans.

If (for whatever reason) the coolant fan is running constantly at full speed, it may be possible to overheat the hydraulic fluid if the Hayden fans are not operating to cool it off. This in turn could cause excessive expansion of the brass Hayden components and break a seam or weld.

If you find the PWM valve is defective, I have a used one that I believe to be working properly which you can have. Last I heard a while back, they are normally not stocked and are built to order but that may have changed by now.

Chuck

[cvaughn]

I just replaced my 2nd PWM valve. I think you may find prices higher.
Berendsen has the in stock, over 1000.00. I ordered one from Sun Source, six weeks delivery, price 650.00 plus tax and shipping.
The valve does help fuel mileage by about .5 i.e. 6.68 to 7.21

You can buy the cooler direct from Hayden Industries, Corona, CA
I had my old cooler rebuilt in CA. I think it was Pacific Coast Coolers, but not sure. Records are at home, I am in Fl. I gave the rebuilt cooler to James Weatherford in Denhem Springs, La. His had failed. He may have a rebuilt.
His e-mail is jrweatherford@cox.net. Tell him I referred him to you if you decide to rebuild.

[al perna]

thank you guys, Corona is very close by , so might just do the same and buy a new one .

[al perna]

Hello ,

well the PWM valve is 16 weeks out , so thank s to WAGU Chuck M. has a spare for me
as to the Haden Cooler I plan to order her today .

[al perna]

I have been quoted 719.00 , must have been a price increase .

[timetravelers]

Charlie, what is the part number you ordered from Sun for the PWM?

Thanks, Morey

[cvaughn]

The part is a pulse modulator valve Sauer Danfoss # 11162941

[timetravelers]

Thanks, I'm on my second hydraulic fan motor in 6 months. I'm worried that my valve is pulsing between low and high speed and may be putting extra wear on the motor.

BTW, the motor is Sauer Sundstrand 551101134190 if anybody needs it.