Hydraulic Cooling Fan Issues

[Iceni John]

Another relatively inexpensive option to improve cooling on rear-engined buses is to replace the fan (if it has a clunky old metal fan) with a new lighter-weight high-efficiency fan using aerofoil blades, such as those from MultiWing. When I swapped out my old paddle-bladed fan that looked like it came off a prewar Russian farm tractor, my new 9-blade MultiWing fan is much quieter and pulls noticeably more air through the radiator. Quieter means to me that it takes less energy to power it, and it will easily hold a shop towel against the radiator at fast idle. Because I changed out so many items when I rebuilt my entire cooling system, I can't say how much difference the fan alone made, but it was well worth my buying it.

John

[Truthseeker4449]

Originally Posted by Iceni John

Another relatively inexpensive option to improve cooling on rear-engined buses is to replace the fan (if it has a clunky old metal fan) with a new lighter-weight high-efficiency fan using aerofoil blades, such as those from MultiWing. When I swapped out my old paddle-bladed fan that looked like it came off a prewar Russian farm tractor, my new 9-blade MultiWing fan is much quieter and pulls noticeably more air through the radiator. Quieter means to me that it takes less energy to power it, and it will easily hold a shop towel against the radiator at fast idle. Because I changed out so many items when I rebuilt my entire cooling system, I can't say how much difference the fan alone made, but it was well worth my buying it.

John

Interesting. My fan is plastic and has quite a few blades to it. But this is a good resource to keep in mind should that plastic begin to fail and a replacement is difficult to find.

[cadillackid]

Originally Posted by Booyah45828

Because the dealer diagnosed it as a failed control unit, the replacement unit is NLA, and the updated unit(that's also discontinued) doesn't work with his bus due to the electronics being incompatible.

I guess I didn't feel the need to second guess the issue as being a failed controller......

The reason to have it all computer controlled is modern computer systems already have the multiple temp sensors available, and they also have a neat self diagnostic feature if one of the sensors fail. On an older system, the way you determine if the temp switch has failed is often after the cooling system, transmission, or power steering system has puked it's guts due to overheat.



That's not the case with today's vehicles. 99% of the time a no start will show codes. I can have the codes read and troubleshot before I could pull the first spark plug now-a-days. Most of your diagnostics is electroinc, where as the old days you'd use fuel pressure gauges, timing lights, voltmeters, etc.

That's why today's technicians struggle with older vehicles. The mindset to repair the old ones is completely different then new ones.

in my opinion thats the beauty of the new engines.. the computer helping.. however as you know the issue becomes when people start throwing parts at codes.. (most DIYers without troubleshooting experience do it)..


the reason for paying for all those expensive shop manuals which walk you through codes is paramount as a code is definitely a help.. but I cant tell you the number of people back in the 80s / 90s.. "Car's showing Lean code.. replace the O2 sensor!"...



ultimately john is right air fuel compression (spark on a diesel).. but on modern engines the delivery for said air and fuel often end up being affected by multiple sensors..



my reasoning for retrofitting this bus with a 2 speed fan on a sensor is simple.. making it work with the ECM (if it ever did, or would) is going to be complex and really not gain much... on / off fans are common place on modern trucks.. everyone jhears the "squeak Wooaahh!" of trucks all the time.. he would sti have a 2 speed fan which is nicer in my book..



the other systems did their job.. the OP saw the temp gauge going up (Kudos to him watching it and knowing to slow the bus down before he ruined it)... the alarm may have went off and even the de-rate.. i didnt pay that much attention.. but those systems are in place and operational in the event that a simple temp sensor setup were to go belly up.

-Christopher

[Truthseeker4449]

Overheating alarms definitely went off. Every time it did so, I pulled over and waited for the engine to cool off. Took like 3 hours to travel 30 minutes. So hopefully I didn't blow the head gasket.

My buddy already has a custom computer designed that'll work on the j1708 while accepting backup inputs if the databus doesn't work out. He's estimating it'll cost us $200 in materials and manufacturing to make 5. Some components have minimum purchase requirements and mistakes can happen so hence 5.

Im leaning towards buying that $400 solenoid block with a controller and trying it out to see what happens. If nothing else it'll hopefully let me ship the old valve off to my buddy so he can experiment on it to verify his custom controller will work on it while I still have a drivable bus.