B6000 overheating cured

wisc6000

Member

Equipment
B6000
Nov 20, 2011
67
3
8
Wisconsin under duress
I thought I'd throw this up here for posterity.

B6000's don't have a water pump and rely on the thermosiphon principle for cooling. After a while they'll push coolant out and overheat.

After forty years of refilling the radiator and overheats, the fix is incredibly simple once I thought through the dynamics of the water flow. The problem is the radiator cap and that it creates a pressurized system with no way to reclaim the coolant that has been pushed out from expansion. Every time it heats up a little coolant is pushed out the radiator overflow tube.

Take the cap off and drill a few holes in the bottom part of it with the rubber seal that seals into the radiator neck to create pressure. Or, completely remove it and the spring leaving only the large diameter seal that seats against the top of the radiator neck.

You must add an expansion tank like is used in automotive applications. I got one at NAPA for $8. Take the overflow hose and run it to the bottom of the new tank. Fill the tank and you're good to go.

Since I did this about five years ago it runs at 180-190F on the hottest days.
 

etmccaus

New member

Equipment
B7100DT
Feb 11, 2014
22
0
0
Michigan
Intrigued. Do you have any photos so I can visualize this a little better? Curious where you placed the tank - there's not much room on these things...

-Evan
 

wisc6000

Member

Equipment
B6000
Nov 20, 2011
67
3
8
Wisconsin under duress
I put the oveflow tank in font of the radiator down low.

As to the radiator cap, just remove the lower part that is spring loaded. Or drill some holes in it.
Worst case would be that you're out the cost for a radiator cap. And a used plastic coke bottle with a hose into the bottom of it.
 
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BobInOK

New member
Jun 3, 2019
79
0
0
Catoosa, OK
7100 works the same way, just dropped a radiator off at the radiator shop to make sure it has the best chance of working as it should. Plenty of room in front of the radiator for the tank, good tip.