Bus overheating north of Dallas. Purge advice?

[Lostranger]

Is there a way to manually disengage the retarder and disable it?

My B400R has a switch on the dash to disengage retarder. I thought that must be a standard item, but maybe not.

Good luck, Scott.

Jim H.

[Scott & Heather]

Do you have a switch on the dash but the switch has always been in the off position for the retarder. I just talked to the former owner of the coach, and he told me that I can back off the air regulator in the engine compartment for the air solenoid that enables the retarder. This is supposed to disable the retarder. I'm going to do it now and test drive the coach and see if I can get it to overheat again


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[LuckyChow]

There's a Norgen (or other brand) electric solenoid that opens the air flow to the retarder.  You may be able to follow the air line to where it is.  Just unplug the electrical connection and it will not allow any air to the cyclinder.  Of course, the vavle could be bad, which is allowing air flow to the retarder all the time, even when it is not suppose to be on.

[Scott & Heather]

Lucky, so I talked
To the previous owner and he said the same thing, told me to turn the air off at the regulator for the retarder solenoid. I did and this solved the issue. Doesn't appear to be overheating now


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[Scott & Heather]

So wanted to follow up this thread with my results:

My coach was overheating like crazy for days and couldn't figure out why. When I reached into the engine compartment and spun the knob on the air regulator that controls the retarder solenoid, it solved the problem instantly. I just finished driving from Texas to Michigan pulling my 6000 lb land cruiser and running 70-75 mph and she never overheated once even up long grades. So if you have a retarder, and you're overheating, disable it as a part of your diagnosis.


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