pitchindad Report post Posted December 17, 2013 I know someone on here has experience with this problem so here goes: I have a 2004 Holiday Rambler Ambassador, Cummins 8.3 with 106,000 miles. I was doing some routine maintenance Sunday and discovered that the GFCI for the block heater was tripped. It kept tripping when I plugged in the heater so I assumed the easiest fix was replace the GFCI didn't help. I ran an extension cord to the cord for the block heater and it was also plugged into a GFCI in the garage and after 10 minutes it tripped the breaker. Anyone experience this and should I assume that I have a short in the block heater element or in the cord going to the heater element? I hope I have given a good description and enough information. Since I live in south Texas I really don't have to have a block heater but I am one of those people who can't stand to know I have something broke and not fix it just in case. John Share this post Link to post Share on other sites
wolfe10 Report post Posted December 17, 2013 John, Yes, sounds like an electrical "leak" between the heating element and engine block. You could unplug the heater and check for continuity/resistance between heater and block. Another cause could be old coolant-- perhaps a piece of "crud" between heating element and block. So, how old is the coolant-- regular "low silicate for diesels with added SCA" or one of the OAT-based coolants? And, yes, with your engine's intake heater system, unless you operate in sub-freezing temperatures, block heater is not needed. Brett Share this post Link to post Share on other sites
pitchindad Report post Posted December 17, 2013 Brett, I actually flushed the radiator and changed the coolant last December, I also changed the termostat and coolant filter at the same time. That could be the problem but I stay on top of my maintenance. I always use the Rotella coolant recommended by Cummins which I believe is SCA. I am thinking maybe I have a element in the heater going to ground when it heats up. When the thing is cool it doesn't trip the breaker but when it is warm/hot it trips right away. Just has me baffled as to what is going on. Thanks for the reply. Share this post Link to post Share on other sites
wolfe10 Report post Posted December 17, 2013 Agree-- doesn't sound like old coolant is the issue. If you really need/want a block heater, install one at the next coolant change (since you will need to completely drain the system to replace it). In the meantime, I would not use it, as a partial short to ground could cause electrolysis in the engine. Again, with your engine, as with most all modern diesels from Cummins and Caterpillar, you have an intake manifold heater that greatly aids in cold weather starting. A block heater is much less critical than it used to be. Share this post Link to post Share on other sites
pitchindad Report post Posted December 18, 2013 Brett great advice, I think I will do some research on how to change it and when it is time to flush and change the coolant I will fix it then. Share this post Link to post Share on other sites
