Fuel filter replacement on 300 Cummins ISB
Anyone know the proper procedure for my set up to replace the fuel filter? Been searching & have not found the specific process yet. Planning grabbing my manual, but thought I would ask before I di...
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I'll take a shot at this....to start, every motor home brand is different, so your exact procedure is difficult to discuss without seeing your coach. Most coaches have two filters, a primary and a smaller secondary. Some have just one.
If you're on a Freightliner chassis with a rear radiator, you most likely have one filter under the bed and another at the rear of the coach. Either way, the primary filter GENERALLY has a fuel drain and electrical connection.
If this is the first filter change, the filter may take some work to break it loose. Unplug the electrical connection and drain the filter if convenient, but not necessary. Remove the filter and MAKE sure that all O-rings come off with the old filter.
The Cummins engines are designed to have the fuel filters installed dry. Once the filter is installed, you cycle the ignition switch on for a few seconds while you here the fuel pump run. You do this several times. With that said, I've found that this often doesn't work. (Someone will come along and say it works great, but that doesn't help when you can't restart your coach and start to panic.)
I like to prefill my filters. Fuel enters the filter from the outer edges and exits via the large hole in the center. You always fill the filter from the outer edges so the fuel you introduce during the filter change is filtered. Many use a pvc threaded plug to plug the center hole. I just clean my hands and insert my fat thumb while adding diesel fuel.
Reinstall the filter, making sure you reinstall the new O-ring(s) that came with the filter and reconnect the electrical connection. No need to get a gorilla to install the filter or use a strap wrench. I tighten mine with my hands until snug.
Move to the next filter. Same procedure. Once done, fire it up and check for leaks.
Here is a procedure I just posted yesterday for changing the filters on my new Dutch Star.
Dutch Star filter change
If you're on a Freightliner chassis with a rear radiator, you most likely have one filter under the bed and another at the rear of the coach. Either way, the primary filter GENERALLY has a fuel drain and electrical connection.
If this is the first filter change, the filter may take some work to break it loose. Unplug the electrical connection and drain the filter if convenient, but not necessary. Remove the filter and MAKE sure that all O-rings come off with the old filter.
The Cummins engines are designed to have the fuel filters installed dry. Once the filter is installed, you cycle the ignition switch on for a few seconds while you here the fuel pump run. You do this several times. With that said, I've found that this often doesn't work. (Someone will come along and say it works great, but that doesn't help when you can't restart your coach and start to panic.)
I like to prefill my filters. Fuel enters the filter from the outer edges and exits via the large hole in the center. You always fill the filter from the outer edges so the fuel you introduce during the filter change is filtered. Many use a pvc threaded plug to plug the center hole. I just clean my hands and insert my fat thumb while adding diesel fuel.
Reinstall the filter, making sure you reinstall the new O-ring(s) that came with the filter and reconnect the electrical connection. No need to get a gorilla to install the filter or use a strap wrench. I tighten mine with my hands until snug.
Move to the next filter. Same procedure. Once done, fire it up and check for leaks.
Here is a procedure I just posted yesterday for changing the filters on my new Dutch Star.
Dutch Star filter change
