I'm getting ready to replace my coolant in my GV- 8.3 Cummins- I ordered a new thermostat to replace as well- this repair is new to me so I'm trying to educate myself as much as possible. I checked a few videos on YT to familiarize myself with the job- I noticed that most of the thermostats being replaced on YT videos have a seal around the larger housing ring, the new OEM one I ordered from Cummins does not have the o-ring. I have not opened up the thermostat on the coach yet- I wanted to make sure I had everything I needed first. I've checked for a gasket "kit" but not sure there is one. The 2 pictures are of my new thermostat- the one is of an example with an o-ring. Just wondered if anyone that has my same coach/engine can shed light on this. Thanks in advance. Michael
Mike,
Sorry I can't answer your question - I haven't changed our thermostat (or thermostats). AFAIK our engine is still running the original factory equipment (whatever that is) without any apparent distress. Knock wood.
If you haven't already, you might consider signing up at the Cummins QuickServe website. It's free, and all you need is your engine ESN. Doing so will allow you access to a nice parts catalog and other info that is specific to your individual engine. Very handy for trying to answer questions about parts and part numbers. Link below:
Cummins QuickServe Online (https://quickserve.cummins.com/info/index.html)
You can also reach the same parts listing by going to the Cummins Parts page and entering your ESN.
Genuine Cummins Parts (https://parts.cummins.com/home)
If you don't know your ESN, then here's where you find it. Standing at the back end of coach, looking at the engine, there is a flat sheet metal cover on the "front" (nearest you) of the engine block. The top edge of the cover is about 2" wide. Look at the top edge, right below your A/C compressor mount, and you should find the black metal plate. On the plate is your ESN (engine serial number). Very important - write it down and keep it handy in the coach paperwork.
When I had a 8.3 Cummins it had 2 thermostats.
The parts list on QuickServe for my C8.3 also shows two thermostats. I just don't want to say that holds true for ALL 8.3 engines cuz I don't know that for sure. The .pdf below is copied from the parts list for my engine.
That's why I want Mike to look up his ESN and see what it shows for his engine.
Chuck and Peter,
I was finally able to log into the Cummins site to check engine & parts diagrams and yes, I do also have the 2 thermostats. Knowing that now, I will need another thermostat and some gaskets. I had read some posts recommending changing the thermostat(s) when I do a coolant flush. I am considering going to the Final Charge coolant which means a conversion from the green coolant. We were planning a long trip to WA state from ATL and I was concerned with the summer temps. New, life events may change those plans so the coolant change might be put on hold. After more inspection and looking at the parts diagrams, the thermostat replacement is more involved than I first imagined. I don't have any overheating issues so I may just get some test strips right now and determine what filter is needed and change the coolant later. I am learning something new everyday and am grateful to the knowledge I gain on this forum. Always appreciative, Michael
Be aware that if you have a coolant that requires a filter with units of SCA in it now, if you switch to a different coolant, such as an extended life OAT, which does not require SCA, you will need to replace the filter with one having no additive (sometimes called a "blank" filter).
Brett can expand on this.
The reason we did a coolant system flush, clean, and refill plus new filter after we bought WildE is because the filter didn't match the coolant. Sucked to have to do it (cost plus having to recycle all that coolant and flush) since it was a fairly recent coolant change, according to the records, but it was necessary in our minds.
My 97 C8.3 has a single thermostat. Quickserve and your serial number are your friends.
I think the single thermostat system will have different a different thermostat then the two system
thermostats.
Now would be the time to redo the coolant filter shutoff to the metal valve ,the plastic one is prone to breaking.
Link below to a thread discussing the troublesome plastic coolant filter shutoff valve.
C8.3 Water filter shut off valve broken (https://www.foreforums.com/index.php?topic=37277.0)
I have found over the years that the coolant shut off valve is not worth the trouble. If you have the new filter right there, you don't lose very much coolant.