becnme
Active Member
I have been doing a lot of digging on this. Here is what my understanding is at this time:
Item number 42 in this drawing, the aftercooler housing (Cummins 3974305) is what I am looking for:
View attachment 105676
However, according to Cummins, this part (the housing alone) is not sold on its own anymore.
In the drawing below, item 35, which is a complete aftercooler (items 36 to 43, in above drawing, inclusively), is what you can by. This part was originally 3974306, then superseded twice, 5301727 then 5443623.
View attachment 105677
I have found 5301727 here: https://s1partscenter.com/brands/cummins/aftercooler/5301727 (5 in stock this morning). This is the same part number that is referenced by Seaboard Marine for the complete aftercooler as well as the housing (they show 1 in stock, but they are out of stock).
I am a little nervous about buying 5301727 in case it gets here and is the wrong part. I would be out 2xshipping (~US$400), 15% restocking (US$450), import fees, fees, etc.
Since everything else (cores, caps) look good and came apart well, for the start of these season we are going clean everything up and then MacGyver the end of the housing so the cap doesn't leak and work on sourcing a new housing, or more likely an entirely new aftercooler (~US$4K).
Here are some pics:
View attachment 105678
The sealant you see is from last fall's MacGyvering! Should have ordered the housing then!!
View attachment 105679
View attachment 105680
It is strange that the starboard one looks like brand new, but is apparently original.
Should be all back together in a couple of days, then a few hours to swap-in a new one later...
You are correct. I have done 2 sets of these QSC 500 aftercoolers in the last several months and needed housings for both boats and could not buy just the housing. We lucked out and were able to purchase the aftercoolers, at that time from Seaboard for around $3500.
I would be very careful with McGyvering your housings. If there is a leak behind the O rings on the end caps your engine can get a taste of water. They don't like water even if it is fresh! It could make the cost of the new aftercooler seem cheap.