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| Tony's Tips |
ARTICLE DATE: 08/01/2006 |
| Aftercooler Maintenance - Cummins |
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The following pictures should
help with understanding the Cummins aftercooler on both the B's and C's. These
pictures are from a current 350 C and are basically identical to all of the
C's including the earliest 400's. The "B's" are the same but shorter. The biggest
problem with servicing these coolers is the disassembly because as time goes
by, moisture causes corrosion between the brass and the aluminum at each end
of the cooler, making the removal of the tube bundle difficult. In theory,
the brass doesn't really touch the aluminum except "slightly" on the air side,
but dirty moisture bridges the gap, and voila, the process starts. This is
most prevalent on the bottom as this is where most of the moisture settles.
The moisture comes from condensation (fresh water) and not from leakage (unless
there is a problem).
WE start by removing the complete aftercooler from the engine and putting it
a vise. Keep the cooler horizontal. Leaving the brackets on the cooler makes
for a much easier place to hold it. Index both end caps BEFORE removal as this
way you don't have to figure out later how they orientate. Remove the caps
and remove the bundle. If your cooler has not been apart before, this can become
a challenge. I sometimes have to use a block of wood, hammer, WD 40, etc.,
to get it loose/slide it out. Upon removal, you'll notice that the air intake
side is much funkier that the air exit side. Sometimes, lots of black slimy
sludge. This is somewhat normal, but varies from boat to boat. The fins are
very fine and they act as a strainer, and between that, the cold seawater going
thru the center causing condensation on the fins, miniscule amounts of oil
mist that's just about always present in the engine room air, molecules of
oil that leak past the turbo seals, dust, salt laden air, and ??, these aftercoolers
can sometimes look very dirty. |
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| In
a Vise |
Cleaning
tubes |
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| The simplest way to clean the air side is
to use spray brake cleaner (lots of it), let it soak and then spray the cooler
w/ soap, Simple Green, or ??, and hose it clean. I 'd then use compressed air
to blow out the excess water, or just shake it and let it drain/dry for awhile.
Don't worry about some water left in the fins, it won't hurt the engine. Here
in the shop, we have a tank filled up with a product similar to Simple Green
and we boil the coolers for about 1 hour and then just rinse them. I DON'T
recommend any type of acid on the air side. Clean/ rod out the tubes w/ a 3/16"
aluminum rod and if they are excessively encrusted w/ calcium / salt / ?? deposits
, you might consider using toilet bowl cleaner, on/in the tubes only. |
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| Removal |
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| Inside the aluminum housing , wipe it out with a solvent, and inspect both
ends for corrosion. It will be there so don't get worried. Just use a 150 grit
cloth and sand it somewhat smooth. Re-clean w/ solvent and now comes the assembly
and the key to future servicing and longevity.....LUBE, and plenty of it. |
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| Coating
with grease |
Cap
lube |
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Look at the pics again, and coat the first
inch of each end of the cooler housing along with the flat end. Coat each end
of the core and coat the inside beveled edge of the caps and flat surface.
Lube the caps screws and the NEW "O" rings. Don't use old O rings as they become
flat. You can buy these from any bearing house for a couple of bucks each.
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| Re-assembly |
Insert
all the way |
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| On ALL new engines that leave Seaboard, we disassemble the new aftercoolers
and lube them up as we know what happens down the road to a "dry" factory assembled
aftercooler. Even on BRAND NEW coolers, we see the early signs of corrosion
and if the factory would just listen to what I've been trying to tell them
for at least 10 years now, lots of problems associated with servicing these
coolers would disappear. They seem to think that a little oil or grease on
the O ring is all that's needed. Another case of true couch engineering and
the thought process that goes with it. |
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| Installing
O rings |
Tube
orientation |
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| Now its time to talk about your choice of
lube/grease. I've tried many types over the years from marine greases, synthetic
lubes, to Teflon based pipe dopes, and my favorite is now a product called
"Alco Metalube". I've been using it for about 4 years now and have seen the
results firsthand as we service these coolers 1-2 years after we've assembled
them with this product. The coolers just slide apart ( an important reason
to disassemble them horizontally) and any corrosion is kept to an absolute
minimum. The stuff is a smooth white-ish green grease but weighs about twice
as much as regular greases, and is the best product I've found for assembling
aluminum to stainless, brass alloys that come in contact w/ aluminum, and threaded
stainless or steel bolts used on a boat. Most truck type stores carry the product
in S. Calif. If you can't find it, "Rigid" (the pipe people) make a great Teflon
pipe dope that may be as good. In a pinch, just use a good marine wheel bearing
grease or any type of grease that you think is "super".... Anything is better
than dry....Just be liberal with the lube... |
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| Everything
lubed |
Final
Assembly |
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Hope this helps and if you have a specific
question, just post it and I'll do my best to help...Tony
P.S. As you can see from the "disasters", the aftercooler tells it all about
what's going on in the engine room. Exhaust leaks, saltwater dripping on or
near the intake air, impellers that fail, etc... |
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