How to Repair a Heat Exchanger /Insulate an Exhaust Riser:Yanmar Engine-Patrick Childress Sailing 44


what to make a video about today the
only project of all the projects on this boat that are near completion is the
Yanmar heat exchanger rebuild so let’s go take a look at the heat exchanger hello we are Patrick and Rebecca
Childress on the valiant 40 brick house We are hauled out in Richards Bay
South Africa doing a tremendous amount of work on this boat we are preparing to
cross the Atlantic to Uruguay and then (Maybe) head down to Tierra del Fuego but right
now let’s go into the engine room and deal with the leaky Yanmar heat
exchanger. a leak developed at the forward end cap of the Yanmar heat
exchanger at the bottom edge we were out in the middle of the Pacific at that
time with few resources other than what we had on the boat I was able to take
the end cap off clean up the area of deteriorated aluminum and patch it up
with Marine Tex which is a very high temperature what I think of as a super
epoxy then using high temperature silicone as a gasket put it all back
together and it held for the longest time but eventually did started leaking
again so I repeated the repair and eventually now that we’re in Richards
Bay South Africa I felt this with this time to take it off and have the repair
done properly at a radiator shop to get the heat
exchanger off I first had to get the exhaust riser off of the heat exchanger at the
rear end of the engine and that wasn’t easy
I had unwrapped some of the asbestos insulation on the riser to get to the
bolts the only way to get to those four bolts as it turned out was to take all
the asbestos off of the elbow area and when I did that I did wear a tivek
suit some gloves respirator and I had a little spray bottle of water so I could
spray the asbestos before I unwrapped it it was very dry so it would be a lot of
dusting particulate floating around in the air if I didn’t wet it down but all
of this turned out for the better and what a terrible surprise on this engine
that has about 4600 hours on it this elbow the riser it was in terrible shape
it was a disaster that was going to happen somewhere down the line so
fortunately we’re taking care of everything now and not only will we get
the heat exchanger rebuilt but a whole new riser now at the very top of the
elbow you can see the gray marine tex that I use to stop a leak and of course
that’s just a patch certainly not a repair so we were going to be doing some
work on this riser anyway but it’s amazing how well that marine tex
worked in this incredibly high temperature area to plug up some very
small leaks so we have to just disconnect the riser from the exhaust
hose and we’ll get that whole thing out of the way and then continue working on
removing the heat exchanger so by using specific petcocks I have drained all the
salt water and coolant out of the heat exchanger so now we are ready to take
the hoses there’s two hoses on the aft and two hoses off the front section of
the heat exchanger and then release the arm of the alternator adjuster inspect
this hose clamp I’m gonna put all new hose clamps on here no matter what these
look like I don’t want to take any chances
I’ve had these things break on me before this looks fine but it’s gonna get
replaced anyway hunter I’ll throw that one away
that takes a 13 millimeter wrench I’ll go ahead and disconnect that completely
here and so we can fold it right on down out of the way I keep this 13 millimeter
wrench hanging up here out of the way in its sole purpose is to adjust this one
bolt for the alternator okay now we have lots of clearance the
seawater pipe coming in and going to the raw water pump travels underneath the
heat exchanger and is supported there by one bolt so that has to come off before
the heat exchanger can come off of its mount so I’ll continue pulling all these
loose bolts out I was very surprised you look at these bolts there’s no rust on
them easy to undo nothing broke then there it’s one nut on a stud up here and
there is one nut here I’ll go ahead and take off now I’m just worried about
dropping this on my feet I don’t know how heavy this thing is gonna be oh
that’s not that at all I thought it’d be a lot heavier than this that’s nothing
easy okay every once in a while we have a nice surprise so now that we have
everything out of the boat we can take a closer look at this nasty old riser and
get a little closer look at the patch job on the front end of the heat
exchanger so before anything else I wanted to
scrub it down with laundry detergent you get all the grease oil off of it any
residue and flush out the insides with fresh water so that we don’t have any
salt water or antifreeze dripping in the car or on anybody when we hand it over
to the guys that are going to be fixing it so as we dropped off the heat
exchanger I had to go back to the shop and ask these guys how in the world you
get these cores out of the aluminum housing I’ve tried to get this core out
of this housing before and it would not budge so it turns out they soak it in
water for several days and if they have to then add muriatic acid. Now what kind
of acid did you say? Pool acid or you can use a very slight hycloric acid…muriatic acid – pool acid how about like vinegar would that do it as well? Or is that not strong enough. No that’s not strong enough. No no. Hydraulic acid or pool acid…the amount is very light.. normally to 5 liters its like a half a cup, not even a half a cup…its very strong…Soon as see the the small powders, then you know it’s activated so
then you go to rinse it you try and free it or maybe you have to try it again because you
could see as it was cleaning it, around the tube seat, it was opening. you
had to get it all out before you started to bang it. And a couple weeks later we
went back to pick up the rebuilt heat exchanger it was looking really good it
costs us around 250 u.s. dollars and what a big savings that was over the
cost of thousands of dollars for a new one. The thermostat cover was getting
pretty grody I tried wire brushing it and also
sandpaper but that wasn’t good enough so I took it outside and put it to a wire
wheel and that cleaned it up nicely but just to be on the safe side we are
ordering a new one and also a new thermostat. Its just time to put in new parts
and be on the safe side for a long time to come
okay just took the wire brush and this vacuum and cleaned out these exhaust
ports as best as I could and made sure that I didn’t brush things inward even
though I had vacuumed there and try to sweep the contaminants the carbon
buildup outwards towards the vacuum and I’ve also cleaned very well around each
exhaust port and we’re ready for reassembly. So we put on a new gasket and
then hang the heat exchanger and then I’m just sort of putting these bolts in
and I’m not really torquing them down so I can actually work from the right to
the left the best way though when I come back to torque I’ll start from the
center bolts and then work to the right and then come back to the center and
work to the left. this is just a little bit of high-temperature anti-seize it
doesn’t take much It does not matter is that much but you know we
had talked about having this at an angle to go that way to help you water
dispersion go that way rather than that be hard to change? No… so while everything is
nice and clean might as well do some spray painting with some
high-temperature spray paint I got at the automotive store. I’d like to try to
have these hose clamps come off the top so if there is a leak dripping down it
won’t be dripping onto the screw and causing that to rust. it’s the most
vulnerable part especially if the hose clamp is a good 304 or 316 stainless and
the screw might be a substandard stainless or maybe not even stainless at
all hmm okay I’m finally getting these
tightened up and there is one bolt that was actually it’s a screw since there
isn’t a nut on the other side so there is one screw that was just longer than
the others and it goes way in the backside I had forgotten about that but
luck would have it they all went back in to the same holes that they were
supposed to so torquing this I don’t know what the
torque is I would imagine probably about twelve foot pounds but I’m not going to
tighten too much just good and snug as the Germans would say I’ll spray a little
I’ll clean this up with some acetone even though I just sanded it and it
should be, and washed it, so it should be pretty clean I’ll clean it up with a
little acetone and then put some spray paint on there that’s common steel this
plate this mounting plate I didn’t want the stainless steel right up against the
aluminum housing it has to be common steel even zooming way in it’s a little hard
to see the bolt that comes from the aft cabin into the engine room
and that’s a newly added support for the water hose the rest of the riser has its
own support which is just to the right and outside of the picture so everything
is much better supported now than it ever has been in the past taking the
forward cap off of the heat exchanger would void the warranty it had already
been pressure tested but I wanted to inspect the copper core edges and they
were a bit deteriorated as I expected so I would feel much better using high
temperature silicone along with the new o-ring to seal this end of the cap now
once I had everything back together I went and took the cap off of the aft end
of the heat exchanger and much to my surprise there was no gasket there has
to be a gasket to separate the upper and lower sections of straws the water goes
in through the bottom section and then comes out through the top section and
goes up to the riser without the gasket in there all the water the cooling water
floods into this end of the heat exchanger and really doesn’t know where
to go it won’t have the cooling efficiency that it was designed to have
so all I have to do is make a gasket or preferably order one to go in here I’d
rather get one that’s specified for the thickness and everything else I know
it’s going to fit right the first time with no messing around and then I can
always use that one as a guide to make additional gaskets it’s not that big of
a deal I mean the guys working on this did a great job rebuilding it it’s one
of those little oversights but it’s a darn good thing that I did pull these
caps. I’m going to give TOAD Marine a quick plug here we are way up on the
north east coast of South Africa in Richards Bay we could order parts way
down on the southwest tip out of Cape Town but they generally first have to get the
parts from the US. well we can just order the parts from the US just as easier
itself and it actually saves us a lot of money we’ve been using Toad Marine for
our Yanmar parts for a long time they do a great job they ship internationally
they help give a lot of schematics it’s just
they alleviate a lot of headaches you need any parts check out Toad Marine
finally we can wrap this thing up I still have the old asbestos insulation
but most of that is pretty ratty it’ll have to be thrown away and I went out
and bought this new fiberglass insulation it is actually glass fibers
you don’t want to touch it you think asbestos is bad I don’t see how this
stuff is much better if you touch it you get these fibers in your hands and it
itches terribly much worse than grounding fiberglass on the hull of the
boat so I’m wearing double rubber gloves a disposable suit respirator and
tight-fitting goggles so if any of these fibers are floating around in the air I
don’t want to breathe them or get them in my eyes or anything else so I start
on the bottom and wrap it around I use a plastic wire tie to temporarily secure
things and then wrap tightly as I go up with a 50% coverage
sometimes I double up on the wraps and work my way all the way up to the top
and then back around whatever is leftover we work in wrap around in the
down ways downwards direction and then secure it temporarily until I can get
some stainless steel wire ties on they only had one size not long enough to
really fit so I used double I put two of them together so we have those at the
beginning and at the end of the wrap and then I used trolling wire soft it’s a
same thing as like leader wire but it’s very soft and very pliable so it’s very
easy to twist around something like this and secure it rather than just cutting
it off with the wire cutters after twisting it and locking it together I’ll
bend it back and forth back and forth until it finally breaks that way you
don’t have the meat hooks on the end you can rub your hand over it and you don’t
get snagged and same way with the stainless steel wire ties so we have
some good new insulation on the new riser and all we need now is the gasket
for the end cap and we’ll be good to go For a
water test I’ll get the water hose up here even though we’re on the hard and
run the engine and make sure we don’t have any leaks before we ever launch.
I hope this video was worthwhile for you if it was, please give it a thumbs up and
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