KAD 32 heat exchanger

STEVEDUNSTABLE

STEVEDUNSTABLE

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Hi All.....finally got Thanks Mum flat-out on a bit of mirror calm Southampton water over the extended weekend...now I will say that this a "sort of creeping problem" in as much as its been a niggle but I must "deal" with it in the closed season...engine temp is fine up to about 24/5 knots then the gauge starts to climb abit to far and rapid (well over the 100degs, but the alarm doesn't come on, yes it does work when the filter got full of weed at low springs in lymington) for my liking..temp drops pronto as the load is reduced almost instantaneously ...my suspicion is the heat exchanger might have some gunge in it as the intake is clean the impellor was new at Easter and there has been no "bits of rubber in the filter (or weed etc)..so that just leaves the exchanger itself..SO.......1, is it a DIY joby?..2, what are the pitfalls?... 3, is it a "saw the boat in half" to get it out/off ?..... for the record (as most of you know) T.M. lives on the trailer, is ALLWAYS freshwater flushed even after the briefest of dunking's and the exchanger has never been removed from new (12yrs).....any thoughts, criticisms, advise, abuse all GREATFULLY received from the knowledgeable forum posse...THANKS IN ADVANCE......Steve..
 
With time the seawater side of the cooling system scales up with a lime scale, if you squeeze one of the black seawater hoses on the engine you will feel it crunching off on the inside of the hose.

The heat exchanger is the worst of the lot with its long fine tubes and you often find some of these completely blocked and the water flow substantially reduced.

You really want to remove the lime scale from the whole engine including the bits you cant get to.

We recently treated both my engines with Rydlyme and American product that dissolves limescale.

Take out the seawater impeller and rig up a small pump that draws the diluted Rydlyme from a bucket or plastic box, runs it through the entire seawater side of the engine ( if two rig them up in series together) and returns the Rydlyme solution to the box for further use.

To test if its chemically spent drop a small sea shell into the solution if it dissolves its still active as it fizzes away like an alka seltzer, if its chemically spent nothing happens and you need a fresh solution.

We ran it through my two VP 63's in series we used to solutions about an hour each and its amazing what it clears out.

Its a mild solution you can put your hands in it but at first it froths away like hell make sure your bucket or plastic box is large or the foam will run everywhere.

When you look at a copper alloy cooler stack that has been cleaned in brick cleaner it goes pink meaning the alloy has been attacked and probably the zinc reduced? With Rydlyme the green cooler stack returns to a yellow colour like a new one and all the scale is removed.

We use it to clean cooler stacks in a plastic windowsill flower trough but running through the engine works best.

I was well pleased with what it did to my engines.

See http://www.rydlymemarine.com/ or co.uk
 
Using a Maplins infra red thermometer I would check your diagnosis , then dicide what to do ,ie rydlime ?
Age effects the resistance of the wires -+ things in the black boxes and as a result gauges can give false " highs"
This expians why your alarms set to trigger @ -94oC have been silent .
Hold it on the cooler or thermostat housing and repeat 24kt and WOT excercise.
 
Could the same symptoms be due to a thermostat that is, perhaps, not opening fully?
I think there are two thermostats on the kad32. I am guessing thermostats are a much easier thing to investigate compared to the heat exchanger.
On the other hand , with your boat on the trailer and the aid of a couple of buckets you can presumably flush with the rydlyme stuff without taking anything apart ?
 
Steve - with the boat kept on a trailer you are ideally placed to Rydline your engine yourself. We have had ours done, temps now lower under normal load circa 85 deg (from memory) and hardly climb at WOT. An amazing amoun of "stuff" came out!

The problem is that most boat yards do not let you run up your engines when lifted out & blocked up. As you are on a trailer, i presume at your home, provided the boat and trailer are secure you will not have his restriction, so you could do as follows which avoids having to rig up pumps and gets everything warm which increases the effectiveness.

Get a big plastic 45 gal drum / rainwater butt and cut it down to fit the out drive leg into it so water pick ups will be well covered. Then partly fill the drum to a point above the water intakes on the outdrive leg with Rydline / fresh water mix to the prescribed ratios. Run engines using this mix until engine / Rydline & water mix is warm. Leave to stew for a while. Clear raw water filter (it should be full of crud) Flush with fresh water on muffs. Clear raw water strainer again (it should be full of crud again!). Flush with fresh water on hose muffs again. Job done!
 
Portofino said:
Using a Maplins infra red thermometer I would check your diagnosis , then dicide what to do ,ie rydlime ?
Age effects the resistance of the wires -+ things in the black boxes and as a result gauges can give false " highs"
This expians why your alarms set to trigger @ -94oC have been silent .
Hold it on the cooler or thermostat housing and repeat 24kt and WOT excercise.
Click to expand...

+1 on this

One of my engines does this off and on, infra red gauge showed there was no actual issue, fiddling with wires and gauge cures the problem for a while but I can never pin point exactly what bit it is though takingthe gauge out and home to dry out thoroughly at home cured it the longest!
 
Using a 45 gallon drum your going to need a lot of rydelime and its around £36.00 for 5 litres I use it 50/50 mix when cleaning coolers. You could connect a hose to the leg inlet hose from a bucket then divert the exhaust outlet water back to the bucket to keep the cycle going, you may just need 10 litres then. Or take the coolers off, intercooler is easy just take the lid off and lift it out, dunk it in a 20 litre drum with the side cut off, then take the heat exchanger and oil cooler off which is a nice winter project. Then put us a vid on u tube.
 
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