Kad 32 heat exchanger

[martinlsmith]

So I've got the heat exchanger off my Volvo Penta KAD32P, what a nightmare, had to take half the engine to bits.
Doesn't look that bad inside. Any suggestions on the best way to clean it.

Problem I have is will run all day at 1200 revs even push it up to 3000 while sitting still
and have run it at 3000 rpm for 20 mins. temp doesn't go above 80 degrees, put it into gear
take it up to 2000rpm and within 1 min temp gauge is off the scale.

Did have a raw water impeller break up recently and was advised that that had probably got
wedged in heat exchanger but no sign of bits of rubber anywhere.

Any ideas please.

 

[A_8]

So I've got the heat exchanger off my Volvo Penta KAD32P, what a nightmare, had to take half the engine to bits.
Doesn't look that bad inside. Any suggestions on the best way to clean it.

Problem I have is will run all day at 1200 revs even push it up to 3000 while sitting still
and have run it at 3000 rpm for 20 mins. temp doesn't go above 80 degrees, put it into gear
take it up to 2000rpm and within 1 min temp gauge is off the scale.

Did have a raw water impeller break up recently and was advised that that had probably got
wedged in heat exchanger but no sign of bits of rubber anywhere.

Any ideas please.

If your cooling water is routed like my KAD43 the water will first pass through the oil cooler before getting to the heat exchanger and its a lot smaller so any blockage in there will affect the overall flow quite a bit. Just did both my oil cooler and heat exchanger. Found a very long bolt and the threads cleaned the pipes up very nicely.
The heat exchanger was perfectly fine after 11 yrs but the oil cooler had maybe 20% blockage, a pic for inspiration,

 

[A_8]

Problem I have is will run all day at 1200 revs even push it up to 3000 while sitting still
and have run it at 3000 rpm for 20 mins. temp doesn't go above 80 degrees, put it into gear
take it up to 2000rpm and within 1 min temp gauge is off the scale.

Any ideas please.

Reading that again, have you checked that you have any flow of water? If it rises within a minute your raw water pump may have broken. Revving to 3000 rpm out of gear is not relevant, the engine is not doing much work and energy/heat is nothing compared to when in gear @ 3000rpm.

 

[oGaryo]

Welcome to the forum Martin, hope you get this sorted. There's an immense amount of knowledge and experience on these forums so rest assured, you're in safe hands

 

[martinlsmith]

Thanks for that, will try and find the oil cooler, where is it on your 42.

 

[A_8]

Thanks for that, will try and find the oil cooler, where is it on your 42.

Its under the heat exchanger, if yours is in the same place you should be able to see it if you have gotten the exchanger off.

 

[aquapower]

I have just removed and cleaned my coolers, as said above the oil cooler is first stop after raw water pump and is most likely to get blocked, I snapped off a bolt in mine so ended up drilling out and fitting a helicoil, if you have already removed the heat exchanger then remove the supercharger and then its easy to get at the oil cooler, I had plenty of debris in my oil cooler, I'm doing all this with the engine in my garage as once its fitted I won't have such good access to everything.

 

[martinlsmith]

Cheers for that, looks like you have the luxury of being able to get round your engine. have to hang upside down to get at mine.
Does the oil cooler come off easier than the heat exchanger and am I going to lose all oil when I take it off. looks very similar to the 32 from what I can see.
will go back to boat tomorrow to see if I can see it. Looking again dipstick is other side of engine and I had to move my compressor to get heat exchanger out.
My expansion tank is other side and I don't have that black tube running across the top is that the air pipe from the compressor?, not quite the same as mine. (nor do I have a red socket set case, may be that's where I am going wrong) Are the two black pipes I can see going to the oil cooler oil pipes or are they the water pipes?

 

[martinlsmith]

Hi Aquapower
missed your post to start with, only just got into this forum business. Guess it makes sense that most debris will collect in oil cooler if that is first visit of raw water.
Got the heat exchanger sitting in the kitchen sink at the moment full of kettle descaler. Sure it can't do any harm while its out.
Had a raw water impeller break up on me fairly recently and was hoping I mind find some of that in heat exchanger but not a sign of it just a bit of lime scale about.

 

[volvopaul]

Hi Aquapower
missed your post to start with, only just got into this forum business. Guess it makes sense that most debris will collect in oil cooler if that is first visit of raw water.
Got the heat exchanger sitting in the kitchen sink at the moment full of kettle descaler. Sure it can't do any harm while its out.
Had a raw water impeller break up on me fairly recently and was hoping I mind find some of that in heat exchanger but not a sign of it just a bit of lime scale about.

On a kad 32 sterndrive model the impeller debris ends up in the strainer basket as its a after the pump, only shaft drive versions suffer impeller blades in the oil cooler.

 

[A_8]

Cheers for that, looks like you have the luxury of being able to get round your engine. have to hang upside down to get at mine.
Does the oil cooler come off easier than the heat exchanger and am I going to lose all oil when I take it off. looks very similar to the 32 from what I can see.
will go back to boat tomorrow to see if I can see it. Looking again dipstick is other side of engine and I had to move my compressor to get heat exchanger out.
My expansion tank is other side and I don't have that black tube running across the top is that the air pipe from the compressor?, not quite the same as mine. (nor do I have a red socket set case, may be that's where I am going wrong) Are the two black pipes I can see going to the oil cooler oil pipes or are they the water pipes?

The black tube is the air pipe from the compressor and the 2 black pipes are oil pipes however given volvopauls input and if you are on outdrives it is more likely you have a broken seawater pump as I mentioned before, there is a plastic type part connection for the pump that can break if it has too much load (its designed to as far as I am told). You can clean the oil cooler from general growth without taking it off by removing one lid and cleaning the piping like you do the heat exchanger.
If you already have taken it apart it makes sense to clean the oil cooler too but I would look at the pump more closely and confirm its actually turning.

 

[aquapower]

On a kad 32 sterndrive model the impeller debris ends up in the strainer basket as its a after the pump, only shaft drive versions suffer impeller blades in the oil cooler.

I agree that impeller parts should be retained in strainer but I had fair bit of silt and parts of broken impeller that had passed through strainer in my oil cooler, I'm going to fit new strainer as its not in great condition.