Engine help wanted please - KAD32 Alarm

If the pump faceplate is scored with grooves, get it machined smooth by a local machine shop to you, or you may be able to just reverse the pump plate so you are using the other side if the screw holes are concentric (you will probably have to scrape the volvo green paint off first though).
 
If the pump faceplate is scored with grooves, get it machined smooth by a local machine shop to you, or you may be able to just reverse the pump plate so you are using the other side if the screw holes are concentric (you will probably have to scrape the volvo green paint off first though).
.

When a new Genuine Jabsco faceplate retails at about £15 it's a throw away part, not worth machining.
 
I'm pretty sure that the problem is the circulation pump
It's not uncommon that the shaft breaks on these pumps.
It's not possible to see and the belt spins the wheel on the pump as it should
The pump must be removed to see the problem
 
I also checked the air filter (metal can and re-attached it). Again, to no avail.

Metal can with perforations sounds like crank case breather filter.
The air filter is in the big black plastic box.
but doubt that is irrelevant.

Sudden onset of the overheat fault sounds more like blockage on intake.
I did hear of an overheat fault , which was cured by a new pump ,but in that case overheat only occurred when trying to go fast .
 
Hi engine experts

I went to the boat today armed with my new knowledge and your suggestions. I started the engines, felt for temperature changes on the water pump cover plate...no change. Idled the engines for 25 minutes. No issue. Took the boat out for 30 minutes at idle and compressor/turbo usage - no issue.

It seems to have fixed itself be it plastic or a blockage. The temperature rose to around 80c on both engines when doing fast runs, back at 4 knots if dropped to 40c.

Good news all round.

I wanted to thank everyone for giving their advice and suggestions so quickly. This forum is fantastic for advice and queries. Thank you.
 
Hi Jimmertek, hoping you are still around on here as the original post was 4 yrs ago. I have exactly the same issue on one of my KAD32's you had. Mine happened once about a month ago, then seemed ok for a couple of weekend trips. Now it's just happened again. Did your overheat issue come back and did you ever find the cause? My engineer is thinking it might be sticking thermostats related?
 
Hi,
I also have this issue with the occasional over heat at low speed which seems to magically resolve itself every time the mechanic comes to check it out. Exactly the same with the oil pressure dropping as well.

my mechanic is due to be removing the heat exchanger soon because we have exhausted other options.

thermostats have been replaced, acid run through to break down any blockages.
now she seems to hit 200F when doing 20-25knts but drops as the speed drops.

the mystery continues for now...
 

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Hi,
I also have this issue with the occasional over heat at low speed which seems to magically resolve itself every time the mechanic comes to check it out. Exactly the same with the oil pressure dropping as well.

my mechanic is due to be removing the heat exchanger soon because we have exhausted other options.

thermostats have been replaced, acid run through to break down any blockages.
now she seems to hit 200F when doing 20-25knts but drops as the speed drops.

the mystery continues for now...
You have an electrical issue not an overheat check the earth cables Back of dash loom , stud on alternator that’s where the loom picks up it’s earth , engine block stud .
 
You have an electrical issue not an overheat check the earth cables Back of dash loom , stud on alternator that’s where the loom picks up it’s earth , engine block stud .

Thank you! Will certainly get the electrics tested.
however, the strainer cap physically snapped off under load recently and I’m assuming this can only be from massive back pressure or blockage. Although we are baffled that it has done that but can still run fine most of the time.
 
checked exhaust elbow for blockages that wouldn't have been picked up from the heat exchanger flush?
 
checked exhaust elbow for blockages that wouldn't have been picked up from the heat exchanger flush?

flushed exhaust elbow and cleared a large amount of soot out in the process.
I think when she comes out of the water for this winters service the whole fresh water system needs overhauling. There’s got to be something stuck in there somewhere causing reduced flow.
 
Thank you! Will certainly get the electrics tested.
however, the strainer cap physically snapped off under load recently and I’m assuming this can only be from massive back pressure or blockage. Although we are baffled that it has done that but can still run fine most of the time.
An impeller cannot create massive back pressure just flow restriction if it’s path is blocked , back flush from the exhaust elbow as you might have parts of impeller stuck in the oil cooler
 
An impeller cannot create massive back pressure just flow restriction if it’s path is blocked , back flush from the exhaust elbow as you might have parts of impeller stuck in the oil cooler

Have instructed our engineer to look at doing this next week. Thanks for the advice. He suggested that the cap could’ve snapped as it was old and brittle but Everyone I speak to says they’ve not heard of that happening and that sounds like it’s due to too much pressure through flow restriction or airlock.
I have seen lots of posts about kad32 overheats and never seen anything about the strainer cap snapping off.
 
The beauty of having 2 identical engines is that one can be compared with the other. I find using a cheap hand held infrared digital meter{like is used for covid temp checks] comparing areas on both engines from cold may indicate a problem .Also swopping the send wire on the back of the gauges might eliminate a faulty gauge.
 
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