annoying overheat on KAD32's (lots of data)

[RIN]

annoying overheat on KAD32\'s (lots of data)

Hi all
We're having a dickens of a job trying to sort out the cause of overheating on our port KAD32.
The alarm goes off somewhere between 85 and 90 C. (from the guages on control panel)
So far we have
1) checked impeller
2) swapped alarm sensors port to stbd
3) swapped front impellor plates port to stbd
4) swapped the alarm contol box behind the volvo conrol panel port to stbd
and the alarm still goes off on the port engine (only when doing 25+knots)

So bought an infra red thermometer to check the temperature of various components on both engines when the alarm goes off.
Ably assisted by volunteers we did three runs, stopping when the alarm went off and taking immediate measurements
Run 1-------------------Port-----Stbd
Thermostat Housing-----81.6---105.9 (the temp alarm sensor is here)
Heat Exchng front of----68.9-----69.9
Heat Exchng rear of-----85.9----69.8
Ex. Elbow---------------41.5----51.2
Water Pump Housing----49.0----49.0 (the temp guage sensor is here)
Oil Filter-----------------61.5----51.4

Daft really as it was the port alarm that went off. Noticing the high oil temp on the port engine we changed the port oil filter and after a rest, tried again and this time took it straight up to 30 knots

Run 2--------------------Port----Stbd
Thermostat Housing------83.7----98.9
Heat Exchng front of-----72.4-----71.1
Heat Exchng rear of------63.1-----66.4
Ex. Elbow----------------40.9-----49.6
Water Pump Housing-----53.1-----52.8
Oil Filter-----------------67.3-----65.8

At this point there was coolant coming out of the stbd filler cap
so we swapped coolant caps then went straight off (thankfully you are thinking) for a final run

Run 3--------------------Port----Stbd
Thermostat Housing------99.0---101.0
Heat Exchng front of------66.0----66.8
Heat Exchng rear of-------65.0----66.1
Ex. Elbow-----------------42.4----53.2
Water Pump Housing------54.5----53.6
Oil Filter------------------68.8----66.5

Now can anyone make any sense of this? does the data point to anything on the port engine that is worth checking? My only observation is that the stbd engine should be the one setting off the alarm but the wiring is all on a loom so I don't see how the alarms could be crossed over.

Any suggestions on what we can do next gratefully received.

Richard

 

[alt]

Re: annoying overheat on KAD32\'s (lots of data)

Someone mentioned before about a bad earth going to the temp gauge... maybe try a fresh earth?

 

[KevB]

Re: annoying overheat on KAD32\'s (lots of data)

I had a problem recently with my port KAD43 regularly overheating. Everything seemed OK including the impeller...... Called seastart who within minutes found the probelem. Although both impellers were fairly new (3 months old) the one on the port engine hadn't formed the correct shape in the housing so not creating a tight seal and unable to draw up water properly. Turning the impeller round, effectively putting it in back to front, sorted it.

 

[volvopaul]

Re: annoying overheat on KAD32\'s (lots of data)

Sounds like a faulty alarm sender its at the back of the exhaust manifold if its the same as the one I have recently done head gasket on, if the temp gauge isnt reading nearly 100 c then its not overheating, could be a blockage in the leg though the speed of water pushing against it should help.
Could be the power steering cooler blocke dif its on that engine or and air leak, check all hoses before the pump, last thing is if its making water ie pressure in the header tank the its the head gasket and also if it it replace the injector copper sleeves as they were leaking on my job.

Ah one last thing volvo have had a bad batch of fresh water pumps, as the impeller is plastic it falls off the shaft therefore no flow, bet its that had some on some 42s and 43s.
Thats another reason why it will push water out the header tank, where is the boat?

 

[RIN]

Re: annoying overheat on KAD32\'s (lots of data)

Paul

Boat is at Poole. The power steering comes off the starboard engine so that will not be causing the problem. Also the vent of cooling fluid when at WOT was also from the stbd engine. That might be a problem for sorting out once i have got the alarm problem sorted on the port engine.

Does the KAD32 have an exhaust manifold temp sensor? I tried tracing the one on the thermostat housing back to the control panel but it does not appear to be wired in the same way as the volvo manual I have.

The engines are only 3 years old (330 hours) and we rarely cruse at more than 22 knots so I am hoping the head gaskets are ok

Richard

 

[volvopaul]

Re: annoying overheat on KAD32\'s (lots of data)

The alarm sensor is at the back of the exhaust manifold you can hardly see it due to heat exchanger and all the other bits and they do play up.

 

[gimmesunshine]

Re: annoying overheat on KAD32\'s (lots of data)

not much help but common problem is over filling with coolant with 32's, the header tank is on the small side and best to run near the min rather than max
so let the level settle
doesnt help with overheat though
have heard face plates wear, they should be smooth, have no grooves

 

[Peanuts]

Re: annoying overheat on KAD32\'s (lots of data)

Richard
Didn't know you had a problem (just seen PM) Interesting set of measurements!!
The only item you haven't changed would of been the one I would have and that is the temperature switch as this is the item that sets the alarm off and is set at 97 degrees c.
Although you have the alarm going off what does the relevant temp gauge read, I know you have stated 85-90 but does it reflect port gauge over heating. From your measurements I would be looking at the stbd engine, although on run 3 the port engine is showing 99 deg but this could be from heat soak and would cool down after a short while of running.
I see you have swopped the impellors and the front plates (I wonder how you knew about that one?) but it could be the rear of the pump body that is worn, it might be a swop over of the sea water pumps.
I think I would also check the wiring by ringing out thru from the temp switch to the alarm panel, just to make sure port engine goes to the port alarm panel, it wouldn't be the first time it didn't. With the temperature you have on the stbd engine it should be that engine that has the alarm going off not the port, so remove the cable off of the temp sensor (brown/white cable) and at the alarm panel pin 3 (still brown/white) and check for continuity, at least that would confirm port engine to port alarm panel.
I know you say you are at 25kts but then you stated 30kts, so at what throttle setting are you having this problem, is it at W.O.T. together with a dirty bottom or even the outdrives blocked by some of those giant Davis's barnacles!!
I hope this is of some help together with some of the assistance from the rest of the forumites.
Let us know how you get on.

Steve

 

[Peanuts]

Re: annoying overheat on KAD32\'s (lots of data)

Sorry Richard
Forgot to mention, remember temperature switch controls the alarm panel and is set at 97 degrees. The temperature sensor controls the gauge readings. OK

Steve

 

[Seadee]

Re: annoying overheat on KAD32\'s (lots of data)

Lost the reading from my Nanni 4.390 TDI engine temp gauge about 2 months ago 'cos the spade connector on the top had broken. Duly obtained replacement from AR Peachments in Brundall. Engineer replaces sensor - no problembos. First trip out engine gets to 85 degC and alarm goes off. Bottom twitches, frantic lifting of deck hatch - engine sitting there right as rain. Eventually I disconnected the alarm lead, left the gauge lead connected and motored home. After much tooing and frooing by my engineer (Mark Rix of Marine Revolutions is a top bloke) he diagnoses that the sensor is faulty. I'm now on my 4th sensor as Peachments sent me the wrong one for my engine (!!) The one the sent originally was calibarated to alarm at 83 (so it was working correctly after all but it was totally wrong /forums/images/graemlins/frown.gif). I finally got Nanni in France to confirm the part number, guided ARP in the ways of customer service and now we are away - my tip is don't trust the main dealer to give you the right replacement part - check, check and double check.

 

[trialframe]

Re: annoying overheat on KAD32\'s (lots of data)

I had overheat on older AQD40. Took forever to realise it was air being sucked into impeller pump housing only when engine under quite high load. Replacing appropriate seals in the water pathway cured problem- which didn't happen at low rev ranges.

 

[RIN]

Re: annoying overheat on KAD32\'s (lots of data)

Steve

I tried the continuity from the temp switch to the brown/white terminal on the control panel plug and could not get any. I tried to all others on the plug and found I had continuity to the brown wire and the white /blue wires. (couldn't work out what pin numbers they were though) I can only suppose the wire colourings on the loom are not as listed in the volvo manual - still have not figured why there is continuity to two wires in the plug. More work to do in this area I think.

What really bugs me is the temp on the thermostat housing was in the low 80 (from my thermometer) when the alarm went off (I discount the last run as there probably was a lot of heat in the engine by that time). This indicates there is no overheating problem with the port engine!

I also used the wrong word earlier in my post. It was the temp switches that were swapped over.

The problem occurs at around 25 knots at (for us) fast cruising speed. Going straight to 30 knots caused the overheat much quicker. The guage was definitely between the 175F and 200F marks on the dial - probably nearer 85C than the 97C for the switch to close

still baffled!
Richard

 

[Viscount]

Re: annoying overheat on KAD32\'s (lots of data)

AFAIK the simplest way to be sure that the port and starboard are not crossed is to take the wire that attaches to the port temp switch and connect it to earth (with the engine electrics on); that should trip the relevant warning light and alarm.

 

[alt]

Re: annoying overheat on KAD32\'s (lots of data)

What temp should the gauges be reading at WOT?
And what temp does the alarm go off at? 100celcius?

 

[RIN]

Re: annoying overheat on KAD32\'s (lots of data)

not sure about WOT. Think 80-90c is operating range. As Peanuts says, the temp switch should set the alarm off at 97c

 

[Peanuts]

Re: annoying overheat on KAD32\'s (lots of data)

Beat me to it Richard, the average range is 75 - 90 with as you say the temp switch set at 97 degrees c. Each engine runs different, on my boat the stbd runs a tant cooler mainly because of the hot water tank, but both are within the range. However mid season, put my work mates on the boat for a day out, W.O.T across Poole Bay and I can get an alarm to go off, just drop back 300 RPM and all is OK.