KAD44 overheat

[Garychill]

Hi All,

Still trying to sort an overheat on my KAD44….

Question, At idle in the marina what is considered normal ?

(I’ve had different opinions from two engineers, one says 40C is normal and one says 87C is normal)

1) heating up to around 40/45 C and staying there until she’s out and opened up. (Starboard engine) which then holds around 90 C at 2700-3000 RPM

2) climbing up to 87 C at tick-over. This engine then runs at 93 at 2700-3000 RPM (port engine) - this is after a circulation pump failure and some leaks following an overheat (caught fairly quickly)

Appreciate any observations. You can see here the temp at 2800 RPM and then after waiting in the bay for permission to enter the harbour how the starboard engine cools much faster

 

[kashurst]

The temperature in he marina is not helpful. The temp under load and running is. Is you got water tank connected to the port engine? That will keep it warmer for longer. First I would get an infra red thermometer and point it at the thermostat housings and see what temperatures that reveals. Cheap on Amazon etc. Then I would looking at cleaning out the cooling system with rydlyme.

 

[Garychill]

Thanks for the reply - reason i mention the idle temp is that they’ve always held at 40/45 in the marina, even with some revs on. So me it was telling me something had changed with freshwater circuit since the pump failure

Which part of the system would you clean ? Fresh / Salt or both ?

Thanks again !

 

[simonfraser]

rydlyme would go in the internal 'fresh' side, not the external marina side

the heat exchanger may be clogged up for both above circuits, when was it last cleaned out ?

 

[kashurst]

If the engines have had the correct antifreeze in over the years, I would leave the fresh water (antifreeze) circuit alone.
Next step is to rig up a flushing kit and stick some rydlyme through the fresh water side. Your engine temps are a bit high but not terrible, which indicates the coolant heat exchanger is a bit fuzzed up. If that is, then its likely your charge air cooler (turbo heat exchanger) won't be doing the business either. If you search for rydlyme on this forum I vaguely remember a few people have done it with pics. You will get the idea. I did mine with aqua fuerte in Spain which is weak hydrochloric acid - which is what rydlyme is mostly to be honest. KADs don't have any cooling system anodes to worry about either. Some people use brick cleaner but unless you know how strong it is be careful. Better to dilute it and take a bit longer.

The alternative is to strip and clean all the heat exchangers, which given the age of the engines might not be a bad idea either. Have a good look at the oil coolers too. If the end caps are looking all white and corroded it might be time to bite the bullet and do it all properly. Again loads of people on here have done it so have a search. Its not especially difficult - subject to access but there is quite a lot of parts to sort. Access to begin with will probably be tight, once you get the main heat exchanger off the engines look a lot smaller and there will be more room. If you do decide to do all that, take the raw water pumps off too and fit a new OEM volvo seal etc.

 

[Mr Googler]

rydlyme would go in the internal 'fresh' side, not the external marina side

No it wouldn’t

 

[petem]

If the engines have had the correct antifreeze in over the years, I would leave the fresh water (antifreeze) circuit alone.
Next step is to rig up a flushing kit and stick some rydlyme through the fresh water side. Your engine temps are a bit high but not terrible, which indicates the coolant heat exchanger is a bit fuzzed up. If that is, then its likely your charge air cooler (turbo heat exchanger) won't be doing the business either. If you search for rydlyme on this forum I vaguely remember a few people have done it with pics. You will get the idea. I did mine with aqua fuerte in Spain which is weak hydrochloric acid - which is what rydlyme is mostly to be honest. KADs don't have any cooling system anodes to worry about either. Some people use brick cleaner but unless you know how strong it is be careful. Better to dilute it and take a bit longer.

The alternative is to strip and clean all the heat exchangers, which given the age of the engines might not be a bad idea either. Have a good look at the oil coolers too. If the end caps are looking all white and corroded it might be time to bite the bullet and do it all properly. Again loads of people on here have done it so have a search. Its not especially difficult - subject to access but there is quite a lot of parts to sort. Access to begin with will probably be tight, once you get the main heat exchanger off the engines look a lot smaller and there will be more room. If you do decide to do all that, take the raw water pumps off too and fit a new OEM volvo seal etc.

I think you meant to say flush the sea water side above.

 

[kashurst]

I think you meant to say flush the sea water side above.

Well spotted, thanks Pete, yes flush the sea water side

 

[Garychill]

Found this handy YouTube video of the sea water flush - same engine as mine too

 

[nfluester]

Found this handy YouTube video of the sea water flush - same engine as mine too

love that people are finding this video so useful, I have a pair of Volvo D6's now in the new boat so hope to make a new version int the near future