Calorifier / Water / Engine Coolant Problem

[Byzance]

Hi,

I've just taken ownership of a 2006 Bavaria37. Back in the water and on my range of checks I found that the engine coolant is overflowing when I pressurise the water system. Its a volvo 2030 saildrive with a QL (20lt) running off the engine cooling. I'm guessing that there's possibly some frost damage in the calorifier so that pressurising the water system basically leaks into the coolant circuit and up out of the cooling expansion tank comes the coolant.

Does this sound plausible - has anyone come across anything similar? Any other thoughts? The previous owner knew nothing of this so its parhaps happened over the fine Scottish winter!

I can't find anything about repairing calorifiers so I'm guessing its a new one if this is the reason.

Any thoughts welcome.

 

[itspaul]

From what you are saying the calorifier seems the obvious choice if you short cicuit the flow and return off the engine by removing the pipes off the calorifier and joining them together then pressure up the water system any leakage from the calorifier wil confirm your diagnosis i think a new one is the only way

 

[Bobobolinsky]

Dip a finger in the coolant tank to see if it tastes sweet or salty, Could be umpteen things, so start simple. Are you getting any overheat warnings? Is there much "froth" in the header. Check heat exchanger ends, remove them and check tubes clear and that there is no passing between raw and fresh circuits, replace jubilee clips on refitting if rubber ends.
It is not really likely that the calorifier is ruptured, you can check by draining the potable circuit. If the header tank keeps overflowing, it is not the calorifier. Replace cap on header tank. Recheck. If it still overflowing, check raw and fresh water pumps. Finally chances are if it is still giving problems that the head or gasket has failed.

 

[Deleted member 36384]

I assume that the engine isn't running at the time. If the engine is running and there was a warped or cracked cylinder head you would normally just loose all the coolant water through the exhaust, the opposite from what you are experiencing.

The accumulator bladder on the water system would of course expand if there was a leak anywhere in the system forcing water out of the leak.

To test just disconnect the engine coolant water from the calorifier and pressure up again and see if the fresh water exists the hose. On my own boat this is quite easy to do.

 

[Byzance]

Thanks all for the quick replies.

I haven't started the engine yet as I don't want to risk sending coolant into the water system.

I have disconnected the engine pipes so should be able to test the calorifier easily. I hadn't thought of re-pressurising the water system to check for water coming out of the calorifier !:-0 Seems obvious to me now! Thanks

 

[Bobobolinsky]

Just to add, a blown head hasket can pressurise the coolant circuit and steam will blow all the liquid in the block up into the header tank. As has been said if the engine has not been started then it is the primary coil. Just check. If an engine has been laid up for a while, I would do all of the checks, I mentioned, It's going to take half a day, but it is a worthwhile check on the health of the engine. On these small engines, also check the injection bend on the exhaust to ensure that it is clear.

 

[david_bagshaw]

From what you are saying the calorifier seems the obvious choice if you short cicuit the flow and return off the engine by removing the pipes off the calorifier and joining them together then pressure up the water system any leakage from the calorifier wil confirm your diagnosis i think a new one is the only way

+1

Also check strength of engine antifreeze, as dilution of it will lead to corrosion etc.

Equally I would carefully bar over the engine before first start in case there is any other damage. does sound as if calorifier has a split in it though, hopefully there will be no other 2ndry damage


Hopefully it will only be because the domestic side froze and damaged the engine side.

 

[Byzance]

I noticed that my answer to the problem never made it onto the forum....so for completeness in case someone else has a similar problem.

The problem was caused by a damaged calorifier as originally suspected. The coolant overflowed when the pressurised domestic water was switched on. It was a relatively simple job to replace the calorifier with another unit although I had to cut back a small portion of the berth woodwork to allow access to remove/replace. I'm guessing the original was fitted before the berth was installed - thanks Bavaria. It cost around 100 for the new calorifier. Better than some of the more scary potential sources of damage!

Thanks to all for suggestions.

 

[PCUK]

Nice to check this feedback, even after seven years.