Beta heat exchanger

[30boat]

My Vega had an overheating problem at tickover but was ok underway. The water from the exhaust seemed less than usual. The impellor was ok so I removed the heater tube stack...........big mistake!

The stack was pretty gunged up so that was duly cleaned, the problem was when I put it all back together. I just could not get a seal on the aft end cap. Water was pouring out no matter what I did regarding seal fitting and end cap tightening sequence .I have done this job numerous times before with no trouble.

On closer inspection the rear end of the heat exchange tank was seriously pitted and eaten away. I was never going to get a waterproof seal as there was nothing left to seal to.

The problem was compounded by not only the difficult access to the rear end of the heat exchange tank on a Vega resulting in alternating between hanging upside down leaning into the engine compartment or crouching in there and peering up to the left whilst trying to work mainly with my left hand. In addition to being stuck up the top end of Loch Sunart a long way from workshop facilities and or chandlery.

I contacted Betamarine, after explaining the problem to the tech support guy he asked me the year of manufacture of the
engine. I told him 2006, he immediately stopped trying to tell me how to fit the O ring seal and said I had 2 options. First option buy some epoxy and rebuild the area that had been eaten away or replace the tank with the new improved version. He was keen to stress that as it was a design fault ( not his words ) he could sell me one at a special price. As the required clearance above the tank to clear the studs was to much for a Vega the engine would require removal I opted for the first option.

I eventually succeeded with the epoxy. The reason for this monologue is to warn you if your engine is of a similar vintage do not remove the heat exchange stack. Remove the end caps, a large Phillips screwdriver in the bolt hole and worked side to side will break the encrusted seal, and clear the tubes insitu with a suitable sized screwdriver or metal rod. New O rings and feel allround the caps to ensure the seal is located as you tighten.

The Beta heat exchanger is no doubt a bad design.mine is older than yours(2003)but until now I've been lucky enough for it to seal everytime I clean the tube stack.The thing is made of aluminium if I'm not mistaken and that's a really poor choice of material.

 

[spottydog]

It was astounding the amount of corrosion in a short space of time. Possibly due to not replacing the pencil anode often enough.

 

[BabaYaga]

It was astounding the amount of corrosion in a short space of time. Possibly due to not replacing the pencil anode often enough.

Possibly, but perhaps also due to the endcap being installed in such a way that it was in contact with the tank? Should be isolated by the o-ring I believe. Was the water pouring out raw or fresh?
Curious to know how such a thing might occur, as I my Beta is also from 2006. I take the stack out for cleaning every other year, no sign of corrosion so far...

 

[RogerLS]

Um - in fact there is something holding the end cap in place when the bolts are removed and that is the O ring. Particularly if you dont replace them every season they can stick or go hard and stop sealing. Did you winkle out the old O ring before trying to push the tube stack out?
If you have the Bet with the crossover exhaust manifold and the 60 amp alternator the stack will not go out of the back and need the alternator belt removed and alternator swung right out of the way for it to come out of the front.
Just for the sake of completenes; if you have the oil pressure measuring instrument panel as well then you need a longer non standard alternator belt.