D1-30 heat exchanger tube removal

[Bobb]

about to take out the tubes and clean them from a D1-30. The cover can be removed either forward or aft, and one Volvo manual describes doing it from the aft end. But fwd is far more convenient and less work.

Anyone done this? And how many seals did you replace? It seems odd that the cover does not seem to show a seal or gasket.

thanks everyone!

[Salty]

I’ve done it on an MD2020 engine which is not the same as your engine, but on mine the elbows at each end were made from rubber, and the tube nest extended out into those rubber elbows where the elbows were connected with a jubilee clip both to the end of the outer part of the heat exchanger, but also had another jubilee clip fitted around the mid length of the elbow. It was that second jubilee clip that created the seal. with that second jubilee tightened in place, sea water could only go through the tubes, while on the other side of that second clip was now an area where the separate engine cooling fresh water mixed with antifreeze could now circulate, but only around the outside of the tubes. You might have a similar setup so it is important if you do, to ensure that your second jubilee clip fits over the landing area near to the ends of the tube nest.
Hopefully it will all make sense when you pull it apart.

[Rampage]

The exploded parts diagram here (https://www.marinepartseurope.com/en/volvo-penta-explodedview-7746500-26-9710.aspx) seems to show that the tube bundle is sealed with a number of “o” rings (part no 7 on the diagram) and also that the forward end of the tube bundle (Part no 5) has a triangular plate which suggests you can only remove it from the front.  The plates front and back replace the rubber caps of the 20x0 series engines.

[Captain Jan]

I pulled off the front of the intercooler on my D1-30 to investigate an overheating issue and check the tubes.  Negligible lost fluid, never changed o rings, all tubes clear. The overheating turned out to be a faulty connection of the alarm wire blade connector to the sensor on the port side of the block.  Pulled it off, cleaned it up, re fitted & no more alarm.  Hope this helps.