My D1-30B is from 2007, has around 2000 hours on it and I’ve never removed the matrix. I give it a work through with a pipe cleaner every couple of years but have never experienced any blockage. I rely on the temperature gauge, which sits rock steady at 90°C, to alert me to any heating issues, but there has never been an issue with the heat exchanger.
Thanks. Do you remove the matrix to do that or do you just use the pipe cleaners from the front with matrix in-situ?
I take both end caps off and you can see right through. I’ve never taken the matrix out, don’t really see the need. I’m usually checking the exhaust elbow at the same time. Any broken off vanes from the raw water pump will be at the front of the heat exchanger behind the end cap.
Have you found a source of Rydlyme in the UK? It appears to have disappeared from the UK market
I bought some from R K Marine a couple of months ago but having just checked their website it doesn’t appear to be currently available….
I have a 2014 D1-30F with just over 3700hrs on it. I have removed the matrix twice in that time. On the first removal there was a bit of crap on the outside of the tubes that would not have been visible without removal. I believe that this was a result of a bit of sea water seeping past the o-rings on the discharge side as there was corrosion in the aluminum casting in that location. Yours may be fine but if I went through the trouble of pulling the end caps off I would pop the core out. Just my thoughts.
Just updating my post with a couple of photos that I found that shows condition of the tube bundle and discharge end of heat exchanger. After cleaning it up there was a fair bit of corrosion on the aluminum casting but fortunately I was able to repair it. This was from the first time I removed it. The second time it was fine. NOTE: When I repaired and reinstalled the matrix on the first occasion, a Volvo Mechanic recommended that I coat the two o-ring with aviation sealant to help address seepage past them. I've had no issues since. Apparently it's not uncommon for seepage past the o-rings which in some cases result in severe corrosion.
Why?
The most well known aviation sealant is Hylomar.
This one.
Rydlyme Marine Descaler. I had some delivered July 2025.
