Heat Exchanger inspection Volvo Penta D1-30 engine

[Newf]

Finally got around to inspecting the heat exchanger and exhaust riser on my 2014 R21-EC. (Volvo Penta D1-30 engine) Boat is used in salt water only. Inspection completed at 1460 hrs.

At around 1400 hours I started to see some “goop” starting to leak around the face of end cover over the exchange core. After removing the cover it appears that salt water was seeping pass the o-ring in the cover resulting in salt deposits accumulating in the gap between the two o-rings that seal against the heater core. (One in the cover and one in a recess in the exchanger housing) This salt/calcium material was built up in this gap between the two o-rings to a point where it hardened, expanded and warped the end cover plate (made of plastic) which allowed it to seep under the cover and was what I was seeing as leakage around the perimeter.

This salt build-up, trapped between the two o-rings, also corroded the edge of the exchanger casting that forms the recess for the inner o-ring where it seals against the heat core. I will have to attempt a repair with some sort of metal epoxy to allow the o-ring to make a good seal around the core. (Maybe a JB marine weld material or Belzona)

I had not removed the end cover previously so an earlier inspection would have revealed a leakage pass the o-ring and this material build-up at an earlier stage. Definitely a lack of preventive maintenance on my part. Not an excuse but this is my first boat and was not familiar with the heat exchanger and how it functions or the importance of flushing or inspection. For those who are more knowledgeable than me and use their boats in salt water-----How often do you flush the heat exchanger? How often do you remove the end covers to see if there is any blockage or buildup in the tubes? How often do you remove the heater core itself for inspection or service?

For those interested or those with the D1-30 engine I have added a few photos in my album showing the build-up, as trying to describe it here is probably not very clear. Haven’t got good pics that show the corrosion on the edge of the housing. If you have further questions on this feel free to contact me.

After I removed the core I gave it an acid bath as recommended by the Volvo mechanic to remove the accumulation that was starting to build-up on the outside of the tubes. He noted that even minor build-up with affect the cooling efficiency of the tube bundle. The core now looks like new.

The exhaust riser had no heavy build-up or sign of blockage and appears to be only a light layer of exhaust soot.

I’m now waiting for a new cover to arrive and will attempt a metal epoxy repair before reassembly. Thinking that after another 100 hrs I will remove the end cover again to inspect and ensure that there is no seepage past the cover o-ring.

 

[REO6205]

Thanks for posting this. I'll definately add it to my engine file.

 

[Newf]

Just an update to this old post from 2018 for info only to those that have the D1-30 in their R21-EC's. I used Marine Tex to make the repair to the corrosion that I found on the heat exchanger in 2018. Since then I have inspected this area a couple of times and everything looked good until my last inspection a few weeks ago with almost 3500hrs on the engine. The Marine Tex repair was starting to crumble and additional corrosion was visible again on the heat exchanger. I removed the heat exchanger/exhaust manifold to make it easier to work on and removed the old Marine Tex material. Decided to try another repair and this time used JB Marine Weld. After repair and reassembly I had a small glycol leak indicating that it was leaking past the inside O-ring. This was not totally unexpected since the repair was shaped and ground by hand instead of being machined. Pulled the end cap and o-rings off and applied a bit of JB-weld RTV Sealant. I've had the boat out on a couple of 6-7hr fishing trips since this and all looks good. Hopefully it last for a couple thousand hours.

The photo showing the end of the heater core was the as found condition in 2018 after removal of the end cap. I did not see this type of accumulation in subsequent inspections so no leaking past the o-ring in the plastic end cap.. The other photos are of the corrosion found recently after I had the Marine Tex repair cleaned up. Obviously some of this corrosion had occurred prior to my first repair in 2018.

I was wondering if others, with the D1-30, have had any such issue as searches on other forums show that this is not an uncommon issue.

 

[Rode Trip]

It's a common problem with all engines. Normally a 'every 2 years' item to remove the end caps, clean, and replace the o-rings.

 

[Newf]

It's a common problem with all engines. Normally a 'every 2 years' item to remove the end caps, clean, and replace the o-rings.

Thanks for your reply. I have read that it's a known issue with the VP D1-30's but had not read of the same issue with other makes or models. You would think that it's one that should be easy to solve. The o-ring are compressed against the end cap on the tube bundle to keep the glycol in and the raw water out. It's in a very low pressure situation with no movement, so no wear on o-rings to speak of, so seepage past the o-rings should be a non issue if properly compressed against smooth surfaces. The photo is of the end of the tube bundle on mine. (Taken in 2018) Not perfectly clear in the photo but clear enough to see the undulations between each of the tubes on the machined surface. Tough for an o-ring to make a good seal on a surface like that. When I first had the issue a diesel mechanic recommended using Permatex Aviation sealant on all the surfaces and o-rings. This worked with filling in the irregularities until the Marine Tex failed recently but you should not have to apply sealant to a machined surface to fill in "gaps" in my opinion.