Maybe this post should be under winter projects.. I decided to remove my heat exchangers and after coolers on my 2001 Volvo TAMD 74's for routine maintenance. My engines are babies with only 400 hours on them but time in the marine environment takes it's toll.. Read all about it on Boatdiesel.com if you have diesels I highly recommend you join (no affiliation).
The heat exchanger comes off first, followed by the after cooler which is part of the intake manifold. The first engine took me 4 hours, the second about 2. After you take the units off (about 50 pounds each), they have to be taken apart. The cooling bundles slide out of the housings. Both the heat exchanger and after cooler are quite similar in design.
There's two problems that you look for when you do this job. One, are the orings that seal the bronze cooling bundles in the outer aluminum cases (the part you see) doing their job and keeping sea water out?
Two, is the sea water side of the cooling bundle in good shape and clear of calcification and debris from old
zincs etc.
In my case all four units were in excellent shape, with regard to 0 salt water intrusion. The saltwater side of
the bundles were surprisingly cruded up with a combination of zinc and calcium, about 25% blocked I would say. So I feel good about my decision to take on this project. I rodded out the passages with an aluminum rod and soaked them briefly in a mild acid bath. As a final step I will than to a radiator shop and have them boiled out.
The parts to put this all back together then right way, with new hoses etc. Is going to run north of $2000, still, a lot cheaper than over heating an engine or having one suck salt water. I also took the valve covers off so I can do a valve adjustment and include them with all the other parts to be powder coated white.
Given the excellent condition of the heat exchanger I will probably only do this service once ever 5 or 6 years going forward..
I'll take some pictures of the process and post them shortly.
The heat exchanger comes off first, followed by the after cooler which is part of the intake manifold. The first engine took me 4 hours, the second about 2. After you take the units off (about 50 pounds each), they have to be taken apart. The cooling bundles slide out of the housings. Both the heat exchanger and after cooler are quite similar in design.
There's two problems that you look for when you do this job. One, are the orings that seal the bronze cooling bundles in the outer aluminum cases (the part you see) doing their job and keeping sea water out?
Two, is the sea water side of the cooling bundle in good shape and clear of calcification and debris from old
zincs etc.
In my case all four units were in excellent shape, with regard to 0 salt water intrusion. The saltwater side of
the bundles were surprisingly cruded up with a combination of zinc and calcium, about 25% blocked I would say. So I feel good about my decision to take on this project. I rodded out the passages with an aluminum rod and soaked them briefly in a mild acid bath. As a final step I will than to a radiator shop and have them boiled out.
The parts to put this all back together then right way, with new hoses etc. Is going to run north of $2000, still, a lot cheaper than over heating an engine or having one suck salt water. I also took the valve covers off so I can do a valve adjustment and include them with all the other parts to be powder coated white.
Given the excellent condition of the heat exchanger I will probably only do this service once ever 5 or 6 years going forward..
I'll take some pictures of the process and post them shortly.
