Heat Exchanger 8V71N

[savarese1]

We are going to attempt to remove and clean our heat exchangers as well as replace our anodes. If anyone can share any helpful hints or tips we would greatly appreciate the insight. We do not anticipate this to be extremely difficult but we have never done this before.

Thank you

Joe

[cattledog]

I need to replace my anodes on a pair of 8v71ti's as well.

One annoyance is that I haven't been able to find a good list of all the anodes in the engine so I can buy all the necessary replacements ahead of removing the old ones. Without a good list of all the anodes in the engine, I have visions of pulling the old anodes out then not having all the new anodes needed to put the engine back together.

If its been a while since you have replaced your anodes you will probably have to replace the cap and the anode at the same time for most of them.

Good luck and if you can post a list of the anodes that you used that would be great.

[saltshaker]

We are going to attempt to remove and clean our heat exchangers as well as replace our anodes. If anyone can share any helpful hints or tips we would greatly appreciate the insight. We do not anticipate this to be extremely difficult but we have never done this before.

Thank you

Joe
Not a difficult job from a skill standpoint but it's a bear to handle getting the heat exchanger off the engine and out of the boat. I'd remove the cooling pipes and clean/paint them while you're at it. It's also a good time to service the coolant pump if needed. I've opted to have my mechanic do this as he's much cheaper than the orthopedic surgeon.

[SEVEN]

Have you looked into Barnacal Buster? Look on utube under BB to see how it works. It's a lot easier to do that than removing the heat exchanger and having it boiled out. Cheaper too. Good luck.

[MikeP]

I recommend that if this the first time that you do as planned and pull them/boil them as per the DD recommendations. This will give you the opportunity to inspect then and ensure they really are clean. Cleaning in place will not clean anything OTHER than calcium buildup. IF there are impeller parts, zinc chunks, silicone squeeze-out, etc, cleaning in place will have no effect on those bits.

If you pull/clean them the first time you do it to be sure that they are like new at that point and working as well as they possibly can.

FWIW, some folks do not use zincs in the HEs or the water pump to preclude zinc pieces from clogging the HEs. The water rushing through the system will erode/crumble the zincs.

[Glory]

The heat exchanger isn't heavy, the tank is heavy. Look in the manual, the parts break down works
and remove the exchanger bundle alone. That eliminates the need to remove any trans lines, and the mess from the oil draining and the fresh water plumbing.

You can then clean the bundle with caustic soda, muriatic acid or barnacle buster. Also have a good look in the tank, and clean as needed. As long as the coolant is drain you can flush the fresh water side.

You'll need the gaskets, and o rings, some call the o rings donuts.

JM

[jim rosenthal]

I've opted to have my mechanic do this as he's much cheaper than the orthopedic surgeon.

Yes, well said.

[rsmith]

The big problem with this job is snapping off the bolts that hold the end plates on. If you don't have a drill and easy out handy you might as well have one standing by.

[saltshaker]

Mine have been done as preventative maintenance. I had some pipes that needed a good cleaning and painting plus I wanted to service the FW pump and coolers. I do this once and then keep on top of it with regular cleaning. For me it's worth the piece of mind to tear it down so I'm starting off with a clean fresh system.

[Tim Powell]

Mine have been done as preventative maintenance. I had some pipes that needed a good cleaning and painting plus I wanted to service the FW pump and coolers. I do this once and then keep on top of it with regular cleaning. For me it's worth the piece of mind to tear it down so I'm starting off with a clean fresh system.


When i rebuilt ny 892's last summer i replaced both salt water pumps ( the shaft on one was worn out and sucking air) and took off and cleaned the the heat exchangers and replaced all the blue hoses. The engines ran flawless this summer. They both never saw hotter than 175 which i understand is the the thermostat settings....I like Jack was doing preventative maintenance. It paid off running in 80 degree water sometime they still ran cool..I mainely hung around Hatteras this summer . There is no good mechanics and lack of DD parts makes you plan ahead with piece of mind.....

[MikeP]

The big problem with this job is snapping off the bolts that hold the end plates on. If you don't have a drill and easy out handy you might as well have one standing by.

I have found that easy-outs can easily turn into "very difficult outs." When you snap off the easy out trying to remove the bolt, you now have a piece of hardened steel in the bolt hole instead of the relatively soft metal of the fastener. It's one of those "occurrences" that turns a 30 minute job into an all day (or longer) one! :)

We once had a guy bring in an engine that had 4 - COUNT 'EM, FOUR(!) broken off easy outs in various fittings. You would think that after the first one he might have decided to try something else. ;)

Just be careful with easy outs... ;)

[workingonadream]

ditto what mike said. be careful with easyouts. I wouldn't use them for that reason. I would drill and tap instead if necessary as it will likely be much quicker than drilling an easyout. I would also replace all the bolts with new ones. good luck

[brico]

We are going to attempt to remove and clean our heat exchangers as well as replace our anodes. If anyone can share any helpful hints or tips we would greatly appreciate the insight. We do not anticipate this to be extremely difficult but we have never done this before.

Thank you

Joe

I recommend that you at least remove the heat exchanger core from the tank in order to properly clean it. Here is the post I started last winter when i did the work on mine. http://www.samsmarine.com/forums/showthread.php?25118-Muriatic-acid-Oxalic-acid-Water-mixture-effectiveness
There was so much crap in them that I do not believe simple insitu flushing with muriatic acid would have worked. Now i know they were both properly cleaned and I religiously use the drains on my tanks that previous owner did not even though they were provided so my tanks are dry at all times when engine is not running and that is 95% of the time when the scale from sea water is slowly but surely building up in them and reducing their effectiveness.

[LIBERTY]

Just did the overnight soak with Barnacle Buster on my 871TIs. Very pleased with the results. Opened up the heat exchangher on the raw water pump side to take a look. Very clean. Flushed four AC units as well. Got to get better performance after all the foaming.