Heat exchanger core

[Leander Landrum]

Hi guys, I bought a 20 year old boat and the receipts from previous owner showed the last time the heat exchangers and aftercoolers were serviced was 2016. So I pulled them to have them serviced at a local radiator shop. When I pulled them the port engine had clear/teal coolant. The starboard engine had teal, but it was not clear at all. From what I’ve researched this is a sign of saltwater intrusion. The radiator shop called today and said the internals are toast and said the local diesel shop could get replacements. (he said both of them were bad) Is this something that’s worth the effort or should I replace the heat exchangers? Cummins 6BTA 370 year 2000 – they have the older heat exchanger with both outlets going down.

Topic

[Rob Schepis]

I agree with Tony. Do some “body work” or “spackling” on the flat machined ends with JB Weld or grey Marine Tex

[Tony Athens]

Flat surface is marginal to worse

Inside does not matter as much.

If it was me and I was on a budget ( we all are), bead blast the flat surface, fill with JD WELD, block sand flat and let’s see what yo end up with.

Tony

[Leander Landrum]

This is same housing again. It’s the only surface with bad pitting. The rest have none or minimal.

[Leander Landrum]

Rob Schepis wrote:

Leander Landrum wrote:

I still plan to put them back together per the instructional videos you guys have put up.

Post good pictures of your housings – especially the flat machined top and bottom surfaces where the caps mount.

Is this too far gone? Replace or reassemble and and test it?

[Rob Schepis]

Heat Exchanger PSI Test

Leander Landrum wrote:

Roger that. Radiator shop called and both exchangers tested fine.

I would pressure test that heat exchanger from the cloudy coolant engine myself when it comes back from the radiator shop. I am only a true believer with zero doubt when it’s with my own eyes…….

[Leander Landrum]

Tony Athens wrote:

3 – “even” 10 year old low hour coolant is not your issue if all was was good when installed..Something has changed if the coolant went bad. Again, the aftercoolers have nothing to do with the coolant.

Tony

Roger that. Radiator shop called and both exchangers tested fine. I will put her back together, monitor, and get the coolant tested if I see discoloration again.

[Tony Athens]

3 – “even” 10 year old low hour coolant is not your issue if all was was good when installed..Something has changed if the coolant went bad. Again, the aftercoolers have nothing to do with the coolant.

Tony

[Leander Landrum]

Was it black-ish in color? Did you take a pic of it in a glass jar? How old was the coolant?

I just bought her in February, talked to the prior owner and he thinks it hasn’t been changed since 2016, when he had the exchangers and aftercoolers serviced.

[Rob Schepis]

Coolant

Leander Landrum wrote:

I just find it worrisome that one engine had clear teal coolant and the other had coolant that you can’t see 1/2 an inch deep through it. If not saltwater, what could cause that?

Was it black-ish in color? Did you take a pic of it in a glass jar? How old was the coolant?

[Rob Schepis]

Aftercoolers

Leander Landrum wrote:

I still plan to put them back together per the instructional videos you guys have put up.

Post good pictures of your housings – especially the flat machined top and bottom surfaces where the caps mount.

[Leander Landrum]

Tony Athens wrote:

I’m confused– What do the aftercooler cores have to do with the coolant?

As to your coolant looking ODD, not sure if that is what salt water does.. I personally have never seen that from salt water intrusion..

Did the shop pressure test the Heat-Exchangers?

Who is putting your aftercoolers back together? Plenty of radiator shops have no clue on these unique designs although they always say they do.

Tony

The aftercoolers have nothing to do with it, both problems are just surfacing (I bought the boat in February and decided to take those parts off and get them serviced as they were last serviced in 2016).

The shop pressure tested one heat exchanger, they haven’t gotten to the other one yet. I just find it worrisome that one engine had clear teal coolant and the other had coolant that you can’t see 1/2 an inch deep through it. If not saltwater, what could cause that? I actually bought the kit from you guys planning to just do this myself, but when the coolant came out funky I decided I should have a shop do it and check them. I still plan to put them back together per the instructional videos you guys have put up.

Steve – one of them came out ok, the other was stuck in there pretty good per the radiator shop.

[Stephen Oliver]

What did they say was wrong with them? Look better than mine were and I had mine repaired.. did they have to smash them out of the housing or did they slip out ok?

Steve

[Tony Athens]

I’m confused– What do the aftercooler cores have to do with the coolant?

As to your coolant looking ODD, not sure if that is what salt water does.. I personally have never seen that from salt water intrusion..

Did the shop pressure test the Heat-Exchangers?

Who is putting your aftercoolers back together? Plenty of radiator shops have no clue on these unique designs although they always say they do.

Tony

[Leander Landrum]

Can anything other than the heat exchanger cause this to happen to coolant? I’m pretty sure this means there is salt water getting in to the coolant. The black part in my hand is just to show how opaque the fluid was. Other engine was very clear teal.

[Leander Landrum]

Went to the radiator shop this morning, turns out it was the aftercooler cores. Ordered a new set.

[Author]

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