Engine Heat Exchangers

[steve77]

I have a Yanmar 4JH3-HTE. There are three tube and shell heat exchangers on this engine - one for the engine coolant (Yanmar calls this the fresh water cooler), one for the turbo intercooler, and another for the lube oil cooler.

When I read about people cleaning the "heat exchanger" on their engines, they are talking about the fresh water cooler. I have not heard much about the intercooler nor the lube oil cooler. It seems that these would also need cleaning with the same frequency.

Is there something I'm missing? Thanks!

Steve

[capt jgw]

If any of them have sea water flowing through, then yes the cleaning schedule should be the same as the main hx. But many of the auxiliary coolers are fresh water (coolant) fed so they hardly ever, if ever, need cleaning. I recently read a post, don't remember which forum, about undersized heat exchangers and overheating. One responder said he switched his oil cooler from coolant fed to sea water fed and his overheating problem ceased. But he would now have to clean it like any other sea water fed cooler.

[DougR]

Nope, you aren’t missing anything..... If all of your coolers are sea water cooled you should clean them at about the same frequency as your heat exchanger.

Your aftercooler/ intercooler should be cleaned on both the seawater side and also on the air flow side. The tube bundle/ element needs to be removed from the housing periodically and cleaned, because turbos tend to emit oil when run at no or low boost levels, and this oil finds its way onto the aftercooler fins, gumming them up. Condensate can also form when the turbo compresses moist air, and this can collect on the fins. The combination of oil and water deposits on the fins lowers the efficiency of the aftercooler, and needs to be cleaned from time to time.

[steve77]

Originally Posted by DougR

Nope, you aren’t missing anything..... If all of your coolers are sea water cooled you should clean them at about the same frequency as your heat exchanger.

Your aftercooler/ intercooler should be cleaned on both the seawater side and also on the air flow side. The tube bundle/ element needs to be removed from the housing periodically and cleaned, because turbos tend to emit oil when run at no or low boost levels, and this oil finds its way onto the aftercooler fins, gumming them up. Condensate can also form when the turbo compresses moist air, and this can collect on the fins. The combination of oil and water deposits on the fins lowers the efficiency of the aftercooler, and needs to be cleaned from time to time.

Good information on the reasons for the need to clean the intercooler. Thanks!

And yes, all three of these heat exchangers are seawater-cooled. I neglected to include that in my original post.

Cheers!

Steve

[steve77]

Well, here is one reason to clean your heat exchangers. We have owned Orontes II for over ten years, and I have never lost an impeller blade. Was very surprised when I opened up the intercooler to see this. We are the second owners.

The engine never ran hot, even though it appears that over 30% of the tubes were blocked by impeller bits.

Steve

[Compass790]

Originally Posted by steve77

Well, here is one reason to clean your heat exchangers. We have owned Orontes II for over ten years, and I have never lost an impeller blade. Was very surprised when I opened up the intercooler to see this. We are the second owners.

The engine never ran hot, even though it appears that over 30% of the tubes were blocked by impeller bits.

Steve

Yes that's a good example, thanks for posting.
I'm cheap but I bought a strainer to go after the RW pump as I noticed a few impeller blades in the cooling galleries of our RW cooled engine when we rebuilt it. Found the mesh to be too small as it clogged with marine life but drilled a few 1/4" holes in it & no problems now.