Heat exchanger - how bad is it ?

[TopperHarley]

Hi Folks,

Today I checked the zinc on the heat exchanger for the first time on my new (to me) Catalina 30 Universal M25XPB. The engine is about 3 years old, done 200hrs.

Im unsure of the previous owners standard of maintenance, hence wanting to check the zinc ASAP.

My previous boat was raw water cooled so im not that familiar with HX's.

The entire zinc was gone and the picture looked something like this:



My question... how bad is this ? (I have no overheating symptoms)

Cheers.

[DougR]

The condition of the HE isn't too bad, as evidenced by the fact that you have no overheating problem. But it is hard to see the lower left portion of the tube bundle....

But while you have it open, you mind as well go ahead and clean out the tubes. Go to a welding supply store and buy a 1/8 inch diameter bronze brazing rod that is not flux coated. Cut this off to a length slightly longer than the HE is long, plus enough to bend a loop handle in the end. You can use this rod to run down the tubes and clean any debris out of the tubes. This assumes the tube diameter is about 1/8 inch. If the tubes are larger, say 1/4 inch, you could get a larger rod, or even use a barrel cleaning brush from a .22 caliber rifle cleaning kit.

Flush out the debris both forward and backward with a dockside hose, put in a new zinc, and you are set to go.

DougR

[TopperHarley]

Thanks Doug!

[TopperHarley]

Can anyone suggest a flush or rinse treatment that I can run through the heat exchanger without having to remove it?

I'm not confident of 'burping' the coolant system if I remove and replace the HX!

Cheers

[Wotname]

Originally Posted by TopperHarley

Can anyone suggest a flush or rinse treatment that I can run through the heat exchanger without having to remove it?

I'm not confident of 'burping' the coolant system if I remove and replace the HX!

Cheers

Assuming you are wanting to clean the raw (sea) water side of the HX, I would suggest flushing the raw water side with common vinegar as one might do with a raw water cooled engine.

Use say 8 litres (1.5 gallons) in a bucket and plumb into the rawvwater entry of the HX with the outlet of the HX going back to the bucket. Use a pump of your choice to circulate the vingear for say 12 or 24 hours.

A small electric bilge pump is as good as any.

If you want to dot the eyes and cross the tees, back flush briefly at the end while discarding the back flush vinegar.

[Rustic Charm]

Perhaps I'm missing something in seeing this picture, but what I'm seeing is a fairly seriously blocked HE. The bottom half look totally blocked. If that's the case you need it thoroughly cleaned, if it's not too late.

Who say the zinc was gone completely, that's not a good sign.

What is the engine this is from?

Postscript lol, just realise it's a Universal which I'm completely unfamiliar with.

[SorinCT]

Heat exchangers should be cleaned once every few years by chemical re-circulation (if possible) or by mechanical methods. All tubes should be checked for plugging and drilled if necessary. A pressure test should be carried out when done.
Recommended cleaning chemicals are hydrochloric acid or sulphamidic acid. They are commonly found by the name of Descaling Liquid or Descalex powder.

[a64pilot]

You can take it to a radiator shop, they will clean it clean as a whistle for very little money, I believe they boil radiators in some form of acid bath.
I believe they should be disassembled every now and again as it's the only way to truly clean and inspect the thing.

[Lepke]

I use RYDLYME for both the salt and fresh sides. It seems to clean better than the radiator cleaners. I put a pump in a 5 gallon bucket and make temporary connections so I can circulate for a couple hours. With 2 gallons, I can clean both mains, salt and fresh. You can also use it for soaking. It's not an acid, you can get it on your skin. In most places you can dump it overboard or dump into the local sewer system. Biodegradable, non-toxic.

[Orion Jim]

Originally Posted by a64pilot

You can take it to a radiator shop, they will clean it clean as a whistle for very little money, I believe they boil radiators in some form of acid bath.
I believe they should be disassembled every now and again as it's the only way to truly clean and inspect the thing.

This is excellent advice. Quick, cheap, effective. Carefully inspect. Mine had a tiny crack in the end plate. Give it a coat of paint while its out and you're good for several years with any luck.

[Jim Cate]

Give it a coat of paint while its out and you're good for several years with any luck.

Paint a heat exchanger bundle??

Jim

[leftbrainstuff]

Originally Posted by TopperHarley

Can anyone suggest a flush or rinse treatment that I can run through the heat exchanger without having to remove it?

I'm not confident of 'burping' the coolant system if I remove and replace the HX!

Cheers

Rod it out. 1/8" ss tig welding rod works a treat.

Chemical clean with hot caustic. But dont leave it in the bath for too long.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Wotname]

Let's not forget the OP is looking for ways to clean his HX without removing it or disturbing the fresh water / coolant side.

[Greatketch33]

Originally Posted by Lepke

I use RYDLYME for both the salt and fresh sides. It seems to clean better than the radiator cleaners. I put a pump in a 5 gallon bucket and make temporary connections so I can circulate for a couple hours. With 2 gallons, I can clean both mains, salt and fresh. You can also use it for soaking. It's not an acid, you can get it on your skin. In most places you can dump it overboard or dump into the local sewer system. Biodegradable, non-toxic.

Note: Rydlyme can pit aluminum.

[ranger58sb]

Originally Posted by TopperHarley

Can anyone suggest a flush or rinse treatment that I can run through the heat exchanger without having to remove it?

I'm not confident of 'burping' the coolant system if I remove and replace the HX!

Cheers

Rydlyme, Barnacle Buster, or Triton Marine Green (or something like that).

-Chris