Coolant System Flush

[Eric22]

I'm wondering if anyone has ever tried to flush the heat exchanger and fresh water side of an engine with vinegar. I'm thinking that since it does such a good job of dissolving calcium and other deposit in fresh water plumbing systems, that pumping some in and letting it sit for 24 hours might be a good idea. I know the exchanger is getting clogged so I need to do something here.

If anyone has tried it, let me know if it worked and if there were any problems. Thanks! Eric

[a64pilot]

Fresh water side of the engine is almost identical to an automotive engine.
Vinegar wouldn't likely cause any harm, but may not be very effective either. I'd use a product manufactured for flushing radiators and follow directions. Usually an acid with a neutralizer.
Myself I've never had to use a flush, just flushing well with pure water has always been enough, but if you have a problem, you may have to try something more aggressive.

[Eric22]

Actually, I meant the raw water side where it goes through the heat exchanger and muffler. I'm sure there is salt and maybe calcium build up that I think would respond well to a 24 hour or so vinegar bath. Think I'm going to try it. Thanks.

[a64pilot]

Originally Posted by Eric22

Actually, I meant the raw water side where it goes through the heat exchanger and muffler. I'm sure there is salt and maybe calcium build up that I think would respond well to a 24 hour or so vinegar bath. Think I'm going to try it. Thanks.

Doubt it would hurt anything to try and may help, but I think the usual way is to dis-assemble the heat exchanger and take it to a radiator shop.

Are you having overheating problems now?

[DeepFrz]

Probably a good idea to disassemble the heat exchanger, as a64pilot says, and the exhaust elbow if you haven't done that for a while.

[Eric22]

I don't have a temp. gauge, but the engine feels too hot. I also think I'm getting less flow than I should. But, I don't want to mess w/the exchanger or elbow so I thought I would give this a shot first - just wondering if there are any real downsides I'd not thought of. I wonder if vinegar dissolves rust?

[DeepFrz]

Flushing the raw water system wont flush the injection elbow. Removing and cleaning properly, although a PITA, will give you a better sense of knowing the cooling system is working as it should. Also flushing the heat exchanger may not clear out any broken off impeller pieces that are inhibiting the flow.

[thinwater]

Originally Posted by Eric22

I don't have a temp. gauge, but the engine feels too hot. I also think I'm getting less flow than I should. But, I don't want to mess w/the exchanger or elbow so I thought I would give this a shot first - just wondering if there are any real downsides I'd not thought of. I wonder if vinegar dissolves rust?

a. Get a temperature gauge? "Feels hot" is not useful information.

b. It seems you've already decided vinegar is the right answer and you are looking for confirmation, not information. If vinegar is not the consensus, what will you make of that?

Any acid cleaner will dissolve calcium, rust and all metals at some rate. The challenge is to pick a compromise you are happy with. There are commercial products and you will need to read the instructions. However, as Deepfriz implied, it is common for the deposited to be heavier is certain locations (heat encourages the calcium to come out of solution). If you use enough acid to treat the heavy spots, you may eat a hole somewhere else.

TANSTAFL

[CS Cruiser]

Google this RYDLYME MARINE, that's what to use.

[darylat8750]

Originally Posted by Eric22

I don't have a temp. gauge, but the engine feels too hot. I also think I'm getting less flow than I should. But, I don't want to mess w/the exchanger or elbow so I thought I would give this a shot first - just wondering if there are any real downsides I'd not thought of. I wonder if vinegar dissolves rust?

As someone else said "Feels too hot" is not very useful. An IR gun, hand held is very handy to have on a boat. Here is one from Sears but Home Depot, Menards, Lowes, NAPA all have something similar.
Sears.com

On most marine engines the place the raw water is injected into the exhaust is considered a consumable. When it goes completely it is a real irritant. I would take it off, clean, inspect and repair or replace as required. Also cleaning the heat exchanger is not that big a deal if you can remove a radiator from an old tractor you can take this off and clean it yourself or have it cleaned. These are "Pay me now or PAY me later" things.

If you don't want to take off the injection elbow because the bolts are rusty all I can say is it will only get worse if you procrastinate.

[thinwater]

Originally Posted by darylat8750

As someone else said "Feels too hot" is not very useful. An IR gun, hand held is very handy to have on a boat. Here is one from Sears but Home Depot, Menards, Lowes, NAPA all have something similar.
Sears.com

Two thumbs up. A very handy diagnostic tool, for everything from engines, HVAC, freezers, insulation, drafts, to home ovens.

One tip: they are not AT ALL accurate on shiny surfaces, like SS or aluminum, because they are calibrated based upon black body emission. They can be off by 50-100 F on a chromed exhaust or SS fitting. A spot of black spray paint solves the problem (common to see black dots on SS equipment in refineries from this practice).

[charliehows]

hi Eric, I posted this (see below) a few days ago - no responses so im guessing nobody on here has much of an answer for either of us. I was thinking about trying vinegar myself as the hydrochloric acid is a bit - unpleasant although at 5% I didnt have any ill effects from having my hand in the bucket up to the elbow last time - dont try this at home, mind you (i'm a rhinoceros when it comes to that sort of thing). As suggested by others - cant see any problem with trying vinegar but im also not sure its the right acid.

I'd agree with a couple of the suggestions above, to dismantle the unit and have a damn good look at it - the other suggestion i'd make - if you cant afford an IR gun you can get a coffee milk temp gauge from any decent kitchen shop for $10 - thats what i use because the ideal temp for a good latte is about the same as the ideal operatiing temp for a raw water cooled engine - yours will probably run a bit hotter, you should find the operating temp and get something to gauge it - if not for peace of mind then for the simple reason that an overheating engine will destroy itself pretty much quicker than almost anything else that can go wrong.

my post;

done a bit of a search but couldnt find much - an old Yanmar expert told me to flush the engine via the input hose with a bucket of 5% ish dilution of hydrochloric acid every couple of years. I did it a few years ago but I dont really fancy doing it again - is there any other way to clean salt and buildup out of the water galleys? I came back from a month away recently and the main feed into the engine had silted up and concreted, sending all water to the startup by-pass - had to give it a good poking with a bit of wire to get water into the engine again. The eng. is a yanmar 2qm20, I pulled the anode galleys and she doesnt look too bad inside, there doesnt seem to be so much crap buildup if you change the anodes fairly frequently, but the blockage to the engine has me a bit worried.
__________________

[ranger58sb]

Eric, there are three products specifically formulated for environmentally-friendly descaling: Rydlyme Marine, Barnacle Buster, and Triton Marine Green (or something like that). Don't know about vinegar. I'm using Rydlyme, as we speak.


I've done one engine, with underwhelming results... but I also found (after the fact) a flaw in my method. And I'm also doing this as en experiment, not because our engines are showing signs of needing it. The latter means that I didn't see any appreciable drop in temps, but then I also didn't know whether our heat exchangers even needed it.


I'm doing the second engine just now, using a different technique, and I may be able to better evaluate the outcomes afterwards, especially if I see any temp differences.


The process can be either fill-wait-flush, or recirculate. How you do it will also influence whether you should remove impellers and zincs first...


-Chris

[osirissail]

Although not mentioned yet - insufficient raw water flow through the system of pipes and H.E. and sometimes the Exhaust Manifold jacket is a major safety item.

The concern lies in the rubber exhaust hose we use to connect the engine exhaust to "over the side." That rubber exhaust hose - rigid or flexible - can only tolerate temperatures below 200°F before it starts to get "cooked" and brittle.

Basically you have hot exhaust flames/gases coming out of the exhaust manifold into your riser and then into the rubber exhaust hose. Raw water is injected into the exhaust gas path to try to keep the temperature below the limit. If, when the engine is running, you cannot put your hand on the hose without getting burned you most probably have insufficient raw water flow and need to find the problem and fix it.

Normally, the #1 cause is a corroded and partially closed exhaust water injection elbow. But other problems from broken impeller vanes to clogged H.E. tubes to exhaust manifold jacket corrosion can restrict the water flow.

The safety hazard is a ruptured rubber exhaust hose inside the boat which will spew hot exhaust gases and steaming salt water all over everything. It makes a serious mess and as in my case only happens just when you "have to" have the engine available.

So borrowing an IR or other temperature guage/sensor tool to check your exhaust hose temperature is well worth the trouble.

[charliehows]

A strong acid is one in which the molecules present practically all ionise when placed in water, e.g. hydrochloric acid, HCl.

• A weak acid is one where only a small proportion of the molecules ionise, e.g. acetic acid (ethanoic acid), CH3COOH.
  
  
• If you prepare 0.1 M solutions of each you should find the hydrochloric acid has a pH of 1 corresponding to a [H+] = 10-1 = 0.1 M. That is, practically every HCl molecule has ionised, producing a H+.
  By contrast a 0.1 M solution of acetic acid will have a pH close to 3 indicating a [H+] close to 10-3 = 0.001 M. Only about 0.001 / 0.1 = 1% of the acetic acid molecules have ionised producing a H+.

vinegar typically contains about 5% acetic acid. My guess would be the 5% dilution hydrochloric acid recommended by my Yanmar guy would be quite a bit stronger than vinegar, but leaving the vinegar in the engine for a longer period would make up for that, whilst being a more benign acid to handle.