Hydrocchloric Acid Cleaning

[Little Dorrit]

What are the risks and dangers of cleaning my engine water cooling system (MD5A seawater cooled) with hydrochloric acid? I ws going to block up the exhaust outlet and fill up the cooling system with hydrochloric acid and leave it a day or two...and then flush it out.

 

[nigelmercier]

What are the risks and dangers of cleaning my engine water cooling system (MD5A seawater cooled) with hydrochloric acid? I ws going to block up the exhaust outlet and fill up the cooling system with hydrochloric acid and leave it a day or two...and then flush it out.

After a day or two, you may not have anything left to flush it out of!

Dilute it to between 2% and 5% and leave it an hour or so. Drain it out and test on a bit of lime scale, if it doesn't fizz, it has been neutralised so there is more lime scale in the engine. Repeat if no fizz. FLUSH!

 

[AllanJ]

After a day or two, you may not have anything left to flush it out of!

Dilute it to between 2% and 5% and leave it an hour or so. Drain it out and test on a bit of lime scale, if it doesn't fizz, it has been neutralised so there is more lime scale in the engine. Repeat if no fizz. FLUSH!

Dim thoughts of third-year chemistry, but
http://www.launc.tased.edu.au/online/sciences/PhysSci/pschem/acidbase/acidRxns.htm
Care!

 

[Little Dorrit]

Thanks for that the acid I have is probably diluted a little but I'll test it out first. I was just wondering if there were any parts of the system that may get totally dissolved the expansion chamber for example?

 

[Little Dorrit]

what does all that mean??

 

[AllanJ]

It means that HCl will be busy converting any metal to a salt. That is why Nigel says that constant, concentrated, use will leave you with nothing to clean out.
No matter what you do with HCl, you will be affecting the metallic parts. I am no expert in cleaning out engines, but I do know some chemistry. Just trying to help.

 

[BlueChip]

I wouldnt use hydrochloric acid anywhere near my engine, if you want a descaling acid get something like Sulphamic Acid which is much less aggressive yet very effective and widely used in industry for this application.

 

[Little Dorrit]

Thanks - I'll probably give it a miss then!

 

[mitiempo]

Use rydlime. Safer than hydrochloric acid.

 

[vyv_cox]

Dilute hydrochloric acid has very little effect on iron/steel and it is perfectly safe to use it in most engines. Remove the thermostat and anodes. Diluting it excessively will remove the effects you are trying to achieve - you cannot buy it in a concentrated state. Buy HCl based brick cleaner (there are other types) from a builders merchant and use it as it is. No reason to leave it for a long time, it will do its job in about 10 minutes.

Rydlyme is often recommended for the job although I have never used it. I have used hydrochloric acid several times, very successfully, in engines and in toilets.

 

[Little Dorrit]

Remove the thermostat and anodes.

Yes the thermostat has wax in it...so that makes sense.

 

[VicS]

Yes the thermostat has wax in it...so that makes sense.

why ?

 

[VicS]

Use rydlime. Safer than hydrochloric acid.

But just what is Rydlyme ??

.

 

[Liz_I]

Hydrochloric Acid works absolutely brilliantly on copper & steel but whatever you do DO NOT let it come into contact with any aluminum. We speak from bitter experience.

Great for the loos too!

 

[MM5AHO]

As said above, HCl will clean out limescale and not have much effect on the metal of the engine, other than removing oxides perhaps.
In the galvanzing industry, thousands of tonnes of steel are immersed in HCl of strength between 3 and 18% for typically 2-6 hours without any discernable effect.
Its also possible to get a metal inhibitor to add, so that leaving the acid for days at a time is possible. But you don't need that for this job.
Its a time and concentration issue. If the acid is so strong as to fume and be difficult to use, then maybe too strong.
If you leave it there for hours, then too long.
But weak strength for 10-20 mins, no problem.

 

[Little Dorrit]

I assumed that was the only reason to take out the thermostat...otherwise why remove it?

 

[sarabande]

Rydlyme

Here's the MDSS

http://www.rydlyme.com/pdf/RYDLYME U.S. MSDS Aug 2009 REVISION.pdf

 

[mitiempo]

Because removing the thermostat it clears the passage. The impeller should be removed as well.

 

[mitiempo]

More information from the same site.
http://www.rydlymemarine.com/
http://www.rydlymemarine.com/success.html

 

[alan_d]

Bukh Engines

A warning for anyone with a Bukh engine: the manufacturers apparently advise against using HCl in their engines because of possible damage to the seals of the wet cylinder-liners.