Will Holts Speed flush de crub my rawa water cooled engine?

[firstascent2002]

I want to flush through the raw water system on my engine this year as the amount of water coming from the exhaust is less than it used to be.

I have some holts speed flush (from halfords) but it does not say exactly what is in the stuff other than claiming it is safe for just about everything.

Anygood or should I get a central heating limescale remover?

J

 

[GSL]

What is the engine? More info is needed for a comprehensive reply.

It may take a lot of engineering to get Speed Flush to run through the system and catch it and recirculate it. Have you checked the blades on the impellor, maybe one is broken off and that will always slow down the water flow.

Gaham.

 

[firstascent2002]

The engine is a vp 2002.

I was going to catch the exhaust water in a bucket and and keep tolling up the intake bucket with that. tedious but easy

 

[VicS]

I want to flush through the raw water system on my engine this year as the amount of water coming from the exhaust is less than it used to be.

I have some holts speed flush (from halfords) but it does not say exactly what is in the stuff other than claiming it is safe for just about everything.

Anygood or should I get a central heating limescale remover?

J

No Speedflush would be a waste of time and effort.
Holts "Radflush 2 part" might be worth a try though. Part 1 is a descaler ( citric acid)

First thing though is the water pump impeller OK and is the exhaust injection point clear. One of those is more likely to be the cause of low total flow than scaling of the engine. Also check hoses for partial internal collapse.
Scaling of the engine may cause overheating but the full water flow should still go through the bypass.

I reckon an acid central heating boiler descaler, such as sulphamic acid based Fernox DS3, would be better than Rad flush. Alternatively Rydlyme marine descaler

If the system is really badly scaled and you are prepared to risk using it then a hydrochloric acid based brick and masonry or patio cleaner would be the most effective. ( they are not all HCl based though so you would have to check the labelling and possibly the MSDS)

 

[homa]

Rydlyme

I've used this stuff for the last couple of years to flush my small outboard, and Volvo 2002 at the end of the season.
It does exactly what it says on the bottle.
Best to have a recycling flushing system, i.e. catch the outgoing water from exhaust and feed back into sea water inlet, whilst runninmg the engine for a while.
Can highly recommend the stuff.

 

[electrosys]

Do be advised that Rydlyme is 10% hydrochloric acid - although it's described as 'hydrogen chloride, aqueous' (same thing !) in their H&S sheet - so it's not actually as 'safe' as the manufacturers would like you to believe.
It might be cheaper to buy patio cleaner and dilute it if necessary.

 

[VicS]

Do be advised that Rydlyme is 10% hydrochloric acid -

If it is simply 10% HCl they could not possibly describe it on the MSDS as non corrosive, nor claim that it is compatible with the range of materials they say it is!

I suspect it is hydrochloric acid based but buffered to a higher pH ( said merely to be <3) by the addition of organic salts. That would not be so in the case of a hydrochloric acid based brick, masonry or patio cleaner.

 

[saltyrob]

Hi,

I dissolved Fernox DS3 in warm water and pumped it into the engine rather like anti freeze and left it for 30 mins or so.Then flushed through with fresh water and repeated process.Loads of white stuff came out and I did not think the tiny amount of solution pumped into the tidal river would be an enviromental problem. Same engine ,raw water cooled vp2002.

Rob

 

[electrosys]

If it is simply 10% HCl they could not possibly describe it on the MSDS as non corrosive, nor claim that it is compatible with the range of materials they say it is!

I suspect it is hydrochloric acid based but buffered to a higher pH ( said merely to be <3) by the addition of organic salts. That would not be so in the case of a hydrochloric acid based brick, masonry or patio cleaner.

I refer you to:
http://www.chemtexcorp.com/docarchi...Exploding the Myth of Safe Scale Cleaners.pdf

If Dydlyme is non-corrosive - why do they warn (MSDS, June 2005):
"Spills and Disposal: Prevent any spilled Rydlyme from entering the storm water system. If a spill occurs use an inert absorbent such as vermiculite, sand or soil to absorb the spilt Rydlyme. Collect the absorbed material and place in a sealable container for appropriate disposal. Neutralization of the residual Rydlyme can be achieved by the addition of sodium bicarbonate."

And, (MSDS, Jan 2005):
"Do not circulate material for more than a six-hour period without consulting the manufacturer."

It has a claimed pH of 1 - 1.2 (MSDS, June 2005), but was found to be pH 0.1 when tested by Chemtex. Corrosive substances are defined as being aqueous with a pH of equal to or less than 2, or with a pH equal to or more than 12.5

 

[VicS]

That puts a different slant on it.
I had not come across the MSDS stating a pH of 1-1.2 , only this rather meaningless <3, and I'd found several versions. A pH of 1 might have rung some alarm bells although HCl only has to be 0.1 molar (0.36%)to be as low as that so it would not have been a very loud alarm bell. To put some sort of perspective on it the pH in the stomach is between 1 and 2, due mainly to hydrochloric acid.

According to EU classification hydrochloric acid is classed as corrosive if above 25% . (Corrosive meaning may destroy living tissue) Between 10 and 25% it is only classed as irritant. Rydlyme can hide behind that I guess if it is only 10% HCl. At least in the EU

I'd like to see some independent report on it rather than one produced by a competitor producing a similar descaler.

Pity I am no longer in a position to get some and give it to the analytical chemists to look at. I am sure we could have invented some plausible reason for them to do so.

It would also be interesting to do some laboratory tests to determine its effect on common metals found in engines and cooling systems .. aluminium in particular, esp as they suggest it can be used for descaling outboard engines.

 

[electrosys]

Hi VicS - you clearly know what you're talking about, so it's pity you're not still 'in the loop' as it were.

I found an interesting thread over at:
http://www.sailnet.com/forums/diesel-engine-forum/62599-how-clean-heat-exchanger-core.html which reads:
"My company does industrial heat exchanger cleaning, so I thought I could add some input...

lancelot9898 is doing it "right". If you are going to use acid, do a "quick" cleaning with acid (minutes, not hours or days!), rinse, soak in a baking soda bath to neutralize any remaining micro-pockets of acid, rinse again.

Although acid is not compatible with aluminum, copper, or brass, short contact times should not significantly affect the metal. Especially if you have scale coating the tubes already.

Rydlyme is an interesting product. I do NOT agree with their claims that it is "non-corrosive" nor some of their other claims. They claim the pH is "unreadable, generally <3". We've tested it at <1 pH and their literature raises enough red flags that I consider the product to be misleading at best. [which is pretty much my view]

I'd use a 10% - 20% solution of muriatic acid (available from Home Depot in the pool section), and be sure to use nitrile gloves, goggles, etc. Be safe!)"


I'm sure that Rydlyme does the job ok, but if you Google around a widespread opinion has developed that the product is completely harmless - some even say it's non-acidic ! Now that's worrying.

One other concern is that the manufacturers claim that it's safe to ingest, or pour into a water course even in concentrated form, yet they don't supply any LD50 data.

There's a competitive product called 'Blow Out', which appears to be an environmentally-friendly non-acid descaler: http://www.enviromfg.com/products_blowoutmarine.htm
They give LD50 data for rats as well as Brown Trout etc.
But - dunno if it can be sourced in the UK though .... might be worth enquiring ? No connection etc ....

 

[Slow_boat]

I used boiler de-scaler in my old Bukh last year. I left it in for at least a week with no apparant harm to the engine.