Clearing choked waterways

cliff

cliff

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Descaling choked engine cooling waterways

Has anyone any experience of cleaning the deposit out of the waterways on raw water cooled engines? The usual method of running the engine on boiler descaler (Fernox©) is not going to work this time as it appears the ports between the head and the exhaust manifold are solid salt. Engine runs a little hot but does not overheat so I though of perhaps running vinegar (acetic acid) through the system, collecting the coolant at the exhaust and recycling it back through the engine. i don't fancy using Sulphuric or Hydrochloric or Nitric as those would attack the cast iron block.
I looked at removing the exhaust manifold but for a number of reasons that is not really an option at this stage.
Any constructive comments welcome.
 
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Don't dismiss hydrochloric acid too quickly - if your engine is raw water cooled then rust will also be a component. I used it to flush through my ancient MD7A and removed huge amounts of crud, very effective and well worthwhile. I wouldn't worry too much about any effects on the cast iron block as they will be insignificant in such a short period.
 
Hi

I had partially blocked water ways on an VP MD11c (raw water cooled). I tried the usual Fernox treatments but didn't help much. I eventually took the head and cylinder blocks off and scraped the crud out of the waterways. I used small drill bits just turned by hand to ream out the holes, and kept going up a drill size until I got to metal. Some of the holes were about 3mm and eventually opened up to 8mm with the crud removed.

Engine ran much cooler afterwards. The only down side was the cost of the gasket set from VP.
 
Had excellent results with removing cylinderhead and manually rodding/poking/scraping waterways clear on a Yanmar 1GM10.Probably not much use if you're not a semi competent home mechanic as I would imagine paying someone to do the job maybe upwards of £200 inc new gaskets ect on a wee single cylinder diesel but does guarantee the water passages are clear.
 
DavidGrieves said:
Hi

I had partially blocked water ways on an VP MD11c (raw water cooled). I tried the usual Fernox treatments but didn't help much. I eventually took the head and cylinder blocks off and scraped the crud out of the waterways. I used small drill bits just turned by hand to ream out the holes, and kept going up a drill size until I got to metal. Some of the holes were about 3mm and eventually opened up to 8mm with the crud removed.

Engine ran much cooler afterwards. The only down side was the cost of the gasket set from VP.
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I had the head off my 3GM30 - and the exhaust manifold as well. I discovered that warm water & vinegar generated a lot of effervescence - with just the thermostat!. So once I've buttoned her all up again I'm going the closed cycle - let it warm up a little vinegar soak - route. I'm replacing hoses as well as a general re-vamp. I have 10l of vinegar to get on with.. :p
Apertures in the head gasket were the same size as the block /head - so nothing serious to dig out there as it turned out. The exhaust manifold was clogged up - on the water side only. Rotary wire brush / careful use of electric scraper cleared out all that lot.
I suspect Yanmar gaskets are about as scary as they get price wise, but having done the work I don't want to be going back in there too often, so the £90 or so for parts I don't grudge much.

Graeme
 
50 beer tokens for 5l of rydlyme? oh, er missus. might try cillet bang limescale remover first failing that bite the bullet and pull the exhaust manifold and put the tokens saved towards manifold gaskets.
 
Update for all you tight-wad sailors.
Waterways now spotlessly clean and engine running cooler than it ever has in the past 10 years - no dismantling apart for removing the thermostat and a couple of bypass hoses.
Procedure:
Remove hose between thermostat housing and the injection point on the exhaust manifold - attach temporary hose to injection point on exhaust manifold - attach other end of hose to an inline submersible pump and drop the pump over the side. This provides cooling water to the exhaust.
Remove thermostat
Pinch off hose between cooling water pipe and thermostat housing
Refit housing using temporary gasket (originally sealed by rubber ring around thermostat)
Remove engine anode and blank off the hole (old anode carrier used as blanking plug.
Remove sea water piping from engine driven seawater pump inlet - attach length of hose to the pump inlet placing the other end in a 3 gallon bucket.
Attach hose to the outlet on the thermostat housing and run back to the bucket - If one uses clear plastic tubing here one can see the crud coming out of the engine.
Pour 2 gallons of fresh water into the bucket, start engine, switch on the inline sea water pump (exhaust cooling).

The engine will now be circulating fresh water round the block, head, exhaust manifold, through the stat housing (thermostat previously removed) and back to the bucket.
As there is no engine cooling as such the temp will rise - once it gets to around 40°C add ½ litre (500cc) of 44% phosphoric acid to the bucket and watch the crud coming out.....
The discharge back to the bucket will contain lots of bubbles as the acid does its job dissolving the lime scale and salt deposits.
I ran my engine for ~20 mins adding a gallon of cold water as the temperature rose. After about 15 minutes the bubbling had all but stopped indicating either all salt was gone or the acid was spent (done / used up).
A sample of the acid solution was added to some sodium carbonate and the subsequent reaction indicated the acid was still of working strength.
More sodium carbonate was added to the bucket until there was no further reaction (acid spent / neutralised)
The engine was shut down and the discharge tube between the thermostat housing and the bucket was removed as was the temporary exhaust cooling water hose and the original hose refitted - discharge from the engine would now go down the exhaust.
The engine was restarted and the bucket continually topped up with fresh water thereby flushing any remaining salt out of the block.
Once flushed the stat was replaced and remaining hoses returned to their original configuration and the engine anode refitted.
Subsequent running of the engine under load was satisfactory.

Now the crunch - acid (sold as Scale-X) was obtained from www.taylormclure.co.uk
I used 500cc only (bought 5L)
So 10+ flushes for around 30 beer tokens as against 50 beer tokens for what might have done one flush so I guess I will not be buying any rydlyme in the near future.

As a side line Phosphoric Acid is also used in Naval Jelly, Kurust and other "rust converters".
 
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A sample of the acid solution was added to some salt and the subsequent reaction indicated the acid was still of working strength.
More salt was added to the bucket until there was no further reaction (acid spent / neutralised)
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Sorry I dont understand your reasoning here.

What reaction did you observe between salt and the acid that indicated that the acid was still of working strength ?

How does adding salt to the acid neutralise it ?

Did you mean to say soda ( sodium carbonate ) rather than salt ?
 
VicS said:
Did you mean to say soda (sodium carbonate) rather than salt?
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Ooops - yep - Sodium Carbonate - Please forgive me Vic, I am only a Metallurgist not a Chemist though in my defence I always thought Sodium carbonate (also known as washing soda or soda ash), Na2CO3 was a sodium salt of carbonic acid.
 
pampas said:
Rydlyme is not used in the concentrated form, so 1 ltr will do many flushes>
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How many? what concentration is used? The Rydlyme website indicates it is (or can be) used in the neat form it also indicates in the MSDS ambient temp circulation for 2~4 hours with an upper limit of 6 hours.
 
I had exactly the same problem with my 1GM10 on Hunter 245. Over heating when running at reasonable revs. I tried Rydlyme with little effect the first time then used 1:1 and left it over night. When I started the engine it clreared out loads of white chalky looking crud and would not overheat. However we removed the head (not me but someone I paid) and cleared waterways and now it runs runs perfectly. The gasket was about £25 and for peace of mind well worth doing.
I would recommned Rydlyme.
 
Derm said:
I had exactly the same problem with my 1GM10 on Hunter 245. Over heating when running at reasonable revs. I tried Rydlyme with little effect the first time then used 1:1 and left it over night. When I started the engine it clreared out loads of white chalky looking crud and would not overheat. However we removed the head (not me but someone I paid) and cleared waterways and now it runs runs perfectly. The gasket was about £25 and for peace of mind well worth doing.
I would recommned Rydlyme.
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Hmm 50 beer tokens for something which in your own words had little effect first time round then using a 1:1 mix and overnight soak before the waterways were partially cleaned then add another 25 tokens for a head gasket plus cost of labour to finish the job manually - yep sound like a good deal - not - £225~250+? to descale the waterways? - does not sound like a good deal to me. I think I'll stick to using dilute phosphoric acid costing maybe £1.50 per flush (I used too much first time round - a 2% soln should be sufficient)
 
Personally I use 1 to5 parts water and circulate with an old 12v. pump. This winter I series`d up the MD7a to the BMC commander, bypassed the water pumps on both engines, ran when on board for about 3 days ("hours/day) before the solution was spent, used the small engine strum with filter removed. into BMC suction ,its exhaust injection returned to small engine, strum box. used garden hose and wooden hose adaptors made, simple and easy to use. Thermostat on the volvo now works and its block runs cool, does the job it was intened to do and no fear of acid burns with and slashes useing this product. worth the money just for the safety and no need to flush after use.
 
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