Citric acid results

[les]

Rather disappointing ———-

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[svenedin]

The acton of citric acid can be very slow when cold. For an engine it really isn't practical to have a heated bath of it so I would suggest getting the engine running in the car and add citric acid to the coolant. Run up to temperature and repeat this several times then drain and flush.

I have de-rusted parts in a stainless steel preserving pan on the gas stove. It is very quick with the citric acid solution close to boiling. At garage temperature in autumn it takes weeks and even then I'll be agitating with a wire brush periodically as well.

Stephen

[les]

Thanks Stephen, the water solution was very hot when poured into the block, it’s been there for a total of 3 weeks, now looks like the surface of the iron has a film of some kind of crystalization, presumably from the acid. I’ve treated the head for 1 week and that looks fine.

[MinorOCD]

I agree with Stephen. You need to do it in an installed engine, a strong solution and leave it in for a week with plenty of heat cycles. My friend did his 1966 Austin Healey this year. It looked much like yours before hand, but 3 applications, a week at a time, cleaned it completely.
Paul

[svenedin]

Thanks Stephen, the water solution was very hot when poured into the block, it’s been there for a total of 3 weeks, now looks like the surface of the iron has a film of some kind of crystalization, presumably from the acid. I’ve treated the head for 1 week and that looks fine.

The trouble is that your hot solution would have cooled extremely fast with the heat sink of a cast iron block. The crystals look like limescale but they might be citric acid crystals. It will all dissolve with a hot solution and the water pump circulating the solution.

Stephen

[MinorOCD]

A Post script. He used 50g per litre of citric acid, the followed up with Sodium Bicarbonate to neutralise it, about 1.3 times as much per litre. The chemical reaction also created some agitation, which helped shift some residues…

[philthehill]

Les
I used citric acid on two 948cc Minor engines. Both were left soaking for approx the same time. One block came up like yours and the other is perfect.
My thought is that there has been a reaction to what was in the block i.e. type of anti-freeze for example to create the crystallisation.
I would suggest that you try Sodium Bicarbonate to neutralise as suggested by MinorOCD.
Phil

[les]

Thanks to all, well I refilled today hoping for a better result, thinking about it, that’s probably wishful thinking, so in view of suggestions maybe I’ll drain and try Sodium Bicarbonate. How is it used in this situation ?

[svenedin]

Sodium Bicarbonate is a weak alkali and will do precisely nothing for the engine deposits on its own. It can be used to neutralise the citric acid which will give a fizzing action.

Stephen

[59Elva]

Those deposits look similar to the green crystals I found in my water pump. I ordered citric acid after failing to find it locally. Arrived yesterday. I plan to mix some and add it to the cooling system then start and run the engine up to temperature each day next week. Flush with water then neutralize and flush again??
Any chemists out there? Is sodium bicarbonate best or sodium carbonate, or sodium hydroxide, or something else better? Will neutralizing leave a reactive salt that will attack the coolant or system components?

[svenedin]

There's really no need to neutralise with anything if the flushing is thorough. Citric acid is the acid that makes lemons sharp. It is widely used as a de-scaler for kettles, washing machines, dishwashers etc.

Stephen

[oliver90owner]

If planning on leaving citric acid solution in contact for some time, possibly at high temperature, just be aware of a) the radiator construction and b) its condition (particularly if it happens to be aluminium). Generally little problem - until the engine scale has been fully removed and excess citric acid remains.

At work they used to use an inhibited formic acid “traffic wash” for cleaning the delivery lorries and the works vehicles. It quite quickly removed the galv coating on the land rover trimmings.

[les]

Yes I am somewhat reluctant to use in a running engine regarding harm to aluminium and associated parts but the heat provided by such method and for a short period, may justify.

[Meggie moggy]

Hi I have read this with much interest as I feel Meggie may benefit from this.
To clarify the procedure in my simple head I
1) drain the coolant
2) replace with a citrc acid mix @ 50g/ litre
3) run the engine to temperature
4) continue to drive the as normal with mix in for a week( Meggie gets used regularly)
5) after a week drain the mix, flush through with clean water and refill with the citric mix for another week.
6) drain flush and if happy neutralise with Bicarbonate?

[MinorOCD]

Meggie,
Perfect summary. Depending on how bad the deposits will determine how many goes with the Citric acid you need.
Regarding Aluminium parts, my friend did his over about a month, with many heat cycles, and his aluminium parts (at least as many as the Morris) did not show any adverse affects,
All the best,
Paul

[les]

What a difference a day makes !! Referring to my earlier post, I drained the one day old citric acid intending to use some Sodium carbonate, when removing the water pump this is what I found.

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[taupe]

You must be chuffed with that!

Taupe

[59Elva]

Any explanation of what happened?

[les]

Well I am chufffed taupe, explanation wise I can only assume after draining out and flushing the 3 week old acid treatment, then, without much hope, put in another lot of citric acid, thought better of it, so after one day drained and flushed and result !

[philthehill]

Les
Well done.
That is how my 948cc block ended up. Nice, clean and rust free.
Phil