18 replies to this topic

[Edington]

I am slowly recommissioning my son's mini Sky that has been standing for nearly 25 years. I was supposed to be foreman but have ended up doing the work! Unfortunately he didn't drain the coolant out of the engine and over time the coolant has evaporated leaving a combination of rust and other residue in the channels. So I'm going to remove and split the engine. Is there any solution I can use that will clean up these waterways? Has anyone done this before and was it successful? 

[nicklouse]

If you are taking the engine out and stripping it and have not done so yet putting something like ZEP (Screwfix) in for some time before you do split it. But when you do knock the core plugs out and blast it out.

[eric67]

On mine I removed the core plugs and water pump and then scraped and vacuumed out as much crud as possible. I then fitted temporary wooden blanks to all openings and used a citric acid solution to clean the waterways. It took a few attempts but came up really well.

[Spider]

I wouldn't be removing the engine at this stage, if it was only for this.

 

I've used a product called Liquid Intelligence with great success on several engines now. Some need 2 goes but it does the job. It's a step process and takes around a week - all engine in car. I'm not sure it's available in the UK though ?

 

https://liquidintell...em-cleaning-kit

Failling that, an acid similar to what Eric 67 used would be fine. Certainly the way he did would give quicker results, but even leaving the plugs etc in place, cleaning it as is until it was clean, then flushing and finally, replace the water pump, thermostat housing and any other alloy parts in the cooling system before filling with coolant.

 

I have also used molasses in the same way, that takes about 3 - 4 weeks.

 

Regardless which way you go, before starting, be sure the drain plug on the back of the block is clear and free flowing and if you have a plug on the radiator, same for that.

[Shooter63]

Oxalic acid works well and quick to remove rust, a quick Google will give you a steer, buy it in crystal form and dilute.

Shooter

[Bobbins]

I’ve just used Google to find a source of oxalic acid crystals and came across this …

“Oxalic Acid in its crystal form is now classified as a regulated poison and is no longer available for sale to the general public”

Damn, my block’s nearly fully stripped including core plugs and I did think a bath of oxalic acid might be very useful!

[ThermalEvent]

I used citric acid and run the engine up to temp, then let it cool and drain. Worst part was getting rid of the stuff as I must have flushed the cooling system 10+ times with clean water and each time it would still turn rusty orange.

Ended up putting the garden hose into the rad and thermostat housing to clear it all.

Did a very good job though! I've even used the stuff to clean the inside of a rusty fuel tank before sealing it with POR.

[Edington]

Many thanks for all the suggestions. I'm still going to take the engine out as the whole engine bay is a bit of a mess but nothing bigger than rust and spiders! As for taking the core plugs out it's something I've never done so possibly a daft question but how do they come out and replaced? I've taken a number of engines out but not an A+ with servo. Do I need to remove the servo to lift the engine out? 

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[Shooter63]

I’ve just used Google to find a source of oxalic acid crystals and came across this …

“Oxalic Acid in its crystal form is now classified as a regulated poison and is no longer available for sale to the general public”

Damn, my block’s nearly fully stripped including core plugs and I did think a bath of oxalic acid might be very useful!

I didn't realise it had gone over, I did find it strange that I couldn't buy another tub. You might want to try going to a "trade" site. It's the same with paint stripper, the only stuff that isn't some form of lemon juice concoction is only sold through the trade.

Shooter

[coopertaz]

no need to remove servo you can release master cylider from servo, 2 nuts, then gently ease out of the way when you raise the engine. also a good time to check master cylinde seals if there is any fluid on plunger

[84 City E]

 

I’ve just used Google to find a source of oxalic acid crystals and came across this …

“Oxalic Acid in its crystal form is now classified as a regulated poison and is no longer available for sale to the general public”

Damn, my block’s nearly fully stripped including core plugs and I did think a bath of oxalic acid might be very useful!

I didn't realise it had gone over, I did find it strange that I couldn't buy another tub. You might want to try going to a "trade" site. It's the same with paint stripper, the only stuff that isn't some form of lemon juice concoction is only sold through the trade.

Shooter

 

I believe its still sold as premixed 'brick acid' to the trade, relatively easily available on the usual places like amazon etc

[Shooter63]

I’ve just used Google to find a source of oxalic acid crystals and came across this …

“Oxalic Acid in its crystal form is now classified as a regulated poison and is no longer available for sale to the general public”

Damn, my block’s nearly fully stripped including core plugs and I did think a bath of oxalic acid might be very useful!

I didn't realise it had gone over, I did find it strange that I couldn't buy another tub. You might want to try going to a "trade" site. It's the same with paint stripper, the only stuff that isn't some form of lemon juice concoction is only sold through the trade.

Shooter

I believe its still sold as premixed 'brick acid' to the trade, relatively easily available on the usual places like amazon etc

I'm by no means a chemist but I thought brick acid was diluted sulphuric acid, another use for oxalic acid is as deck cleaner, I bought mine from an online yacht chandler.

Shooter

[Gaz66]

Caustic soda, if it's good enough for MED's blocks it's good enough for ours! 😁

[Bobbins]

Caustic soda, if it's good enough for MED's blocks it's good enough for ours! 😁

Used within the coolant jacket or can a bare block be immersed in a caustic soda solution?

[Gaz66]

Caustic soda, if it's good enough for MED's blocks it's good enough for ours! 😁

Used within the coolant jacket or can a bare block be immersed in a caustic soda solution?

In one of MED's YouTube videos he says the whole block is caustic dipped after removing gallery plugs and core plugs.
Not sure what this would do to alloy bits like water pump if it was run as a temporary caustic coolant.

Edited by Gaz66, 29 October 2024 - 11:43 PM.