Cleaning cooling system hack

[Stevie R]

I’m not sure if someone is pulling my leg but I’ve been told if you want to clean out your cooling system effectively drop a dishwasher tablet in the radiator and run the engine until hot this will clean the system thoroughly,
Anyone else tried this?

[Myrtles Man]

Dunno about dishwasher tablets but for a pretty heavy-duty cooling system clean out check this video from 10.27 on...

https://www.youtube.com/watch?v=Kpf91W9mbqw

[svenedin]

Dishwasher tablets are strongly alkaline. That helps get rid of greasy food residue but it won’t help at all with limescale deposits in a cooling system. Strong alkali is unsafe on aluminium and there are aluminium alloy parts in the cooling system. I would definitely not put dishwasher tablets in the cooling system. Instead, you can put an acid in the cooling system, citric acid. This works really well.

Stephen

[myoldjalopy]

Can you put citric acid in the dishwasher?

[svenedin]

Can you put citric acid in the dishwasher?

Yes! Not to clean dishes but to clean the machine. Also brilliant in the washing machine and kettle. Cleans limescale off the heating element and from inside pipework.

Stephen

[michael4]

Unusually I went for the expensive option, Prestone cooling system flush. Certainly does the job and does not appear to have found any leaks, yet.

I didn't realise, Prestone is part of Holts.

[Mervin]

When I owned a Traveller, years ago, the rear of the engine block was full of rust and sludge. The block drain was blocked solid too (no pun intended!). Detected when the cyl. cover was removed for an overhaul.
Following a recommendation, I used a liquid kettle descaler poured into the cooling passages on the block's surface. It did a good job helped along by agitation using the end of a steel coathanger. No casting was harmed during the process.
Others might disagree and criticise, but it worked for me.

[svenedin]

When I owned a Traveller, years ago, the rear of the engine block was full of rust and sludge. The block drain was blocked solid too (no pun intended!). Detected when the cyl. cover was removed for an overhaul.
Following a recommendation, I used a liquid kettle descaler poured into the cooling passages on the block's surface. It did a good job helped along by agitation using the end of a steel coathanger. No casting was harmed during the process.
Others might disagree and criticise, but it worked for me.

Not at all. The kettle descaler was almost certainly citric acid. This is perfect for the job and works much better with a hot solution.

Stephen