Can't Get Rid Of the Cooling System (Engine Block) Rust

[fusion.alive11]

I replaced all pipes (including the metal ones as they had mineral deposits in it) new radiator in place. But I can't get rid of the rust. Tried flushing the system several times, I have used Citric Acid solution once as well but that didnt work either. From the past few weeks I have been constantly flushing (after driving for periods of time) and refilling radiator with fresh water but despite draining all the water for at least 10 times in the past few weeks I cant seem to get rid of the rust. Its definitely better than before but go on a long drive and you could see rusty water everywhere in radiator and the expansion bottle. Been flushing like crazy but to no avail what to do this seriously is affecting my OCD nerve.

[farrukhzeeshan]

Which car it is?

Are you draining the block as well or just the radiator?

[fusion.alive11]

How does one drain the block? I usually remove the pipe below the radiator after driving the car for 30 to 60 minutes, it drains out all the water from the radiator and at least partially from engine block too.

Its a Suzuki Cultus EFI.

[KamranAslam]

The rust in the block lines you can't get rid of it until rebuilt.

[Xulfiqar]

You are not correctly flushing the engine,

After running the 10% citric acid solution for 20 minutes and draining the bottom of radiator and waiting for full cooldown, you need to disconnect a heater hose from the engine and use your garden hose pipe in there to shove all the acidic rusty water out.

Keep on flushing with hose for 10 minutes to push out all the crud and acid.

Whats happening with you is that the rusty acidic water is trapped inside and not getting removed.

Use the above to remove it.

Tip: make sure heater core also gets flushed.

[Xulfiqar]

It doesnt require a teardown and is quite easily flushed out.

[saad.ikram.5688]

Stop using water then if you dont want rust

[aziz.rehan]

Is it require to change the water body after using water in cooling system for a long time and then using coolant in it?

[KamranAslam]

It doesnt require a teardown and is quite easily flushed out.

These old Suzuki engines when used with water instead of collent for more then 2-3 months this develops bubble pockets of rusted dead-metal.

Now this flush part for the rusted surface lines is a piece of cake to ignore.

Eventually a big surgery is a way out.

[aziz.rehan]

Is this procedure correct?

[fusion.alive11]

Did exactly what you mentioned with citric acid flush but rust still is there.

[aziz.rehan]

From where to buy citric acid?The above video might help

[Xulfiqar]

Ive flushed such systems where the total capacity had reduced from 11 liters to 8 liters, Same citric acid 10% flush done for one hour then a good cooldown and flush out.

Literal rusty mud was pouring out of the drains and hosepipes.

[fusion.alive11]

This might work going bananas and leaving it for hours but citric acid can damage internal parts and might also cause leaks if left for long. I only kept the engine running for 20 minutes max probably then flushed all the citric acid out just like you mentioned. I also did clean water flush twice just after citric acid treatment to make sure no acid is left behind.

Anyways how does one flush Cultus Heater Core?

[Xulfiqar]

if your system is so badly corroded that citric acid will make it leak, then its a real bad case and needs to be fully repaired anyway.

Do not rely on a cooling system held together by rust, debris and scale corrosion.

the heater core is accessible from engine room via the heater pipes, if they are connected to engine, the citric acid will get to it and flush it out too.

[fusion.alive11]

Honestly I dont know how bad it is but bad enough that I still have rusty water even after so many plain water flushes. Guess going nuts with the citric acid is the only solution

[Xulfiqar]

do the flush again and follow the instructions properly.

I think you are not using a heater pipe to flush it out. There are two places that are usually below the outlet point of the engine lower radiator hose, those two places are the engine block and the heater core itself.

Meaning - you need to push that out with motive force - that motive force is the water from your garden hose. Without the motive that stagnant liquid wont move.

[fusion.alive11]

I did use garden hose to push out all the rust from engine block while I did citric acid flush. Infact I shoved the garden hose in the inlet pipe and left it running for 10 minutes or so after the acid flush. I will try the citric acid flush again. Heater in my car doesnt work I was told heater pipes are not connected, will take a look at them tomorrow.

[fusion.alive11]

From pansar, but be careful with citric acid, dont leave it for long. You might end up needing to change the pipes and water pump. But as brother xulfiqar said its a good thing you know your cooling system is about to fail in advance lol still dont go bananas with citric acid.

[FaatehRehman]

Were you using orange dyed coolant like Caltex before? That stuff is very hard to get rid off. It stayed in my car even after engine swap and coolant change.