Using evaporust in cooling system

[rundwark]

Does anyone have experience using evaporust or a similar chemical to clean rust from their cooling systems?

 

They claim that it's good for that here: http://www.evaporust.com/evaporustcsc.html

 

I've seen a ton of rust flushing my cooling system and am pretty sure my L16 was cooled with tap water at some point in the past. I'm about to swap on a rebuilt head (super excited), but before I do that job I'd love to get more rust out of the block. All hoses are good, the radiator and thermostat are new and good, and I don't have the heater installed right now, but the car still has occasional slight overheating issues.

 

Is it likely that rust is causing flow issues in the block, and if so, does it even make sense to use some rust removing agent, or should I just put a hose on it and flush it in the opposite direction of normal coolant flow?

 

Some pics from my previous head gasket replacement job, to give a sense of how rusty it is in there:

 

Current head:

 

Block:

[Stoffregen Motorsports]

I would be afraid that the chemicals might attack the metal in the head gasket.

[wayno]

I had an "R" block I got back from the machinist that had a lot of rust falling out of the holes when I got it back, I put it together, flushed the shit out of it, put some rust inhibitor in it, and then some antifreeze in it, then I drove it for years as a daily driver, I kept looking at the color of the fluid, and it always had that rust inhibitor/antifreeze color, it never changed.

[EastBay521]

i would cover up the water passages on the timing cover and pour clr in ther and let it sit for a day or 2 then flush it. or take the freeze plugs out and get in ther and break up the rust with a long screw driver and a pipe and blow every thing out like i did on my ka. my cylinder#4 was caked with rust

[DanielC]

If the engine is still running, do this to flush it out.

Remove the radiator. 

Remove the thermostat, put the cover back on the engine.

Put the upper and lower radiator hoses back on the engine.  Put the upper one on the thermostat cover to point above the radiator support.

There is a pipe plug, by number four cylinder, above the starter.  It is a block drain. remove it.

 

Get an air hose handy by the engine.  Take a garden hose, and shove it as far up the lower radiator hose as possible, and turn on the water.  Hold your finger over the block drain hole, by the starter.   Let the block fill with water, and when water is coming out of the top radiator hose, blow compressed air into the block drain hole.  The compressed air and water will agitate loose rust sediment, and you will see it come out of the top hose.  Let the block fill again, without air, and blow air into the drain hole again.  Repeat until mostly clean water comes out of the block.

 

You can do the same with the radiator.  You can also fill the radiator, shake it, turn it upside down, and spray water in to both openings to dislodge rust sediment.

 

If you do this before you use any chemicals to loosen the rust, you can still use them if you want, but the chemicals are being used on what remains in the engine, and not on what can be easily flushed out. 

 

You will need need to flush the chemicals out of the block after you are done, use the compressed air method again.

[DaBlist]

Here is something to consider by a company called Gano, they make different sizes to fit you upper hose to capture crud before it gets to your radiator. Google coolant filter and you will find others too

 

[DanielC]

I would not put anything in the upper radiator hose that would catch crud, plug up, and restrict or stop coolant flow.

there is a reason there is a bypass valve on most oil filters, and in the block, under the oil filter on Datsun L-engines

[DaBlist]

I would not put anything in the upper radiator hose that would catch crud, plug up, and restrict or stop coolant flow.

there is a reason there is a bypass valve on most oil filters, and in the block, under the oil filter on Datsun L-engines

It's clear so you can keep and eye on it. Easier to watch and flush than your radiator

[rundwark]

I would be afraid that the chemicals might attack the metal in the head gasket.

 

Me too, or even the head itself, that's why I'd want to do this before I swap it out.

[rundwark]

i would cover up the water passages on the timing cover and pour clr in ther and let it sit for a day or 2 then flush it. or take the freeze plugs out and get in ther and break up the rust with a long screw driver and a pipe and blow every thing out like i did on my ka. my cylinder#4 was caked with rust

 

 

Wow, it wouldn't surprise me if my block looked exactly like that…

 

If the engine is still running, do this to flush it out.

Remove the radiator. 

Remove the thermostat, put the cover back on the engine.

Put the upper and lower radiator hoses back on the engine.  Put the upper one on the thermostat cover to point above the radiator support.

There is a pipe plug, by number four cylinder, above the starter.  It is a block drain. remove it.

 

Get an air hose handy by the engine.  Take a garden hose, and shove it as far up the lower radiator hose as possible, and turn on the water.  Hold your finger over the block drain hole, by the starter.   Let the block fill with water, and when water is coming out of the top radiator hose, blow compressed air into the block drain hole.  The compressed air and water will agitate loose rust sediment, and you will see it come out of the top hose.  Let the block fill again, without air, and blow air into the drain hole again.  Repeat until mostly clean water comes out of the block.

 

You can do the same with the radiator.  You can also fill the radiator, shake it, turn it upside down, and spray water in to both openings to dislodge rust sediment.

 

If you do this before you use any chemicals to loosen the rust, you can still use them if you want, but the chemicals are being used on what remains in the engine, and not on what can be easily flushed out. 

 

You will need need to flush the chemicals out of the block after you are done, use the compressed air method again.

 

Awesome, thanks!

 

I think I'll try a combo of EastBay's and Daniel's instructions. I'm pretty sure I can get chip of quite some rust with a screwdriver, maybe I'll use my shopvac to vacuum it out instead of blowing it out so it doesn't go everywhere.

[Lockleaf]

Evaporust is essentially maple syrup combined with a catalyst and water. Go look up what maple syrup does to rust. It doesn't eat metals. It has a chemical reaction that converts iron oxide in to a stable inert chemical that can then be washed off. It isn't caustic or acidic, just good science. There is nothing in it to damage a head gasket. I hadn't ever thought of using it that way, but I wouldn't hesitate to use it that way.

[Buzzbomb]

I bet it would work. The only thing is you have to get the system filled to cover all the rust and that'd be what, $50 or $75? That being said, you CAN reuse Evaporust, so if you have something else to de-rust, it might actually be worth a try. It has the consistency of water, so I would first flush all the coolant out until it's clean, and THEN put in the Evaporust.That way you can reuse it with the least contamination possible. I will vouch for this product because it DOES work. The only hitch is you have to keep the part submerged in it, and this is certainly not a problem in a closed cooling system. I recently derusted a hood hinge for my Chevy that was rusted stiff, and it now works like new.

[DanielC]

Molasses mixed about 7 parts water, to one part molasses also slowly eats rust.