Flushing and coolant debris

[tmsmini]

Strange issue on a rebuilt engine...It appears this block did not get the full "cleaning" treatment on rebuild. I ran plain water at first and it soon become very dark with rust. I used Liquimoly for the first flush and then rinsed a few times, after running for 15 miles or so, the water/coolant was dark again. Thermocure was suggested. Again same thing. This time I collected the waste from the flushing as my wife as not happy with the rust stains on the driveway. I found the debris at the bottom of the bucket.

I have flushed three times with a chemical flush and rinsed at least five times between flushes and I am still getting debris and rust. The debris is mildly magnetic so I am assuming it is rusty debris.
I am ready to do another chemical flush, but I am not sure the results will be different. More pictures in the link


https://photos.app.goo.gl/27ikqv5eruRvZigw7

[94touring]

I will run a pretty strong solution of distilled water and phosphoric acid for a couple days of driving.  This is after initial flushes with a hose. The inno coolant is still completely brand new looking a couple years later.

[MiniDave]

That looks like sand to me, how the heck did that get in there?

I agree, you have to leave the solution in there for a while, not just in and out again.

[tmsmini]

Both flushes have phosphoric acid in them. At least one for sure as it is listed on the MSDS. The other MSDS says proprietary ingredients. The flushes are in for at least 5 days and one one was in for over 100 miles. It really looked like sand to me. At first I thought the phosphoric acid was just turning the rust particles dark. The debris is somewhat magnetic and I am not sure if the phosphoric acid changes the magnetic properties of the rust particles at all.
I will do another flush and see what happens.

[mascher]

The blocks and cylinder heads are cast in sand molds. It's common to find small pockets of sand in complex castings and they can remain for decades and be released apparently for no reason or when  cleaned in an aggressive way. I've pulled a shocking amount of sand out of 50 year old heads water jackets.

Kelley

[MiniDave]

Well now see, there you go!   

[tmsmini]

I wondered if sand casting was a probable cause. This Thermocure is pretty aggressive. I will let it work for a week and a hundred miles or so and then rinse it out. It takes a lot of rinses and temp/pressure runs to clear it.

[BruceK]

I have an apparent pinhole leak in my radiator that only appears sometimes by squirting coolant, which then gets blown up to the windshield in small droplets. This only happens sometimes when driving, maybe once every four or five trips. And unfortunately those droplets are looking more and more brown. So rust in the coolant. I might need to do a radiator but first thing I need to do is flush the system. It's been more years than I care to admit since I've done this. 

So I decided to pull the plug on the bottom of my 2-core radiator, and I also removed the thermostat so I could aggressively flush the radiator and also the block and heater core with a strong stream of water from a garden hose.  It didn't take too long before the flush came out clear.

I then flushed with a couple gallons of distilled water to get most of the tapwater out. Then I installed Thermocure to help deal with issue.  I've used this before on my JDM Toyota truck and it really seems to work well to deal with rust. It's not a typical aggressive flush, because it uses different chemistry to deal with rust. I plan to leave that in for four or five days to really let it circulate and I'll drive multiple trips with the car during that time.

I fully expect the Thermocure stuff to turn very black in response to the rust and require a lot of flushing to get back to clear water. Then my plan is to go old school with good old green antifreeze/coolant. Apparently a lot of the modern coolants are not good for an old-fashionedcopper/brass radiator like the one fitted to my Mini.

Then I'll have to make a decision about buying a new radiator or taking this radiator to a radiator shop to see if they can find and fix the intermittent pinhole leak.

More to come.

[MiniDave]

I have an intermittent coolant leak on my green Mini too, I have yet to figure out where the heck it's coming from and why. It will be fine for months at a time, if I pull the radiator cap the coolant is right where it's supposed to be. The next time I check it the core is exposed, but it doesn't take more than a pint or so to bring it back up.

I have a cardboard under my parking spot and I have seen telltale green spots on it, but I can't find anything wet on the motor. I would have suspected the head gasket except for the green on the cardboard. It never runs hot, unless I let it get too low on coolant.

I'm amazed at how much "mud" the heater cores can hold, and it takes a lot a flushing to get it all out! I'll bet if you were to flush it again you'd get more brown mud out now.....

I'm not familiar with "Thermocure", I'll have to look into it.

[BruceK]

Dave, Thermocure is a cooling system version of the Evapo-Rust rust eliminator product. You may have seen the Edd China YouTube video where he submerged an entire very rusty Land Rover chassis in a huge vat of the stuff and it completely removed all the rust leaving it looking almost new. It's got some crazy chemistry involved that is non-toxic and non-acidic, and works fantastically. There are tons of YouTube videos of people who've used the Thermocure coolant version with incredible results. It's not cheap, but it is very effective. 

Before I used Thermocure the first time on my old Toyota I poured an ounce or so into a full water bottle and dropped a rusty bolt in there. Within a day the rust disappeared completely and the bolt looked new, but not shiny. Quite a result.

[MiniDave]

I've used Evaporust for years, I'm familiar with it.....just hadn't heard of Thermocure

[BruceK]

I drained the Thermocure this morning and it was black, black, black, as expected, and smelly too. I flushed the engine and heater core with a garden hose for about 15 minutes, and then I flushed everything with about 3 gallons of distilled water to displace the tap water. I plan to pull the radiator out tomorrow morning (it's way too hot now) and take it to a local radiator shop for evaluation. I've been Googling to find a shop.

One place's website says this:

"Whether you are a do it yourself-er, or a fleet manager that oversees a large fleet of cars or trucks, we have what you need to get your vehicle back on the road.

Our extensive inventory covers applications as small as the Volkswagen Beetle all the way up to a Peterbuilt 379 and even Caterpillar Gen Sets like the popular 3512 used in may oil field applications."


Ummm. What? Do you think they meant the New Beetle?  I mean surely they'd know...

[MPlayle]

Whomever wrote their webpage may be too young to know about the old Beetles being air cooled.

Especially since the New Beetle (water cooled) was first introduced in 1997 (now 28 years ago).

[tmsmini]

Ummm. What? Do you think they meant the New Beetle?  I mean surely they'd know...

Maybe the vertical oil cooler? Cheaper to replace even 50 years ago...

[94touring]

Whenever I put a coolant system together or have to drain a system, I use 50/50, but also dump in about a 1/16th of a gallon of phosphoric acid.  It always keeps my coolant bright green indefinitely.  The leaks you guys see might be from running hotter once in awhile and it being pushed out the vent of the cap.

[BruceK]

So ... I think I mighta found the source of my intermittent pinhole leak. Either a gremlin has been in there with a file, or my radiator has had a disagreement with the inner wing.

[BruceK]

Actually I was aware of prior contact they made, but I thought I took care of that about 8 years ago when I relieved a good portion of part of shut line channel of the wing. They shouldn't have made contact after I did that. But ... I might have reinstalled this 2-core copper radiator without thinking about possible damage it had after a disaster with a chineseium aluminum radiator that got destroyed by being too close to a fan. I put this radiator in and it seemed be okay. Until the pinhole leaks started years later.

Anyway, I'll take it to a radiator shop next week and see if they can repair it or if I'll need to get a new one. 

[MiniDave]

Wow, I'm surprised you had to remove that much of the channel to get clearance.

[BruceK]

Wow, I'm surprised you had to remove that much of the channel to get clearance.

Me too.  I did that about 10 years ago and haven't thought about it since. 

I was talking about it with Michael today at a car show and we noticed that the radiator shroud on his Mini is thinner than the one on my car - meaning on my car it pushes the radiator a little further out from the engine. The other thing is the wing on my Mini has been replaced (before I got the car) and I think they moved the inner wing in toward the radiator a little bit when they were welding the new wing on, resulting in a wider channel there.

I use the bigger metal bladed tropical fan so extra clearance between the fan and the radiator is a good thing.