My coolant is brown after my rebuild which means I've got rust in there. Got a lot of good info on my other thread about this. Now I need to do the treatment and flush.

I have been told to absolutely drain from the block drains and the knock sensor.

For the flush here is what I plan to do. I would love opinions as I just want to get rid of the rust issue. FWIW, I always use AC Delco green coolant from the dealer.

PROCEDURE

1. Get the car up in the air a bit.
2. Remove Thermostat and upper hose
3. Drain System
   1. Disconnect lower radiator hose
   2. Open drain on radiator
   3. Remove both block drains on block and the knock sensor
4. Garden Hose Water Flush
   1. Flush into the thermostat housing on the intake manifold until the block drain plugs come out clear
   2. Flush into the upper radiator hose inlet and through the radiator until clear
   3. Let system drain
5. Acid treatment
   1. Install all drain plugs, hoses, but not the thermostat
   2. Fill with Oxalic Acid and tap water mixture (1 lb powdered Oxalic Acid to 3 gallons water)
   3. Run engine up to normal temperature and shut off
   4. Let sit for an hour restart for five minutes/rev it a bit and shut off again, repeat every hour for four hours
6. Drain/flush neutralize acid treatments
   1. Repeat Steps 2, 3, and 4.
   2. Repeat Step 5 but instead of Oxalic Acid, use Baking Soda, and only perform for five minutes
7. Drain and Flush
   1. Repeat Steps 2, 3, and 4.
8. Close up and refill with distilled water and new coolant

 

Re. the block drains:

The pass side drain IS the knock sensor. See, in 1955, those genie-asses at GM were already thinking ahead toward EFI; they KNEW it would be possible someday, and they KNEW GM wouldn't bother developing a new engine for AT LEAST that long because they'd get their butt kicked so bad by the Germans and the Japanese in the 70s when their quality went to total excrement. So they prepared in advance: they designed in a port for the knock sensor, but they cleverly disguised it as a coolant drain, so the dweebs over at Frod and Xler wouldn't get the remotest dimmest haziest foggiest slightest hint of a whiff of a glimpse of a scent of a CLUE what they were up to.

A pound of oxalic acid sounds like a bit much; I seem to recall when we bought it as part of a "kit" it came in a can just a shade bigger than a 12-oz beer; butt hay, it's been A LONG time. Don't want to admit how long, but it's fair to say, it's a SIGNIFICANT part of a century. The instructions that came on the can said something like (at your step 5.2), pour it in, then run for 15 minutes at 1500 RPM, then sit for a half hour or if REALLY contaminated overnight, then start up and run for 15 minutes at 1500 RPM again, then drain etc. You can leave the baking soda in for more than 5 minutes, it doesn't really hurt anything, but the engine needs to come up to operating temp and THOROUGHLY circulate it.

In CA you have the problem of what to do with abuncha severely messed up oxalic acid solution that comes out of the motor. Back in the day everybody thought it was OK to just let it run down the storm drains, but I doubt that would be considered kosher in CA in 2020. Find out how many years of crushing rocks in a [michael bolton]federal pound-me-in-the-a$$ prison[/michael bolton] you would face if you got caught, before doing such a thing.

Deionized water would be great but it's a bit $$ comparatively and the benefits are minimal in the automotive environment. After all we're not washing circuit boards for medical or aerospace applications. The main thing is, avoid putting abuncha lime, chlorine, and whatever all else is in tap water, into the engine.

*splits sides with laughter*

Green coolant is green coolant. It's a COMMODITY; ethylene glycol. The green dye is added so you won't accidentally be tempted to put it in wine, like cheeeeep wine makers do (it covers up a bit of bitterness and acidity in the rotgut). There is NO SENSE WHATSOEVER in buying it from the stealership. I'm reminded of a tower crew that used to work for me sometimes, that needed dielectric grease to put in broadcast antennas and transmission lines and such... they swore that the ONLY WAY they could get the right stuff was to order it from RCA. (remember that name? https://worldradiohistory.com/Archiv...talogs_RCA.htm) It was $36 a tube at the time (musta been mid 80s). I told em, go to the Dow-Corning distributor, order part number 4, it's $5 a tube. (seriously, the D-C part # is ... 4 ) They didn't believe me. So they tried it: ordered it from RCA, and while they waited, went to the D-C distributor (I had worked there at one time, told em where it was and what to ask for) and bought that. When the RCA stuff came in they opened up the RCA box, and inside was a Dielectric https://www.dielectric.com/antennas/ box (antenna mfr), and inside that was ... you guessed it ... a tube of 4. [george wilbur in my cousin vinny]IIII... DENTical.[/george wilbur] Don't do the same thing with coolant.

 

Ok, that is music to my ears about the green coolant. That AC Delco stuff is only sold at a few dealers. I thought that OEM coolants had special lubricants for the other factory equipment. Stuff that Prestone, Peak, etc don't have. But if it's all the same, then dang, I'm all in.

As far as the 1 pound, they may have meant 16 fluid oz (powder) when they said 16 oz for up to 3 gallons I which case that would be 1:8 to 1:24 acid powder to water by volume.

 

 

One of the best movies of all time.

 

It would probably be worthwhile to mention:

Heater cores (OE ones anyway) were brass & copper, soldered together. Over time, the solder can erode; that's usually how they ultimately leak. Strong acid will DRASTICALLY accelerate the process. Might be a good idea to take the heater lines loose from the block before putting in the acid, and capping the nipples on the intake, WP, rad, or wherever. If you have the OE oil warmer, the same thing may apply, I'm not sure. You can flush both of those things with the garden hose; force the water through them in reverse of the normal way. For the heater, the smaller line is normally the "supply" and the larger the "return", so stick your hose up the larger hole. (what lovely imagery that instruction conjures) You can run the baking soda through them though, it will help clean any rust buildup out of them, just like using the BS on batt terminals & connectors to clean rust off the hardware there.

Another point is, green antifreeze has some additives to help resist corrosion, which are consumed over time in the process of doing their job. There are acoupla brands of "additive & WP lube" you can buy, that restore these chemicals (silcates mostly) and are even useful with new antifreeze, to coat freshly etched metal with a fresh corrosion-resistant coating. Kind of like Parkerizing your firearms parts. It'd be a good idea to fortify your coolant with that after etching all the metal bare & clean with the acid.

And, Peak comes out of the bottle blue, but turns greenish in a short time. It's not quite the pretty bright green of Prestone though. It's perfectly good, is exactly the same chemical composition and every bit as "quality" as Prestone, just doesn't look as good.

There's another additive you can use that helps the water to make more intimate contact with the metal at the molecular level. Water Wetter is the brand name. Not sure what it is but I think it might be just a non-foaming detergent, kinda like the stuff you use in a carpet cleaner, that cleans without leaving suds. It can make a significant improvement in overall cooling system efficiency.

 

Great info and conjured visual. I will disconnect the throttle body (its new) and heater.

I am really hoping this does it. My car overheated AGAIN.
100 degrees outside, air conditioning on, city driving.
Newly rebuilt L98, water pump, big radiator, big radiator fans, hoses, thermostat, careful air handling, functioning hood vents, etc, etc, etc.

But browning coolant. I am cautiously optimistic. I've read plenty by now that these acid cleanings can make a huge difference in how cool an engine runs. I really have nothing else to do other than question the laws of thermodynamics. That's all.

These cars ran great when they were new, never overheated in any conditions. It has so far escaped me as to how to get it back to that level of cooling durability. Although I can't imagine how a thin layer of rust can mess things up so bad, yet I seem to have nothing else to try.

 

Tomorrow it's going down...

 

Well I did it yesterday. Went slow and baby-sat it throughout the day. First block drain flush removed a lot of rusty, dark flakes. Both drains were blocked but after poking it all came out. Used 2 lbs of oxalic acid for a 3 gallon cooling system. Removed thermostat, bypassed heater core/TB. Kept temperature at running temp for about 4 hours. Ran the engine every 20-30 mins to circulate. Drained- a humid, stinky mixture coming out (captured most of it but still messy- wife is going to kill me unless I get the rust-colored stains off the concrete before she sees them). Garden hose flush through all inlet/outlet-ways - thermostat, radiator inlet, radiator cap side, block drains, water pump inlet, radiator drain. Filled with water, ran for 5 minutes. Decided not to use neutralizer. Drained, flushed again, fully drained filled with new green coolant. Flushed heater core/TB loop. I think I have become a pro at the cooling system on these cars.

I could see the rust coating the water jacket on the cylinder walls through the driver's side drain opening. Afterwords it looks like new iron in there.

I have not tested the car yet on the road.

Video clip of one of the garden hose flushings! Thanks for all the help. Will report back on improvement.

 

wife is going to kill me unless I get the rust-colored stains off the concrete before she sees them

Cover the stains up with a nice long John force style burnout!

 

Sure, that way my children will never find my body.

 

Try some muriatic acid to clean the driveway

 

Thanks. I read vinegar and 30 minutes with light scrub does the trick.