Video attached. Rebuild was done about six months ago. This is the third batch of new coolant in that time. It should be coming out like new I think. Not brown. I can't tell if its particles. One time I left it out overnight and the brown had settled to the bottom, kinda like particles.

 

I have found that to be rust in the water jackets. Despite the best efforts of cleaning prior to engine assembly, this sometimes happens.
I've changed anti-freeze/coolant several times on a given build and I find that getting all of the liquid out via the block drain blocks helps.

As for your grammar and editing, I found that going into edit and then selecting advanced settings allows you to make changes in the title as well.
Being in the sun for hours...stay hydrated, wear sunscreen and a hat! Exactly the opposite of my best practices.

 

Well that makes me feel better. What do you think about inline coolant filters?

 

Best thing to do is an acid type coolant flush, followed by the "neutralizer".

For that matter, draining your coolant including from the block plugs, removing the thermostat, refilling it with water and a gallon of vinegar and running it for awhile, then draining that including the block plugs and refilling it with water and a pound of baking soda, then draining that including the block plugs, flushing it with water, and putting the thermostat and coolant back in (after letting the coolant stand and the much to settle), might do the trick. The old oxalic acid cleaners we used to use probably aren't legal in CA anymore.

 

I've never considered one because the thorough cleaning appears to eliminate the need.

 

air getting into the cooling system,including combustion gases getting into coolant will cause that-I had chronic trouble with rusty coolant until I found a crack in the exhaust crossover "Y"(in the water jacket,'624 heads ..) replaced the heads and coolant stays clear now-can see bottom of radiator tank through nice green coolant with a flashlight after over a year of use

 

This stuff has good reviews...

https://smile.amazon.com/Thermocure-...7625950&sr=8-1

 

Looks like I can get Oxalic acid on Amazon. How much would I use in place of the vinegar and how long do I let it stay in the engine?

This stuff looks to be highly regarded as well in this antique forum:

https://smile.amazon.com/Evapo-Rust-...s%2C223&sr=8-2

https://forums.aaca.org/topic/306350...e-oxalic-acid/

Another good forum:

https://www.jalopyjournal.com/forum/...#post-10619359

 

An old school radiator shop told me their secret.
Clean with Lestoil. As many times as necessary for the water to come out clean. Drive the car for a day or two for each flush.
Neutralize with baking soda.
Definitely remove the block drains during flushing.
For the final fill with coolant - USE DISTILLED WATER !!!!!

You are in California. I'll bet they have some type of Prop 65 regulation and special water you need to use in your cooling system because CA's regular water causes cancer.

 

The two drain plugs are on either side of the block in the middle just above the oil pan? Allen head plugs?

 

No disrespect, but distilled water is the worst choice for a cooling system. The BEST choice is de-ionized water. If you cannot get that, then regular tap-water is the lesser of two evils between that and distilled.

And yeah, literally EVERYTHING causes cancer in California. It's not called the "land of the fruits & nuts" for nothing...

 

Also, What's a preferred flushing technique? I read this and it's great but also really confusing. Nobody talks about engine block drain plugs but it makes a lot of sense getting that crap out right there.

 

The only way to properly flush is to remove the knock sensor ( pass side of equipped ) and the block plug on the drivers side. On more then 1 (old) engine,...... I've removed the plug and the crap in the block was so thick nothing came out till I used a small screwdriver to poke a hole in the crud,... then it all drained out.

If you don't pull the plugs out,..... your never really going to get the "heavy" crud out; it will just sit at the bottom of the block on each side.

 

I replaced the knock sensor as one of the first things I did when I got the car in 2017. I took the old one out and didn't know that it was a plug for the cooling passages. I routinely started to clean the gunk out before installing the new one and got a face full of coolant. Reminded me of numerous Three Stooges or Laurel and Hardy scenes, Lol,

 

This is not entirely true across the board. Distilled is fine if the coolant manufacture calls for distilled to be mixed.

 

 

I can't argue the chemistry, but all I can say is that I have been using distilled for decades, and my cooling systems look brand new 20 years later. For example, my 1995 GMC sierra full-size 4WD truck 305 TBI, I had an accident years ago and the body shop automatically was going to replace the radiator - until they looked inside. They couldn't believe that it was the original radiator. So they just had it flushed and re-used it.
Prestone actually did, for a very short time, sell de-ionized water. I bought a gallon and I still have the container to prove that it actually happened, because I have never seen it again.
From my experience, tap water leads to the coolant turning brown after a while: distilled stays bright green.

 

It's always been my understanding that de-ionized water is the most corrosive since it's been stripped of all it's ions. It can even leach chlorides from PVC -

https://www.finishing.com/147/97.shtml

I've always used distilled and have not had any issues either. FWIW

 

Ah, but you can.

Click "edit," the way you'd do it anytime you want to edit, as in the screenshot below:





Then click "go advanced," within the post's window, at the bottom, as in this screenshot:





That changes the window to this window, where you can still edit everything as normal, but including the title too, as in this screenshot:





Then "save changes," as you'd normally do it.

The block you used for your "new" engine build wasn't new, was it? If not, then how prepped and cleaned out was it? Where did it come from? And might it have sat empty for a long time before you revived it? Just wondering if it might've had a lot of rust and scale built up inside it before you rebuilt it? Probably not relevant, but thought I'd try to keep my post on topic LOL.

 

To LA's point, might even have come out of a boat with seawater cooling. The Merc 260 HP was basically a L98 with a boat carb intake on it; pretty sure Johnson/Evinrude, Crusader, Volvo/Penta, Indmar, etc. bought the same short block from GM and marinized it, as well. Even if the "sea" is freshwater, the block can get AMAZINGLY crudded up with rust, sand, mud, algae, ... in a word, FUNK.

 

Thanks for the thread title editing tips all!

 

I tried citric acid which is available everywhere. It seemed to work, but I think I may have added too much in. Took a while to flush it all out. Not entirely convinced it is a good idea to use it, but a year later all is still OK. Didnt think to neutralize, just pumped tons of garden hose water thru it and then drained, and did distilled water and coolant. then ran that for a while, and drained and replaced coolant/Dwater. Seems to be clearing up doing this. never messed around with the drain plugs on the block, if this experiment doesn't pan out, will try that next.


EDIT: Logged it over here https://www.thirdgen.org/forums/cool...ant-flush.html

 

There's a surprising amount of liquid behind those block plugs even with the lower rad hose removed.

 

Right: there's AT LEAST a half-gallon that will be left trapped in each side between the drain plugs and the WP, because the WP isn't at the lowest point of the water jacket. Can't "drain" something through a hole that's higher than the fluid. 1st law of plumbing, after all. Can't make it flow uphill.

 

I'm hoping the acid treatment is the key. I really have nothing else to try!

 

My car has done the same thing since I bought it due to PO not driving it but a few times a year for 10 yrs. Ive wanted to swap the engine since I bought it and now am about to is the reason I haven't chased a fix. My heater core took a dump and I didn't swap it because I didn't like the nasty water and hope to have new 5.7 in by Fall then I will swap heater core and radiator as I swap engine. Its good to find some remedys though I will remember what ive read here.

 

While we are still on the subject, here is a couple pics of that Prestone Purified Water that was sold many years ago.

 

Love the marketing to the target customer segment- NASCAR fans. "SCIENTIFICALLY" Purified Water. Lol.

 

If not done already, I'd suggest a throttle body bypass. I found alot of corrosion in those lines when I did that mod.

 

That's what I love about this board, not only new lessons in auto mechanics, but get some free plumbing lessons to boot !

 

when you do it, make sure to leave your radiator system open to free air until you are certain all the acid is out. otherwise pressure may build up and break something.

 

Mine was the block for sure. I had perpetually brown coolant till I swapped out the engine. Could never get the nasty out of it. I don't think it's possible honestly. With the way that 305 was - it was so nasty - when I pulled the knock sensor nothing came out. I had to jam a screwdriver through the rust. I flushed it at least a dozen times - it would be green with a swirl of brown and sludge would accumulate in the bottom of the overflow...... After swapping to the Vortec block (that was always ran with dex-cool - still had some in it when I got it), the system stays perfectly clean now. Overflow bottle is bright green and no sludge accumulates on the bottom.

GD

 

That sounds like my coolant

 

You mean like this?

I'm in the same boat as you, Tootie, but with a different car: My daily these days is an '07 Mercury Grand Marquis with a 5.4 swap.
The 5.4 came out of a 2000 F150 I used to have, and the coolant was always spotless - in that truck.

I rebuilt the engine and swapped it into the Grand Marquis, and now the coolant is always brown. I flushed it out I don't know how many times, and it's always brown by the next day. My son actually thought I was using Dex-Cool when he first saw it.
I've just learned to live with it (because it runs like a top, otherwise), but I've always thought about installing a coolant filter on the heater hoses to clean it up.

 

doing the oxy treatment right now, had some laying around from years ago. wow, some good crud coming up. looks like this may need a couple of passes. the longer the engine runs, the more crud appears in the radiator fill. working good. I added about 1 cup per gallon. eyeballed it. probably let it soak over night, drain tomorrow and repeat.

 

Have you removed the drain plugs during any of this?

 

yes, both the 9/16" plug on left side and the 7/8" knock sensor on right side. about 1 to 1.5 additional gallons drop out once you do this. its a huge mess. i don't look forward to doing it again, but will feel good about it when its all over.

Also took out the thermostat and backflushed while the block plugs were out by putting garden hose in thermostat housing tube. beside the wet mess, this is the biggest PIA of this job, for a TPI system anyway.

BTW - my coolant was staying green, but brown gunk would back up into the overflow reservoir. so its not as bad as it looks.

 

Lord! I am still working on this!! I let the oxy sit in my block for about a week, starting the engine a few times a day to warm it up and let it eat at cast iron corrosion. yesterday I decided it was time to pull the plug and flush it. after about 6 hours of fiddling, I'm still flushing the damn system! little, dissolvable chunks keep coming out. kept refilling with fresh water, running the car, draining, rinse and repeat. I was taking it off the lift, moving to driveway, putting back on lift. thinking this would be the last flush. finally I put the car on the lift for good, and starting refilling in the garage w/o moving off lift. made a huge mess! finally, it got so late, I just moved the damn car to the driveway and started flushing with drain holes open the whole time, while starting the car occasionally to get the water pump's help to move stuff around. did this for about an hour and went home. will be interesting to see what I find today. just the experience of one mans quest for green coolant!

 

In my experience it's pretty much a lost cause if you have significant corrosion build up. You can improve things, but you can't fix it without a tear down and a hot tank of the block. I have had two experiences with really nasty engine blocks - both were made better but never corrected the problem till I replaced the engine with a clean block that didn't have any corrosion in it. My Vortec block that had Dexcool in it's former life was bare iron everywhere. Not a spec of corrosion to be seen. And now I never see any brown sludge backed up into my overflow bottle.

GD

 

I'm about to find out! I can still see some surface rust in the block peeping thru the drain holes. maybe from sitting overnight. tempted to give it one last quick clean to remove surface rust, but I'm gonna go for it as it and see what happens. on the bright side of things, my garage floor is nice and clean, ready to rebuild my wifes car - front suspension tomorrow!

 

opened up the thermostat housing to put the thermostat back in and didn't like what I saw. so bought some Blue Devil Rad flush and doing this another round or 2. (its citrus based) from what I saw, it works pretty good. will keep you guys posted.

BTW - why the hell does the thermostat say RADENG on it, but appears to be backwards. RAD is on engine side, ENG is on radiator side. The spring does point down into the intake manifold right??

 

Same here.
Not that'll help the OP or the rest at this stage of the game, but a soak in the hot tub is part of the process for any fresh build I get involved with.

 

[QUOTE=Tootie Pang;6390016]Video attached. Rebuild was done about six months ago. This is the third batch of new coolant in that time. It should be coming out like new I think. Not brown. I can't tell if its particles. One time I left it out overnight and the brown had settled to the bottom, kinda like particles.



Where are the block plugs located?

 

Where are the block plugs located?

 

as mentioned in the thread, one is the Knock sensor in front of the starter on the passenger side, and the other one on the drivers side (mine is a hex bolt). I happen to be under my car already so I took a pic of each for you. A large catch pan is recommended as someone who has flushed their block from the t-stat housing it does work well.

 

What I like to do is pull the blug from the water pump and install one of those hose barbs, attach some heater hose, then attach that to one of those garden hose attachments and flus the bajeezus out of the motor.. .works excellent!


The truck TBI manifolds have an exit on the back of the intake manifold and you can attacch a hose there. Im not sure if the TBI f body manifolds have that though... but it really makes flushing the block really easy

 

I'm happy to report my coolant is staying green. I still have a bit of brown stuff surfacing into the reservoir from time to time, so I remove reservoir, dump and repeat. Not much at all. if I drain coolant, its green !! Went thru hell to get to this point. Don't even recall how many times I've flushed with just fresh water alone. After you do a chemical flush, flush with fresh water as long as you can stand it. Then add coolant and be prepared to do it again. if it is mild temps, you can mix your coolant at a pretty low %, so you're not wasting money on coolant, but dont forget that is what you did !

What ever you do, don't expect to be one and done. If that is your expectation, don't bother.

 

I think coolant prevents corrosion by forming a protective layer on the surface of the metal but it takes time to do this. Around 5K miles for Dexcool (if I remember right), and not nearly as long for American Conventional Green. The American Green has a short service life though, needs flushing much more often. I guess my point is a flush is only the first step in the process, The next step is to drive the car so the coolant forms the protective barrier that actually prevents the corrosion.

I chose American Green for my LS7 because I don't drive a lot and I break the seal on it fairly often. Needed something that forms the protective barrier as quickly as possible. I also chose it because it is formulated for older cars with brass radiators, which I have.

 

Thats good stuff Q. Did not know that. Hard to get 5K on an occasional weekend driver. Guess the idea is to stick with the American Green until you stop seeing any tidbits of brown, then switch to DexCool. Is DexCool what originally came in our cars from the factory?

 

Dexcool is the orange (or other colors) that GM began using after our cars. Don't mix it with your American Green, it used to be known to turn to jelly. If you drain coolant then it exposes the block to air and I think maybe you gotta build up the protective layer again. I wouldn't drain that block for any reason now.

Here's the article I found many years ago when I was trying to decide what to do with my engine swap. At that time I had an iron block, aluminum heads, brass radiator and heater core -- materials like a stock 3rd gen. You'll see why that's important to factor in when you read the article.

https://www.motor.com/magazine-summa...-or-orange-or/