[briansansone]

Im running a 4.3l vortec thats only 6 or 7 years old. I rebuilt the cooling system at the time; everything but the core.
At some point it developed rust problems.
First rad failed a few years in, second one failed about over a year ago
Everything on the system now is new again. Water pump, radiator, heater core, hoses, plastic valve, etc... within the last year.
When I replaced the last radiator, less than a year ago, I flushed the whole thing like nobodys business.
I draied it. Pulled out the thermostat, filled it up with flush and water, ran it , and drained it again.
Then I filled it with water, and drained after running for 20 minutes or so.
Then I routed the engine outlet hose out of the van, put a hose in the radiator, and watched it pump clear water through for like 30 minutes.
Then I put it back together minus the thermostst.
I added a petcock to the lower hose, in case I had to easily drain it again.
Then it was drained out again a few months later for some repairs. Filled back up with universal.

Today I checked it, and Im shocked.
Its just as bad as ever. Sludge and rust. And the coolor of the universal looks kinda like rust, but its rusty, sludgy orange.

What the hell am I missing. I keep the thing up, and its only got around 100K on it.

It has a disease that I have not been able to fix.
Please help!
Brian

 

[BogiesAnnex1]

What are you using for coolant, straight water is never any good especially tap water.

Once heavily rusted there is almost no answer short of disassembly and hot tanking but finding someone that hot tanks these days is mostly impossible.

Rust collects in thick deposits where ever coolant flow is slow or plugged within the cooling jackets, clear water running out is not an indicator that the system is clean.

Your short radiator life speaks to either not using a quality anti-freeze coolant at least not in sufficient amounts or going far too long between replacement or this is full of old Dexcool that has become acidic, or of course just water. Best answer for the average person is a 50/50 mix of old fashion green ethylene glycol base coolant mixed equally with either deionized or distilled water. O’Reilly’s house brand of green anti-freeze/coolant is plenty good for this with a drain and change every couple to three years.

The anti-rust agents in coolant are consumables they get used up doing their anti-rust trick this apples to all coolants, there is no such thing as a vehicle life long coolant except in some advertising executive‘s pea brain.

There are anode gadgets to be had that are sacrificial that can help control rust and preserve coolant quality, also, heavy equipment and truck shops have additive packages to restore and maintain anti-corrosive levels in glycol coolants that with use makes the base last as long as you keep up on the use of these additives. Coolant cost being what it is the big operators do this in place of periodic fluid replacement.

Bogie

 

[briansansone]

Thanks
I have not used straight water, except to do the super flush. So it only had water in it for the 30 minutes or so that I was running the hose through the engine.
I drained it, filled it with water, drained it, and then ran the hose. I did not want to pump coolant out on my driveway. I waited untill the water I drained was clean,
then I ran the engine with the hose feeding it. So I have never driven around running water in the engine.

I was afraid that I would find out its a chronic issue, .

The new engine ran green coolant all the way up until about a year ago. No dexcool ever.
I cheaped out on the radiators. I think that was part of the early failure.
The last time I put in a radiator, was when I really tried to flush the system. I figured a fush with a new rad may really help......or did I just clog it up?

Im shocked at the amount of rust. And i'm afraid its heading to early death.
An anode sounds cool, but seems unusual for a daily driving work van.

Do any of those rust flush products work? Dissolve rust? Or is it that once a passage is blocked...thats it?

I may try to run several cycles of flushing over the next week. Thats the expensive part. I can drain it once or twice at home, before I have way too much toxic coolant to deal with.
Thats the worst part.
You know I bet I could really clean up the system, if I had some way to deal with the coolant. That really limits you on how much you can play with it....before You have hazmat load of coolant.

Thank you for the input.

 

[36 sedan]

I would test for a combustion/coolant leak.

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[briansansone]

I would test for a combustion/coolant leak.

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Well I hope that isnt the problem. Its a well built, updated, relatively low mileage engine. It runs great. Everyday. But there is some cause of the rust issue.

 

[briansansone]

What are you using for coolant, straight water is never any good especially tap water.

Once heavily rusted there is almost no answer short of disassembly and hot tanking but finding someone that hot tanks these days is mostly impossible.

Rust collects in thick deposits where ever coolant flow is slow or plugged within the cooling jackets, clear water running out is not an indicator that the system is clean.

Your short radiator life speaks to either not using a quality anti-freeze coolant at least not in sufficient amounts or going far too long between replacement or this is full of old Dexcool that has become acidic, or of course just water. Best answer for the average person is a 50/50 mix of old fashion green ethylene glycol base coolant mixed equally with either deionized or distilled water. O’Reilly’s house brand of green anti-freeze/coolant is plenty good for this with a drain and change every couple to three years.

The anti-rust agents in coolant are consumables they get used up doing their anti-rust trick this apples to all coolants, there is no such thing as a vehicle life long coolant except in some advertising executive‘s pea brain.

There are anode gadgets to be had that are sacrificial that can help control rust and preserve coolant quality, also, heavy equipment and truck shops have additive packages to restore and maintain anti-corrosive levels in glycol coolants that with use makes the base last as long as you keep up on the use of these additives. Coolant cost being what it is the big operators do this in place of periodic fluid replacement.

Bogie

Is there also a possibily that when I was running the engine , without the therm, and a hose in the top side, that since the system wasnt closed, and pressurized properly, that the water did
not flow through everywhere it usually does, in a closed system?; leaving areas not flushed well? Like the path of least resistance, which is not the path the coolant normally travels?
Im just praying I can get it cleaned out before something overheats. I'd even replace the rad too, if I had to. There used to be places around here, in Atlanta, that would flush, test, restore radiators. Not anymore though.

 

[ExcellenceAuto]

Johnsongrass has a good formula for this. It involves about a gallon of vinegar.
At this point it might kill your freeze plugs. But that is your sacrificial anode, and they are probably paper thin by now anyways...

 

[36 sedan]

Also a good idea to check your motor and accessory grounds.

Electrolytic Corrosion in Radiators Demystified

www.mechanic.com.au

 

[Dogbreath077]

GM trucks have a chassis grounding issue. It will rear it's head in different ways, and this is one of them. Sometimes you go through a fuel pump a month, or a heater core every 6 months. Rather than test every ground, take a 10 ga wire and ground your frame, body, engine and battery. Also, if there is a clod of clay/mud/rust in a corner of the block, then it will take a lot to dissolve it out.(Flushing cleans the high velocity areas, but not the corners very well) I've used Ajax and Dawn liquid dish soap to get the worst mud out, and it takes a very strong solution, and multiple tries. When you say that you cheaped out on the radiator, did you mean that you bought a used one? Ouch. To see if you've clogged the new one, use an eBay borescope ($20 +/-) and hook it to a laptop or phone and peek inside. Your new radiator should be clean and green. Lastly, if the inside of the block is very rusty but has no mud, then it will be a few changes before the antifreeze stays green.

 

[BogiesAnnex1]

Unless it’s leaking compression mixture into the coolant resulting in it becoming acidic or the system is finding an air/oxygen source the most likely supply of corrosion materials is left overs that weren’t removed in the leaning process. This is common these days as most replacements for hot tanking are not very effective at this.

Grounding is a big headache these days since modern engines are using a lot of dissimilar metals so any electrical activity in the coolant makes the engine and it’s coolant connected equipments into a battery. Espeially the original SBC V8 and it's V6 derivative as many if not all the intake and head bolts are open to oily and wet places within the engine which requires sealant on these fasteners so that using fasteners as ground paths is no longer a dependable method of moving waste electricity from source to ground. I‘ve taken to grounding heads and intake independently of the usual block mounted ground strap. This doesn’t need to be a cable using a number 10 or 8 gauge wire well connected to each head and intake to the battery or chassis ground is sufficient.

Radiators and heater cores seem to do better when not grounded in this case as if you get stray currents out of the coolant since modern mounting of radiators and heater cores is to an insulator they are out of the current transfer business.

You can get litmus paper or dies to test your coolant for being chemically other than neutral. A high quality volt meter can be used to check for stray currents in the coolant itself.

As I said previously coolant need to be diluted with deionized or distilled water. Tap water carries enough dissolved chemicals, some like chlorine and fluorine are added by water districts and many other just come from the earth the water passes over and through.

Obviously if this thing is chewing up radiators and rusting the water jackets beyond a simple stain, something is way out of whack.

Bogie

 

[briansansone]

Johnsongrass has a good formula for this. It involves about a gallon of vinegar.
At this point it might kill your freeze plugs. But that is your sacrificial anode, and they are probably paper thin by now anyways...

Ahh, thats why the seem to erode first, and all fail at one. Happened on an old ford I had.

 

[briansansone]

Also a good idea to check your motor and accessory grounds.

Electrolytic Corrosion in Radiators Demystified

www.mechanic.com.au

GM trucks have a chassis grounding issue. It will rear it's head in different ways, and this is one of them. Sometimes you go through a fuel pump a month, or a heater core every 6 months. Rather than test every ground, take a 10 ga wire and ground your frame, body, engine and battery. Also, if there is a clod of clay/mud/rust in a corner of the block, then it will take a lot to dissolve it out.(Flushing cleans the high velocity areas, but not the corners very well) I've used Ajax and Dawn liquid dish soap to get the worst mud out, and it takes a very strong solution, and multiple tries. When you say that you cheaped out on the radiator, did you mean that you bought a used one? Ouch. To see if you've clogged the new one, use an eBay borescope ($20 +/-) and hook it to a laptop or phone and peek inside. Your new radiator should be clean and green. Lastly, if the inside of the block is very rusty but has no mud, then it will be a few changes before the antifreeze stays green.

I had never heard of the grounding problem. I will for sure ground everything. Additional grounds. It was a new radiator, just not an expensive one.
So I just started. I drained everything,then ran the hose through everything, but the heater core...my freaking jack broke as I was getting started. So I couldt reach the core..yet.
now im running a flush in it.
I plan to drain it again, then back flush the core, then more flush
Then thermocure
then quality coolant.

So are you saying that ajax and/or dawn work well? better than something from the store? Id love to use Dawn, and water, seeing how non toxic it is. That would be great.
I assumed flush was a mix of toxic who knows.
How much dawn/ajax ? My system holds 3.5 gallons
Thanks!

 

[briansansone]

Unless it’s leaking compression mixture into the coolant resulting in it becoming acidic or the system is finding an air/oxygen source the most likely supply of corrosion materials is left overs that weren’t removed in the leaning process. This is common these days as most replacements for hot tanking are not very effective at this.

Grounding is a big headache these days since modern engines are using a lot of dissimilar metals so any electrical activity in the coolant makes the engine and it’s coolant connected equipments into a battery. Espeially the original SBC V8 and it's V6 derivative as many if not all the intake and head bolts are open to oily and wet places within the engine which requires sealant on these fasteners so that using fasteners as ground paths is no longer a dependable method of moving waste electricity from source to ground. I‘ve taken to grounding heads and intake independently of the usual block mounted ground strap. This doesn’t need to be a cable using a number 10 or 8 gauge wire well connected to each head and intake to the battery or chassis ground is sufficient.

Radiators and heater cores seem to do better when not grounded in this case as if you get stray currents out of the coolant since modern mounting of radiators and heater cores is to an insulator they are out of the current transfer business.

You can get litmus paper or dies to test your coolant for being chemically other than neutral. A high quality volt meter can be used to check for stray currents in the coolant itself.

As I said previously coolant need to be diluted with deionized or distilled water. Tap water carries enough dissolved chemicals, some like chlorine and fluorine are added by water districts and many other just come from the earth the water passes over and through.

Obviously if this thing is chewing up radiators and rusting the water jackets beyond a simple stain, something is way out of whack.

Bogie

Thanks. I will try grounding the heads and intake. I did always think it was weird how certain bolts enter coolant passages, and must be sealed.
I wondered what the designers had in mind .

The system is somewhat open. Its the older vortec 4.3l. Its got the pressure cap , that leads to the reservoir, which has a hose that leads to outside air.
My newer 5.3 vortec is completely closed.

After the first flush, I think maybe its not as bad as I thought. Definitely rusted, but not as "muddy" as I first thought. Hopefully I am right, and its not beyond repair.
I'm going to pay attention to all the details, ground it better, and maybe seal off that hose that leads to the outside. If I can cure this one, i'll have a formula to keep my other rides nicely cooled.
Tap water is horrible for people as well.

It is surprising to me that there is not an easy solution. Like the rust eating spraypaint you spray on a frame. Rust eating additive? Seems like someonecould come up with a coolant that inhibits rust very well. At least for a while. Everything oxidizes eventually.
Thanks

 

[briansansone]

I am looking for an aluminum, or similar, T fitting that I can add onto my 99 5.3L one that has a cap, and gives me quick access to the system.
I have seen plastic ones, but I'd like a better more permanent part.
I envisioned doing a coolant change like you do a trans fluid change. An inlet port, and an outlet port. maybe even with a ball valve, to divert the flow.
Is that something that people do?
I will keep this truck forever. I want to keep it in top shape.