Freeze plug problems

[X66 714]

I noticed I had a coolant leak under my ss396 Camaro that I just had at MCACN in November. I didn't rebuild the engine because it only had 41k on the rebuild. I did change all the freeze plugs because I had one leaking. I used the green coolant 50/50 mix with tap water. I've probably only driven the car 3-400 miles since the restoration. I now have three freeze plugs leaking. The one pictured is one I just removed. These were brand new less than a year ago. The battery is never left connected when in the garage.

I sent this picture to my friend Larry (lbnaz) & he indicates that it's most likely a ground problem causing electrolysis. I guess I need to check my grounds but I wanted to ask if anybody has seen this & maybe, where was the problem found?
Thank you, Joe

[RPOLS3]

I always use distilled water when I mix with new green anti-freeze. Too much crud in the tap water here. Maybe the stuff in the tap water is reacting?

[X66 714]

It never has before but once I resolve the problem I'll change everything out. I will have the old stuff tested that I pulled out....thank, Joe

[William]

Possibly, the freeze plugs have become a sacrificial anode. Brass or stainless-steel plugs may solve the problem.

https://www.corrosionpedia.com/definition/1245/sacrificial-anode

[ban617]

Seems like all my engines have brass freeze plugs …

[X66 714]

Seems like all my engines have brass freeze plugs …

Normally that's what I do except I was going for as close to original as possible. Do you know how hard it is to find 1-3/4 steel freeze plugs without writing all over them? Not fun....Joe

[X66 714]

I just dropped off a coolant sample to Caterpillar. They will send it to a lab & I should get results back next week. 20 bucks (cheap) for lab work but I can't lose that engine. i'll keep checking for ground issues....Joe

[olredalert]

Seems like all my engines have brass freeze plugs …

----All my marine engines have brass freeze plugs, even if the boats are in fresh water. My incoming water is super purified (even de-ionized) before it goes anywhere in the house or garage, so no problem there!.....Bill S

[juliosz]

Possibly, the freeze plugs have become a sacrificial anode. Brass or stainless-steel plugs may solve the problem.

https://www.corrosionpedia.com/definition/1245/sacrificial-anode

What he said.

[ScottG]

Your coolant that is now in the engine will need to be fully flushed out , it is probably highly out of the PH range. Does your shifter cable seem to hard to move? If it is a bad ground it will try to use it as an alternative.

[David Billingsley]

One trick we always use is to paint the coolant side of the freeze plug with Permatex Gasket Sealer, the old tar like Permatex, to resist rusting out.

[X66 714]

I got the report back from Empire Caterpillar today. The said coolant was cloudy & Nitrate level was low. Also, here's some specs

BP (boil point) 104
FP (freeze point) -31
GL (glycol) 36
PH 8.6
CON (conductivity) 1103

I talked to the lab tech & they recommended flushing everything with clear distilled water or conditioned water which was mentioned here. He was recommending ELC coolant but said there was no reason the green shouldn't be fine. I will also use conditioned or distilled water. I'm also going back to see if my grounds are actually ground. Brass plugs this time. Quanta is out of paint so I'm on hold for that now...UGH. Always something

Any other thoughts? I'll start on it on Monday....thank you, Joe

[COPO]

The 8.6 PH level isn't bad. If below 7 that's when corrosion becomes a problem. Assuming the lab result temperatures shown for FP and BP are in celcius and those seem to be in the normal range.

[X66 714]

Here's the latest on coolant. We got some coolant test strips from the parts house & conducted some different test. they test Nitrite, PH, & FP. These verified what some had already mentioned. We did 3 tests with coolant that had been sitting in my truck for about 4 hours. Coolant was at 95 degrees

Test 1 was the coolant that I sent to Caterpillar. The results were vere close to what Cat said.

Test 2 was a 50/50 mix using new green antifreeze & water from the city. The results were barely better than what Cat tested

Test 3 was a 50/50 mix using new green antifreeze & deionized water from our system on the house. All results were substantially improved.

I guess I should've done one with distilled water. Maybe this week I'll do that....Joe

[1967 4K]

I’ve been reluctant to tell this but it has worked in my engine I had done in 2005. The engine builder told me before I run my engine to go to the auto parts and get one tube of the old time silver radiator stop leak stuff that’s been around for many years and put it in the radiator. He said it worked to help seal the freeze plugs and they would not give me any trouble.
His name is Sherman Gerlach, I always listened to him. I sure miss my friend.

[X66 714]

When I worked for Napa many years ago we sold lots of Alumaseal....Joe

[Too Many Projects]

I’ve been reluctant to tell this but it has worked in my engine I had done in 2005. The engine builder told me before I run my engine to go to the auto parts and get one tube of the old time silver radiator stop leak stuff that’s been around for many years and put it in the radiator. He said it worked to help seal the freeze plugs and they would not give me any trouble.
His name is Sherman Gerlach, I always listened to him. I sure miss my friend.


When I was more active with installing new engines, years ago, I would do this too, BUT, I always bypassed the heater core until the coolant ran clear of silver sparkles. I HATE replacing plugged heater cores.

[Hrdlx62]

Just an FYI, US Tool & Mfg. Co makes most core plugs in stainless. The ones I have used have no writing on them. They are out of Addison Ill.

[Hrdlx62]

Also, I have always used Permatex sleeve retainer 64040 or Loctite equivalent 620 for core plug installation.

[Mr70]

A good company,I drive by them almost every week.. https://www.ustoolandmfg.com/

[azcamaros]

According to the Assembly Manual, it appears GM added two pellets of their sealing compound to the radiator of all Camaros.

[COPO427]

When it’s time to drain everything, remember to remove both water bolts from the lower heads cause there’s a sh!t load of coolant in the block.

[X66 714]

When it’s time to drain everything, remember to remove both water bolts from the lower heads cause there’s a sh!t load of coolant in the block.

I got one of the 1/4" pipe plugs out on the starter side to drain the water from above the pan rail. Looks like I will need to remove some of the eng mount on the driver's side to pull that plug. It has the later design safety bracket in case of eng lift. that's in the way.

I checked all the ground to make sure they were actually grounds. I did notice where I painted the starter assm & then scraped some of the paint off where it bolts to the block, it did leave a slight step from the paint maybe not allowing it to sit flat against the block. I hit both surfaces with a Roloc just to make sure I had a good ground at that point....thanks, Joe

[83hurstguy]

Tap water is typically loaded with dissolved solids that will boost conductivity. As a result, you can create a galvanic corrosion cell within the cooling system.

The stainless freeze plugs referenced in here (US Tool) have been great for us. Stainless has a lot more strength and is stiffer than brass so they tend to stay in place better as well.

[X66 714]

I'm still getting alot of garbage when I drain the block so I have a question.

Could I do any damage by pulling the thermostat, blocking off the water pump inlet & heater hose connections & filling the block with clean evap-o-rust?

Thanks again, Joe

[83hurstguy]

I'm still getting alot of garbage when I drain the block so I have a question.

Could I do any damage by pulling the thermostat, blocking off the water pump inlet & heater hose connections & filling the block with clean evap-o-rust?

Thanks again, Joe

Evaporust actually makes a cooling system cleaner:
https://www.evapo-rust.com/thermocure/

Not sure the difference between thermocure and the regular Evaporust product, but I don't see the regular product causing an issue. Guessing the thermocure has some changes so it can be used as temporary engine coolant.

[John Brown]

Oxalic acid https://en.wikipedia.org/wiki/Oxalic_acid was the main ingredient in the old chemical flush that came in a two part can from your local auto parts store or dealership parts department, that came with a neutralizer in the lower half of the can.

Oxalic acid's main applications include cleaning or bleaching, especially for the removal of rust (iron complexing agent). Its utility in rust removal agents is due to its forming a stable, water-soluble salt with ferric iron, ferrioxalate ion.

[X66 714]

Since my last post I've been rinsing out the inside of the block. Rinsing is becoming cleaner each time. I've rinsed out the heater core & the radiator. Took the top & bottom hoses off & cleaned them. The spring in the lower hose was rusty but still usable. I took out the thermostat, blocked the heater hose connections on the engine & blocked the water pump where the bottom radiator hose goes. Tuesday about noon I filled the block with Evaporust. It's been sitting since. The positive side is I don't see anything dripping. Later today I will drain it off, strain it & possible return it to the block. I'll see what it looks like after draining.....Joe

[X66 714]

Drained & strained the evaporust & started rinsing the block....again. Decided to connect the radiator & heater core. Leaving the thermostat out & refilling the entire system with evaporust. Installed the starter & now running the engine until it reaches 160 degrees. The people at Evaporust says heat & fluid movement will help desolve the rust. I will continue doing this through the weekend & drain all the evaporust. I will then start flushing the system with clean conditioned water from the house. This is really bugging me. The car sat for 15 years. Maybe I should've just tore down the block for a complete cleaning.

On positive note, I fixed the tranmission leak....Joe

[X66 714]

Latest update. Did all the rinsing & drainng of everything. Evaporust foams up when run in the engine. Took alot of flushing. Mixed 50/50 deizonied water with green coolant. Ran it & tested the new mix at 100 degrees. -43, 1,200 plus on the nitrite, 7.5 on the ph. Took it for a 20 mile drive today. Did a retest at 160 degrees & got the same results. I bought coolant test strips & I'm going to test it every time I come back from a drive till I think the problem is gone. I did fix a trans leak as I indicated before. Also fixed an engine oil leak which was alot less fun. I had to pull the trans & reseal oil galley plugs....Joe

[napa68]

I did fix a trans leak as I indicated before. Also fixed an engine oil leak which was alot less fun. I had to pull the trans & reseal oil galley plugs....Joe

As much as I love this hobby, it can really suck sometimes. Stick with it. After all, these are just old Chevrolets. They shouldn't be that complicated :hmmm: