Grey stuff in rad opinion (1 Viewer)

[cruiserdan]

Dex cool ia a GM designed long life coolant.

Doug, interesting stuff there, very interesting. The block is, of course iron and not alloy. but that big old head is. As is the later radiator. I have thought for some time that the stuff was related to precipitates from the coolant. But I still think a visit to the chemist is in order.

The interesting thing about the grey matter that I have played with is it will go into suspension without too much effort. I have removed my overflow jar many times over the years. I have been able to rinse it out using a stream of water from the tap and then shaking up the jar. It can take some effort though.

It's a bit tough to do that with a block though :


D-

 

[landandsea]

Great info, Doug.

This thread brings to mind the idea of a coolant filter. It's been discussed a bit in the past. As I recall, someone was planning to install one.

Anyone have thoughts on the coolant filter idea?

Ed

 

[cruiserdan]

Somebody did do one a while back. Since the search works so well I can't find it It was mounted on the firewall on the RH side in front of the A/C bulkhead fittings.

 

[Beowulf]

For future reference...

-B-

 

[IdahoDoug]

Whups, yeah the block is of course good ol' iron. It's the head sourcing/creating the aluminum reactant. He feels the vast majority of the grey stuff is silicate drop out from the coolant, so the volume of it does NOT reflect loss of volume from the head or other aluminum parts. He also suggested we dip a digital multimeter into the coolant to get a stray voltage reading. Up to .5 volts is OK. He cautioned not to dip the entire thing into coolant as some multimeter sensors have solder in them and it will react with the coolant and dramatically change the reading. So just the tip. He also suggested comparing the reading with a cup of water as a baseline due to a comical situation where a guy's sensor was creating the voltage that caused him major grief (if the cup o' water causes a reading then your multimeter is the issue). Touch one end to a good ground, the other into the rad. Engine stopped check. Engine cold/rad open check. Compare.

Cdan - yeah, the stuff seems to be easy to break up and move, but nearly impossible to get that level of direct agitation to accomplish it at rad bottom and wherever it's settled in drifts inside the cooling system.

That picture above gives me the willies.......

Doug

 

[Beowulf]

Doug,
That advice on measuring voltage reminded me of a thread on 80sCool several years ago. One of the cooling system experts advised us that the rate of precipitation could be dependent on the voltage reading. Higher voltages = higher precipitation.
-B-

 

[Rich]

[quote author=Lars link=board=2;threadid=14475;start=msg136348#msg136348 date=1081579539]
...
3. Anyone have ideas/chemicals/products for a more aggressive flush of the cooling system?
...
[/quote]

Aluminum readily corrodes in the presence of water forming a layer of aluminum oxide which helps to retard further corrosion. Flowing water tends to remove the layer of aluminum oxide which exposes fresh aluminum to corrode. There are additives in coolant to protect and replenish the oxide layer to prevent your aluminum head from dissolving and being flushed down the drain when you replace your coolant. The available aggressive cooling system cleaning agents start with an acid flush followed by an alkaline neutralizer. The acid flush does an excellent job of removing the protective corrosion layer in the head. You would only want to do an acid flush if your block was truly and severely crudded up. I don't know if the acid flush would be effective in helping clean out the grey crud. The acid flushes originate from the days when blocks and heads were cast iron and radiators were brass and the objective was to remove rust and scale from the engine.

A high flow pressure flush of the radiator at a radiator shop so equipped will clean the grey crud from the radiator. I have seen it done. A home garden hose has sufficient flow to clean the grey crud from the heater cores if feed directly into the heater core outlet hoses (not tee’ed into the cooling system). A shop pressure flushing of the block may help. I expect that most of the grey crud collects in the heater cores and top of radiator. I had a lot in the top of my radiator and none in the bottom. The collection was noticeably concentrated on the passenger side.

 

[cruiserdan]

OK.

So where does the voltage originate and how would one address it if present? That would certainly offer an explanation as to why some vehicles have more than others. (Guess what I'm gonna do next )

 

[Rich]

[quote author=landandsea link=board=2;threadid=14475;start=msg136415#msg136415 date=1081610528]

Great info, Doug.

This thread brings to mind the idea of a coolant filter. It's been discussed a bit in the past. As I recall, someone was planning to install one.

Anyone have thoughts on the coolant filter idea?

Ed
[/quote]

https://forum.ih8mud.com/index.php?board=2;action=display;threadid=7062;start=0

 

[Rich]

[quote author=cruiserdan link=board=2;threadid=14475;start=msg136438#msg136438 date=1081613651]
...
So where does the voltage originate and how would one address it if present?
...
[/quote]

Stray current due to poor grounding of engine. I don't think this is the cause of the grey sludge. If excessive current were flowing through the radiator causing electrolysis you would see severe corrosion and pitting of the radiator.

 

[MoJ]

Comparing the voltage to a new car with Toy red in it would also be helpful.

 

[cruiserdan]

[quote author=Rich link=board=2;threadid=14475;start=msg136443#msg136443 date=1081614034]
https://forum.ih8mud.com/index.php?board=2;action=display;threadid=7062;start=0
[/quote]

Come clean Rich,

The only way you found it is 'cuz it's your truck NO WAY did search pull it

Oh, have you dumped it out yet to see if you are getting anything?

 

[Rich]

Here is recap of my experience:

I found grey sludge in the radiator top tank. No where near as bad as what is pictured in this thread but definitly enough to require corrective action. Flushed engine several times (more than an hour total using heater hose tee fitting, Prestone cleaner, drained block etc). Unable to remove sludge from radiator. Removed radiator, took to radiator shop, had all sludge power flushed from radiator. Radiator cleaned up well. Reinstalled. Several months later more sludge, just a little compared to before, in radiator.

I then installed coolant filter in preparation to remove (again) and flush or replace radiator. I didn't want to install a new radiator and have it get sludged (again).

As part of installing the coolant filter I flushed engine (again), this time without cleaner. Also, this time I hooked garden hose directly to each heater core outlet and flushed the heater cores one at a time, collecting the flush water in a bucket. Grey sludge was present in the flush waste water from the heater cores. After running with coolant filter for 1000 miles I cut open the filter and collected what I could from the paper element. It contained at most a teaspoon of crud. The larger portion was black gritty stuff as shows up in coolant overflow container. A smaller portion was a reddish powdered material which I presume to be a mixture of iron oxide and the grey sludge that we are so fond of.

I have done nothing to the radiator since installing the coolant filter. There is now less visible sludge in the radiator than when I installed the coolant filter. I have no way of knowing if more grey sludge is being produced or what I am seeing after the first radiator cleaning existed prior to cleaning the radiator and is just circulating around. For the most part, once it gets into the top of the radiator it seems quite happy to remain there.

 

[turbocruiser]

[quote author=cruiserdan link=board=2;threadid=14475;start=msg136438#msg136438 date=1081613651]
OK.

So where does the voltage originate and how would one address it if present? That would certainly offer an explanation as to why some vehicles have more than others. (Guess what I'm gonna do next )
[/quote]

Hi folks, I was away for awhile and saw this super thread. I am interested in following all the thought and theory out there on this subject. Also, I am indeed interested in the group purchase plan for laboratory analysis, is there an ante as such, if not maybe we should work out what the total would be, then see how many others may want to participate. Super cool thread!

Anyway, the voltage originates from two or three types of electrolytic reactions. I found something I felt I should share with you folks, it explains exceptionally well the ways this process occurs. Hope this helps.

Electrolysis occurs in our cooling systems in two or three ways. One of these ways is that stray electrical current from several operating systems in the vehicle flows to the cooling system. As the coolant flows to then throughout the system it develops a minor electrical charge (less than .3 volts). Once this stray electrical current finds its way into the system, it travels around (even through the hoses) looking for a ground. When the ground is located, the electrical current is discharged, no harm done. But, what happens when there is no ground to be found, or an ungrounded electrical device in the vehicle creates excess electrical current? The cooling system has the ability to hold large amounts of excess electrical current, which turns the coolant into an electrolyte. Any fluid that becomes electrically charged (like automotive coolant) becomes an electrolyte. If the excess current cannot be discharged by means of a ground, it continuously travels through the system, looking for a way out. During its travels, the charged coolant causes electrochemical reactions with the various surfaces it contacts. When it locates an extremely favorable material, it goes to work to try to consume the material completely. Think of the charged coolant as a very hungry termite. Trapped in a box made of several different kinds of wood, it travels around inside the box, looking for a way out. As it goes along, it samples the various woods. When it finds the tastiest piece, it sets about consuming that piece until it can escape. The charged coolant does much the same thing, traveling around in the cooling system, looking for that “tasty” piece. When it locates it, it “eats” its way through trying to escape. Once the material is gone and once the coolant can escape the electrolysis process is over. Until the next favorable material found.

Another way electrolysis occurs is the passage of an electric current through a conducting solution that is then decomposed in the process. When a cathode, or negative electrode, and an anode, a positive electrode, are dipped into a solution and a direct current source is connected to the electrodes, the positive ions migrate to the negative electrode and the negative ions migrate to the positive electrode. At the positive electrode each positive ion gains an electron and becomes neutral; at the negative electrode each negative ion gives up an electron and becomes neutral. The migration of ions through the electrolyte constitutes the electric current flowing from one electrode to the other. Electrolysis can cause material surfaces to pit and flake. The most common effect however, is corrosion. We have all seen the white and green solder blooms in cooling systems. We have also all seen sediments settling in areas of the cooling system. Ever wonder what caused them? Electrolysis is one prime candidate.

Aluminum affected by electrolysis will corrode rapidly in the form of flakes. These flakes will suspend in the cooling system and eventually build up causing system failure. Cast iron engine components will corrode, causing rust to enter the system, contaminating the coolant and allowing the system to slowly destroy itself. Soldered joints can become flowable and can produce leaks. Premature part failures, overheating, cavitation of cylinders and passages, and deposits causing system failure can be symptoms of or can be caused by electrolysis.

How can you test for and correct electrolysis? The test is very simple. Using a volt ohm meter (digital is preferred) connect the black or ground lead to the battery ground and lower the red or positive lead into the coolant in the radiator. Do not touch the filler neck sides or the tank. Any reading over .3 voltage is indicative of excess current entering the cooling system. Always perform this test twice, once with the engine off and all accessories off and once with the engine running and common accessories (radio, heater or A/C, lights ect.) on.

The first and most important step in the correction of electrolysis is a good visual inspection. Check all under hood wiring for loose connections or poor repairs. Look for additional accessories, poor wiring, or poor grounds. Hopefully the problem is just a poor ground in the engine compartment. This is usually the problem, as many DIYers and technicians alike fail to reinstall engine ground straps. If the problem does not readily present itself, prepare for what may be a long diagnostic process. Inspect the wiring under throughout the vehicle, paying close attention to the grounds. If no bad wiring is located, have an assistant hook up an ohm/volt meter, turn every-thing off and read the voltage. If it is in acceptable limits, turn on the accessories one at a time. When you see a voltage spike, you have your culprit. Locate and fix the problem, but continue with the test to make sure there are no other electrical problems. If you record unacceptable voltage readings with everything turned off, go to the fuse panel and remove and reinstall the accessory fuses one at a time. When you get a voltage drop, note which accessory you disabled and check the wiring for that accessory. After making necessary repairs, reinstall the fuse and check the system again. If there is no excess voltage present, the job is complete. If there is still excess voltage, continue removing and reinstalling fuses one at a time and make necessary repairs. If there is still excess voltage, the electrolytic process is likely coming from a reaction with dissimilar metals in the cooling system itself, particularly aluminum. In this case, constant, careful preventive maintenance is recommened and required to prevent harmful amounts of deposits.

 

[e9999]

made a beeline for the truck with my trusty voltmeter in tow...

first nothing on: got about 0.25V, but decreased rapidly down to the 0.1 range (losses through voltmeter? - it's a good one though)

than engine and some accessories on: most i got was 0.25V again but seemed to stabilize around 0.18V...

both kinda fluctuating values...

all below the 0.3V but not that much lower.... ???
E

 

[cruiserdan]

OK,

If I did it right (with my Bluepoint MT34) I got -108 milivolts with the engine off and the positive stuck in the radiator. I had -75 or so milivolts with the engine running.

Get this, If I put the negitive lead on the positive battery terminal I get battery voltage when I stick the other end in the coolant :-\
I guess thats right.

 

[e9999]

Dan, you got a bit less voltage that I did then. Maybe my coolant is older (PO, not bright red, more like red with a bit of brown tinge - maybe).
Well, since the coolant should be grounded, I would think you should indeed get the full voltage if you put the other elctrode on the battery pos. Normal.
Eric

 

[landtank]

I just checked mine. I recently tore the head off so all grounds are clean and good and 50/50 coolant with about 2500 miles on it.

Ignition on engine off -.051 vdc
Ignition on engine running -.033 vdc


if you have an auto ranging meter you might first set the range manually to the volt range so it won't jump around between scales and you get consistant values with others.

 

[cruiserdan]

Rick,

That would be 51 milivolts, right?

I see that the voltage dropped on yours as well with the engine running. My coolant is 4 months old and has about 3K miles on it.

 

[e9999]

all right, I'll change my coolant first thing and see what difference that makes.
will let yall know...
Eric