Grey stuff in rad opinion

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hmm.... wondering...

Mine is very likely pretty old given the color. Yours are basically new. Mine has higher voltage than yours...

Would be great if a simple measurement like that would tell us when to change the coolant to avoid deposits! Assuming that's even true, we'd have to figure out a good voltage criterion, though.

Oh well....

E
 
Excelent point Eric.

I certainly would suggest you check yours after you change your coolant. In addition there is a record on the board of Rick's and mine that can be compared to as our coolants age. Good thought, replace your coolant every 2 years or when the voltage approaches .3v or 300mv, whichever comes first.
 
just checked mine (work meter Fluke 87) engine off, it fluctuates between 70 and 18 Milli-Volts (0.018 to 0.070) spending most of the time around 30MV, Fresh Toyota red, water wetter and distilled water about a month ago. engine cool but run a 4 hours earlier, I would assume this battery action like many other chemical reactions would increase with temperature?

when I get home I will check with my meter, Fluke 73 series II IIRC, the work meter has alligator clip probes and the connections are a little beat up, good connections are more critical at this low level
 
If the sediment is effectively settling out in the top of the radiator, I suspect a settling tank would be more effective than a filter, without the accompanying flow restriction.

How hard is it to remove this radiator for a good cleaning with a garden hose every few years? The foam around the radiator on my wife's 80 is a mess, apparently someone had trouble putting it back in at some point.
 
Scott,

The foam craps out after a while on it's own. Removing the radiator is a fair job. It requires removal of the battery, battery tray, fan and clutch, shroud, grille, PS cooler hoses, radiator hoses, and it has delightful upper mounting bolts to get to :flipoff2: It is not something to do on a regular basis.


D-
 
This foam is way out of position, not so much deteriorated. I guess inverting the truck would be another option. What's a power flush, just a big water pump? The radiator should take a lot of pressure, a few adaptors and some hose clamps might get me an adequate flush.
 
[quote author=Scott M. link=board=2;threadid=14475;start=msg136761#msg136761 date=1081652858]
If the sediment is effectively settling out in the top of the radiator, I suspect a settling tank would be more effective than a filter, without the accompanying flow restriction.

How hard is it to remove this radiator for a good cleaning with a garden hose every few years? [/quote]

The filter is a bypass filter, it does not result in a restriction of coolant flow. In fact, it does the opposite. The filter plumbing reduces the overall restriction of coolant flow as it provide an additional path for coolant to exit the head and return to the pump.

A household water connection does not have enough flow to clean the sludge out of the radiator. I know that for a fact as I have tried. The radiator shop had a very large pump that pushed a massive amount of water through the radiator to flush it out.

Removing and flushing or replacing the radiator is a lot of work. Designing the coolant filter system, buying the parts necessary, making the mount, and installing the filter was a lot of work. None of this ranks very high on my list of fun things to do.
 
OK, so am I wrong in assuming that the water comes into the radiator at the bottom on the PS and comes from the top on the DS (US) ?
If so indeed, why do you think the stuff settles at the top rather than at the bottom? that seems odd.

I would also think that the best flush would go in the direction opposite to the coolant to push things out than further in.

the problem with the hose flush is that the rad flow cross section is very large compared to a hose, of course. But then I have 120 psi city pressure here, may give it a try...

interesting stuff

e
 
In at the top, out at the bottom.
 
I'd also think that the radiator has the slowest flow of any cooling system, so it becomes the settling tank of the system, eh?

DougM
 
I'll be danged! in at the top??? that pump is sucking the coolant out of the rad? Maybe to reduce the pressure in the rad...
shoot! would have been much better the other way around to push the crud out through the bottom...
so much for my intuition...
E
 
A lot of people are guessing. When I am guessing I say so. My guess is that the reason the sludge is predominant in the top of the radiator is because it initially forms in the cylinder head where temps are the hottest. I'll bet the sludge is soluble in the coolant at high temps under pressure and precipitates out when it cools in the radiator. I expect that the sludge is primarily consists of coolant additives. I would not be surprised if it is partially composed of aluminum, contributed by the cylinder head. I hope not. End of guessing.

It clogs the tops of the tubes. I haven't seen any in the bottom of the tubes. In order to flush it out of the tubes you need to have a pretty high rate of water flow. More than is going to come out of your faucet. If you blast with a sprayer through the radiator cap neck you can move the sludge directly exposed to the opening. You will not be able to clear the tubes that are not directly exposed if they are clogged with the grey sludge. The grey sludge is like a dense clay that does not dissolve in water. With enough force it can be removed. A large hose connected to a fire hydrant would be more than adequate for the job. :) A two inch hose connected to a swimming pool pump might also be up to the job. Not that running chlorine or muratic acid would be a good thing to do to an aluminum radiator.
 
I think the electrolysis bit is a wild goose chase. Open your radiator cap and look inside your radiator. Do you see a massive amount of pitting and corrosion of the the aluminum? Are you experiencing pinhole leaks in the heater and or radiator cores? No? Then I don't think the sludge is an electrolysis problem. Aluminum undergoing electrolytic attack gets nasty looking. It can happen. It can destroy radiators. I see no evidence of my radiator corroding.

By the way, I measured my coolant voltage about 9 months ago. You guys aren't keeping up ;)
 
Rich,

Don't just tell us you measured it, >:( What was it? ;)
 
yea, and then measure it again so we can see what is now after 9 months... :slap:
:D
E
 
Dan, I don't remember what the voltage was. All I remember was that .1 volt was the target value "not to be exceeded". What ever my voltage was, it was less than that, according to Mr Fluke.
 
Rich,

You seem to be discounting the electrolysis pretty firmly. Aren't there varying degrees of this problem? By this I mean that your comment that nobody's seeing pinholes, etc could simply mean that it's a low stray voltage type issue that's contributing to the precipitate process as opposed to a dramatic high voltage problem. But lack of pinholes and dramatic damage would still allow for the constant mild precipitate issue, right? I have no idea, so I'm asking the question.

Also, the mechanic told me of a guy who rebuilt his Vette engine with aluminum everything and had severe problems. He finally resorted to making an anode like you see on boats to control corrosion in salt water. He machined a mount that held a rod of zinc in the radiator opening and it worked great. The mechanic told me they used to actually sell radiator zinc sets in the old days but he hasn't seen them in years.

DougM
 
Doug,

Starting a bit less than a year ago I've been consuming all of the information I could find on the net concerning coolant problems with aluminum radiators. All references to electrolytic corrosion were focused on the rapid destruction of aluminum radiators and heater cores, and in the worse cases eventually aluminum heads. All of the reports were from firms involved in the replacement radiator business. It is a real world problem. I considered it a possibility when I first starting investigating my problem but discounted the likelihood when I could not find any evidence in my truck such as high stray voltage, obvious corrosion products, or obvious corrosion in the radiator.

Here's my list of guesses of possible causes:

1) Coolant left in too long results in additive drop out. Not consistent with Dan's experience.

2) Coolant left in too long results in heavy corrosion of head, which shows up in radiator. Contradicting information is that the sludge is such a uniformly fine material I have a hard time believing that it is primarily a corrosion product. Most corrosion products I have encountered in the past have been irregular and varying in physical size and shape.

3) Air in head causing hotspots that result in the formation of an aluminum phosphate type product. Air could be due to incomplete coolant fill or leaking head gasket. This guess has a basis in that it has occurred in the past. Contradictions to this theory are that aluminum phosphate is a white compound and tends to thinly plate radiator tubes in the coldest (center) areas as opposed to ending up piled up on top of the core. The reports I have found concerning aluminum phosphate also involved brass radiators. Maybe something similar is happening, but the appearance is different due to the different chemistry of Toyota coolant and or the aluminum radiator.

4) Hot gasses from head gasket leak sour the coolant and cause additive dropout.

Regardless of the contributing cause, I think it is most likely that the grey sludge is composed of something that came with the coolant, perhaps combined with what was once part of the head.

So, could electrolysis be part of the problem? I suppose it’s as good of a guess as any, it just doesn’t resonate with me.

I have found a firm that specializes in solving exactly this kind of problem, but I have not been able to collect enough sludge for analysis. Most of my sludge ended up being blasted out onto the radiator shop floor. At the time I thought my problem was solved. Were it ever so easy.
 
[quote author=Rich link=board=2;threadid=14475;start=msg136921#msg136921 date=1081668665]
Doug,

All references to electrolytic corrosion were focused on the rapid destruction of aluminum radiators and heater cores, and in the worse cases eventually aluminum heads. All of the reports were from firms involved in the replacement radiator business. It is a real world problem. I considered it a possibility when I first starting investigating my problem but discounted the likelihood when I could not find any evidence in my truck such as high stray voltage, obvious corrosion products, or obvious corrosion in the radiator.

[/quote]

I think this is a very valid point, but, just to argue another angle, with a thing like electrolysis, I think that when we read references that rapid crappings out of components was caused by electrolysis, what we are really reading is that someone had some super high power stereo or some super high power accessory connected without proper grounding. In these cases, electrolysis is easy to diagnose with definity because the test that tells the voltage in the cooling system is going to read ridiculous voltages. IOW, someone sees rapid radiator failure or heater core failure with swelling and screwed up solder and super high voltage and then that someone states that electolysis was the culprit. Well thats correct but that someone should specify that extreme electrolysis was the culprit.

IOW, the existence of any voltage indicates the presence of electrolysis. Period. What we are worrying about here is not extreme electrolysis (hopefully) but using the presence of voltage to help to determine the life left in the coolant. I would think of it as another analysis that will help you maintain your vehicle. It would be wonderfully interesting to graph out a voltage vs. time to failure chart to correlate the amount of voltage with the time to failure. I would imagine such charts exist for many different metals? If nothing else, marine zinc charts exist and would probably help at least understand the phenomenon. Anyway, if we are reading somewhere around .3volts, then that amount may mean that we are attacking more aggressively the metals, specificly the aluminum in the system, so, that may mean its time to change the coolant. A reading of around .3volts may also mean that the headgasket is having a hard time fighting the forces of electrolytic attack and that over time this will accelerate failure faster than a reading of around .006volts which is what I read on my coolant. Just thoughts, thought out loud.
 

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