Grey stuff in rad opinion (1 Viewer)

I was talking to a mechanic in town today who's quite well regarded by other mechanics in town. He's cutting up some metal for me to help out with a project to make a display for my company as he has a new plasma cutter and I mentioned I was impatiently waiting for a buddy to have time to use a hydrocarbon sniffer on my radiator. He asked why and I told him that there have been some head gasket issues and I've been finding these deposits when I change the coolant for years. Here's what he had to say (BTW, he owns his own shop and has been certified with Jaguar, Mercedes, Subaru and Ford during his career before opening the shop).

He says these grey deposits and the tiny grey/black flakes I see are chemical precipitates from iron and aluminum and mild electrolysis as well as the coolant itself. They are unrelated to any headgasket leak and indeed he says that he's never seen gases from a leaking head gasket cause anything to appear in coolant besides bubbles with one exception. That one exception he saw was a brownish sludge in a cooling system that was strong smelling of combustion.

Over the years, he's worked on a lot of cars and has seen this grey sludge on other models with the same frequency as he has on Toyotas. What happens is that owners typically do not change it out frequently enough and what I am seeing as a competent DIY'er is the flakes that WOULD have become sludge if left long enough. Even many shops do a poor job of changing out coolant - simply dropping the lower hose and refilling in a process that easily leaves 10% of the old fluid in there. As a result, the flakes are not properly rinsed out and get more and more accumulation as they change to sludge.

So, he thinks I'm wasting my time getting it sniffed if I have no symptoms of a HG and that my concern that these flakes were an indicator of a HG issue is unfounded. His feeling on HG issues is that the number one condition that correlates to them is owner neglect of the coolant system - even if it was long ago. Acids and corrosive substances work their way into the edges of the gasket, including crystalline formations that happen when the coolant dries that can microscopically separate the gasket from the sealing surfaces bit by bit. A bit of erosion of the metal sealing rings causes space for coolant, the coolant dries/boils from being too hot in the space (heat soak into the head after shutdown). Then another round of coolant incursion rewets it and the fluid now has a higher content of corrosive substances in there. And so on.

He feels the best defense against HG issues is merely clean and fresh coolant. He also felt the best coolant for the engine was not the latest generation of long life synthetic, organic, blah blah - but Toyota Red.

So, another data point on the topic.

Awesome re-cap. My radiator only has 20K miles on it, so I'll be sure to keep up on fresh red.

OK,

How do you explain this?

I an an original owner and my cooling system has been serviced at least every 24 months and has NEVER had ANTYTHING but Totota red coolant and ANYTHING other than distilled water, PERIOD. I have had to replace my radiatior recently and in the course of my radiator replacement I ran fresh water through the engine for over 30 minutes before I installed a BRAND NEW OEM RADIATOR. One week after I did this I had GREY s*** IN MY OVERFLOW TANK.

Where did that come from? My "neglected" cooling system?

D-

Based on my own personal observations, I don't expect that the black material commonly found in the overflow bottle is the same stuff as the grey sludge. I don't think the black material turns into grey sludge. The physical characteristics are quite different and, in my experience, appear in greatly disproportionate quantities.

In comparison to the grey sludge, I wouldn't worry about the black bits at all. I have only seen small quantities of the black stuff, in the coolant overflow bottle, and it does not appear to threaten to block the cooling system in any significant way.

The grey sludge definitely has the capability of clogging the radiator. If you're going to worry, worry about it. If you don't have visible grey sludge collecting on top of the radiator core visible through the radiator cap neck (drain coolant down to expose core) then you probably do not have any significant accumulation anywhere else in your system. The largest concentration appears to occur in the passenger side of the top radiator tank.

My guess, and this is only a guess, is that the sludge originates in the head under very high heat, and under the conditions it forms it is soluble in the coolant. When the coolant loses heat after leving the head the material precipitates out.

Not that this concerns me much any more but I'm still down with the "Bong Theory". The coolant is acting like a big water filter.

I did have another forum member look at my gasket. He was able to see another change in it other than the rear water jacket hole change. The ring seals for the cylinders have been increased in size making them stronger.

As for the hole change to round, I'm not convinced it is for better cooling as Robbie has repeated from a Toyota engineer, but any material will deal with stress cracks much better if holes are round. I think the change from a hole that follows the shape of the jacket to round is as simple as that, it will be less likely to crack and split.

I too think it has to something to do with mild electrolisis and all the disimilar metals, expecially with the aluminum radiator and OBDII (95-97). The toyota red is chucked full of orgainc salts that with the right reactions will fall out. I think dan was going to send out a sample that he has some day and then we can find out what the material are. I did a HG last month for a guy that had his guage reading high and tiny bubbles, I currently have one in the shop for coolant leaking under the gasket jsut about the whole length of the head on both sides, no other signs that the owner could tell when driving. 85k miles on the 94 cruiser. I will be doing this truck next week. I do 1-2 of this a month I do wish there was better options out there and the new gasket is better but of similare materials. Only time will tell. With my head gasket change over 3 years ago and 100k miles. I tore the engine down and no signs of any problems any where. So maybe it is right.
I do like the theory of the coolant creep under the gasket boiling out and then allowing more to creep creating more seperating of the gasket. Something very similar to Nature and the braking down of big mountains in to little rock with water getting into cracks and freezing weging apart big rocks and turnig them into little one. later robbie

Inline 6 with cast iron block and aluminum head is a recipe for eventual HG failure. The metals expand at different rates.

I know it's been discussed, but not sure if it's been done; do any of you have had the gray sludge analized by a lab to see what it is ?

Doug,

There is a picture of a radiator that was clogged with grey sludge. Robbie & Christo cut it open and it was full of the stuff at the bottom. I would be interested in getting your mechanic friend to look at that picture and to make a best guess on the source of the sludge. If the "material" is precipitate (meaning tiny bits of aluminum and tiny bits of cast iron) then that picture shows a LOT of material that came from somewhere inside the engine.

-B-

NO s*** -B-, looked to be about 2 lbs of the stuff.

I agree with Cruiserman......two diff types of metal expanding and contracting at the same time = trouble.....3fe does not have head gasket probs.....

[quote author=Tenncrusher link=board=2;threadid=14475;start=msg136012#msg136012 date=1081539430]
two diff types of metal expanding and contracting at the same time = trouble[/quote]

Granted there is different expansion rates involved but it doesn't mean trouble. It means that it must be taken into account during the design phase. Toyota isn't the only manufacturer that has had to redesign there head gaskets for this problem. GM had one hell of a time with there's, so much so aftermarket companies saw a chance at big money offering a better solution than OEM. Of course the demand was far greater than what we have :'(, but luckily Toyota did do something and we're not replacing the HG with the same animal.

From a common sense stand point it would be hard to believe the folks at Toyota did not take these factors into account. When I owned a 1988 22RE Toy PU in the early 90's I would often hear from mechanics that I was lucky to have the 4 cyl instead of the 6 because the mid to late 1980's 6 would suffer head gasket failure around 100-150k miles. I heard this often enough that I've always assumed it to be true. So you have a car company with a proven history of being the best in quality but they fail to learn from head gasket issues in the 1980's? Doesn't seem to add up.

Dan,

I can't explain that either except to say that your experience does not disprove what he feels is the source of the sludge/flakes - a stew of the dissimilar metals and ingredients in the coolant. My cooling system has been cared for since new like yours and yet I always get some of those flakes out that would have been sludge. Like you, I get a coating of grey in the overflow as well. As for neglect, I'll clarify that the HG issue is related - not the sludge/flakes.

I think I've offered this at least twice now - let's get a thread together wherein members offer to pay what they're comfortable with to have someone who has some sludge on hand send it to be analyzed. I'll personally call the oil analysis folks and ask who they'd recommend we send this sludge to. This would be highly valuable information because the sludge is doubtless playing a role in plugging even well maintained radiators, so many are in danger of this even if they're on the CDan/DougM anally retentive maintenance schedule. Any takers???

DougM

I'm in for $10.
John

I'd pitch in.

On a similar note, since I need to replace my radiator, I'll hack open the old one and take some pics of it's condition. Since I've only owned this 80 for 4 months, I know nothing about it's history... other than I replaced the head gasket. I did do a simple flush of the old radiator with the garden hose a few weeks ago and saw grey flakes... no visual sludge though.

I'm good

Excellent - thanks for the support. -B- also PM'd me and will pitch in and had a suggestion we get Christo/Robbie to provide a representative sample since they have a volume of these vehicles to sample from.

Picked up my stuff from the mechanic today and he had time to yak with me more about it. I also found out that he's worked in the cooling side of the business and was also a Toyota mechanic here at our local store (a very good operation). I asked him specifically what he thinks the stuff is. He said the silicates and another component of the additive package present in all coolants bind to the aluminum in a thin layer. As it gets thick enough (about half the thickness of paper - like my flakes), it is pulled loose, breaks into smaller/finer "dust" from the turbulence, and circulates until it settles. After a time, it accumulates into that thick paste like stuff. He took me into the back of the shop and picked up heads, coolant pipes and other parts and showed me it is in every engine to some degree.

Sensing the guy really knew his stuff, I asked what coolant he prefers. Tops for Toyotas is the red Toyota brand, in 2nd place is a product that's hard to find by Peak called their Global line. It's honey colored and is in a tan gallon jug. He says recently NAPA started carrying it but for years he's had to get it from a supplier. It's approved for Mercedes and a raft of other brands - more brands than any he knows of.

When I told him I had a DexCool type coolant in my truck, he asked what the radiator is made of. I told him it's copper with plastic top. He said he'd read reports that the DexCool stuff attacks solder in copper rads and GM only began using it after they'd switched 100% to aluminum radiators a while back. Whups. He said he wouldn't freak out and change it tomorrow, but he'd never put it in a copper radiator. He then showed me something that impressed me. In the back of his shop, he has the specific type of coolant for every single vehicle's manufacturer recommendation and strictly puts only the correct type in. There's one for older Chrysler, current Chrysler/Mercedes, Ford, etc and it was pretty impressive. They all have their own approved OEM fill and he keeps it on hand for all of them.

He also said there is documentation that DexCool attacks plastics and will make them brittle and crumble, specifically citing a recent GM engine who's head gasket has a nylon wrap around the sealing surface. They were failing at 80,000 miles and the DexCool was the culprit - actually causing the nylon to crumble into powder. GM fixed this issue and now ensures there are no plastic parts that can be damaged now coming into contact with the DexCool. For those of you who are still with me, the 80 has a plastic top on its rad and there have been some recent failures to consider.

Lessee, what else did we yak about? Oh - no surprise but he feels the "long life" coolants are malarky and would never let ANY coolant run beyond 2 years in his personal car. I asked him how the accumulated grey sludge could be removed and he didn't feel it could. At the Toyota dealership he was the only guy who removed overflow reservoirs as part of the cooling system service and he had some luck dislodging the stuff with a purple detergent who's name escapes me, but he felt it would be very difficult to get out of a cooling system once it had gotten into a thick deposit.

I told him of Cdan's experience and asked him how he could have gotten accumulation in his overflow so soon after a complete service and with an excellent history like that (100% toyota red, only distilled water, etc). He replied that it was simply that the inside of the aluminum block has a normal thin layer here and there and that it is constantly coming off in tiny flakes and small amounts. Cdan's fresh coolant had fresh additives that helped accelerate the removal process and these same additives better keep it in suspension and the slow flow in the reservoir makes a natural accumulation area. He didn't seem surprised by this.

Can't think of anything else at the moment...

DougM

[quote author=Tenncrusher link=board=2;threadid=14475;start=msg136012#msg136012 date=1081539430]
I agree with Cruiserman......two diff types of metal expanding and contracting at the same time = trouble.....3fe does not have head gasket probs.....
[/quote]

Hmm, then maybe it's not the HG because my 91 LC w/ 110k had the grey stuff!

[quote author=IdahoDoug link=board=2;threadid=14475;start=msg136296#msg136296 date=1081571103]

1. As it gets thick enough (about half the thickness of paper - like my flakes), it is pulled loose,

2. When I told him I had a DexCool type coolant

3. difficult to get out of a cooling system once it had gotten into a thick deposit.


[/quote]

1. My flakes were of the same thickness.

2. What is DexCool?

3. Anyone have ideas/chemicals/products for a more aggressive flush of the cooling system?