Silt in Toyota Land Cruiser cooling system

[RavenTai]

Anyone have any home tests to positively identify this stuff and tell us once and for all what this crap is?


For several years 93-97 Land cruiser owners have been finding a grey sludge in the cooling system, sometimes just a little sometimes a lot

Here is a pic of one extreme case:

there appears to be two parts to this stuff, a clay/silt like deposit usually gray but changes colors with the coolant used that moves in water like river silt, there is also a black fine sand like portion that settles out faster

We have been batting about different ideas as to what this stuff is for a few years now, ideas to date

Casting sand and clay left over from forming of the block and head
Solids that precipitate out from the inhibitors in the coolant
Results of electrolysis/corrosion/erosion/cavitation/ of the metals being deposited in the radiator
Head gasket, either the carbon fibre / graphite head gasket itself coming apart or condensed stuff in the coolant from combustion blowby.

Cold also be something else

In order to combat this stuff we really need to know what it is.

I recently got about a shot glass full of this stuff out of the bottom of my overflow bottle, I have it separated into three parts. A pile of very fine beige powder, a pile of mostly the black sand and a big pile of the two mixed together.

So far all I have been able to tell about it is that it looks like sand and clay, is non magnetic and does not burn melt or char when heated , it settles to the bottom in water, the black stuff much faster than the grey,

That means to me it is a non ferrous mineral or metal, not a hydrocarbon or organic compound,

This Toyota 1FZ-FE engine is a 4.5L inline 6 with an iron block and aluminum head, the radiator is aluminum in later years and brass in early years.


Anyone have any home tests to positively identify this stuff and tell us once and for all what this crap is?


I hear solids are expensive to send off to a lab, I am hoping to be able to figure it out at home.

More pictures

More discussion here:

http://forum.ih8mud.com/showthread.php?t=96871

[ June 21, 2006, 03:26 AM: Message edited by: RavenTai ]

 

[Ray H]

What kind of water are you guys using to dilute? Tap water? River water? Distilled water? Does this happen with the OEM antifreeze? (You are using antifreeze, aren't you?)

 

[RavenTai]

I bought my truck with a mix of the Toyota red and regular green, flushed it out with hose water then several fill and drains with distilled water, final fill was 50/50 Toyota long life coolant (red), distilled water and a bottle of water wetter. That was two years ago, at that time I found small amounts of the stuff collected in corners here and there,

a week ago I repeated the same procedure minus the Water Wetter, and found the stuff pictured above in the overflow bottle.

I do not know if this new stuff is just what broke free and collected (casting sand idea) or if it was created in the last two years. (precipitated)

so far I have not seen any pattern in when the sludge appears, some use distilled some use tap water, for the most part everybody uses either Toyota red or standard green antifreeze.

 

[Ray H]

I am mystified. The appearance of that sludge suggests a clay, but that's general "appearance", NOT "definitive".

 

[Buford T. Justice]

Sealer tablet remnants that have collected?

 

[carock]

The brown stuff is conventional rust sediment. Most engines will develop this over time, it gets worse as the car ages. The green stuff looks like a copper oxide, is there any brass/copper in the cooling system? I am surprised how much of this stuff you are getting, but it is not uncommon. A lot of BMW's develop this condition after about 80,000 miles. The solution is to install a coolant filter, preferrably a bypass filter across the heater core, or a full flow filter in series with the heater core. Your cars get this excessive sediment and oxidation from small leaks that allow air into the cooling system.The air creates bubbles and cavitation that greatly increase sediment and sludge in the cooling system. The air comes in through old hoses at the clamp, and other seals. The coolant flowing through the system "draws" the air in.Very difficult to trace and fix with all the hoses and joints in a modern car.

 

[RavenTai]

the stuff from the pictures above does have the color of iron oxide, it looks a lot like the local Georgia red clay witch gets is color from trace amounts of iron oxide,

but this stuff is non magnetic even when a very strong magnet is used, if this stuff had much Iron oxide in it then it would be magnetic, last flush when green coolant was present the small amounts I had found had a grey/green color, this time a beige cast when only red coolant was used,

I think the color could be from the red dye of the coolant, I did not make much effort to get the red coolant out of this stuff when I collected it, perhaps I should have

Here si how I got this stuff, After I pored off the coolant in the overflow I found this stuff, I stirred it up with a screwdriver than added about a quart of water and shook it all up and it came out looking like chocolate milk. I settled that in a mason jar overnight,

I drew off the top murky water with a turnkey baister and put it in plastic bags to settle for another day

That is what became the finest stuff

The bottom of the Mason jar got stirred again and settled for about 5 min in a plastic bag, the black sand stuff settled first,

The rest was pored off into a tray to dry, that became the beige pile (almost looks reddish brown) in the pictures

Here is some stuff that another member cought,

The lightest pile was found at the bottom of a 5 gallon bucket after flushing the heater core with a hose, the other two piles were captured in a coolant filter, separated using a similar method

The radiator on my 96 is aluminum, as is the one in this picture:

On earlier trucks (94 and earlier) there was a brass/copper radiator, 94 trucks also had a brass/copper heater core,

I am not sure if the heater core on the later trucks like mine is aluminum or copper. They redesigned the dash at the same time as the radiator change I do not know if the changes also meant a new heater core or not.

There is also a second rear heater core under the passenger seat, not sure of its material in any year.

 

[RavenTai]

quote:

---

Originally posted by carock:
Your cars get this excessive sediment and oxidation from small leaks that allow air into the cooling system.The air creates bubbles and cavitation that greatly increase sediment and sludge in the cooling system.

---

my understanding is that that that is a problem with Dexcool only. the lack of a fast acting corosion inhibitor allowed areas where protection was disturbed by cavatition or or a low coolnt level allowed corosion.

Toyota red contian phosphates and shoudl provide fast protection of iron.

is this not the case?

 

[Amkeer]

I only use distilled and toyota red and have never seen stuff like that.

Daily Drives:
-2003 Toyota Tacoma PreRunner,2.7 liter, 4 cylinder, Mobil1 5w30 ODO 29700
-1995 Toyota 4-Runner,3.0 liter,6 cylinder, Mobil1 5w40 tsuv ODO 17800
http://community.webshots.com/user/amkeer

 

[carock]

Once again, I will say what is in your radiator is from air leaks causing sludge in your coolant system. That blueish sludge is a gel that forms when this happens. The big rig trucks address this problem with coolant filters.BMW 745i's from the 1990's had this problem, as do lots of classic cars.Maye there is some coolant aditive that can fix it, but a solution is adding a filter.