black mud in coolant.
 

I have been chasing a gremlin in a cooling system of another car I have, its an 03 camry on which I recently had to redo the threads in the block for the cylinder head. (they stripped out) - btw I bought the car with the bad condition and was towed back home.

after the rebuild, the car is running perfect except for one issue which is the cooling system.

during the rebuild I replaced the water pump as the old one was squeaking and was crusted up at the weep hole. Filled up zerex pink coolant. No air bubbles etc. Car runs for a month perfectly and I notice the coolant is a bit dark - a couple of weeks later the water pump fails catastrophically its literally shooting a stream of coolant from the weep hole - caught in time about 300 yards from my driveway.

pushed the car home, removed the water pump - got a replacement under warranty - same GMB pump and I removed all coolant - even pushing out the old coolant from the heater core, It was quite dark - there is something floating in it which does not settle immediately, but takes about 2 days to settle out. - Even a coffee filter does not fully clean it out and the "mud" that collects on the filter paper is like clay but black in colour.

a fresh fill of 1.5 gallons of zerex pink again with new water pump and cap - car is good for about 3 months and now today the water pump is weeping again - coolant is also black again with the same mud.

point to add - I drained about a pint of coolant from the radiator drain and it was clean as new - whatever this mud is, it kind of is on the top side of the radiator. - I cannot see any deposited on the metal of the radiator from the cap opening but the overflow tank has the mud, so much of it that it clogs the pipe nipple on it.

engine temperature is normal on the gauge - as they are buffered on toyota for about 15 degrees C, I checked it with a scan tool and see coolant temperature between 86-95C no matter how hot it is outside or if the A/C is off or on.

Anyone experienced this?

Going out on a limb here but offhand I'd say the engine was toast. I know the Camry's had a problem with the head bolts but the only region of the engine where the oil pressure exceeds the coolant pressure is internal. We're talking the block.

Water/coolant in the oil is usually head gasket but 95% of the time, oil in the coolant is a cracked block.

there is no oil in the coolant, its a clay like material, oil in coolant become blobs of gel - which I have none.

I have also seen cracked blocks mix oil in coolant but it always works the other way too because the hot coolant stays pressurized even with engine off - thats when it mixes with oil if the block is cracked.

I wonder if someone previous to you put a head sealer or crack sealer in. Either it did not set up properly or was not the common one under many names. .

I suspect some abrasive component of it might be taking out the water pump seals. The usual product is waterglass based. If so and set it should have been visable in the passages when you had the head off.

Normally would not be abrasive in nature either.. lt a glass like coating when set in my experience. Not blackish either. At the same time it is silica based I believe.

Maybe if it was me I would try some detergent based flushes. Basically use water and detergent. Drive a day and do it again. This process for several days.

At first I though a internally deteriorating radiator or heater hose. This would not destroy the water pump seal though. Nor would it have the consistancy of clay.

What is on my mind is what would prevent water glass from fusing? Unfused is what you may be describing. Or some crazy additive with it making it high tech and problematic. Just a wild guess by the way. I am sure of nothing.

good points.

I did clean every bit and corner of the cooling galleries in the block with long brushes and citric acid and cleaned out with water. flushed the radiator with a garden hose too (I think the radiator has that material trapped)

The old coolant that I removed was a gold/yellow colour (universal type I think) and the one I put in is the zerex pink for asian cars. I dont know if it has some extra ordinary cleaning properties.

another note I forgot is that both times the pump failed - there was a squeak from the belt when the engine was cold started. The pump leaked 3 or 4 days later.

Reading this reminds me of the black death sludge you get in water based house central heating systems - is the block or the head on this engine iron?

Try running it with straight water as the coolant and report back.

no sir - cylinder block and head both are aluminium - the radiator is aluminium too.

I have removed all coolant, removed thermostat and ran the engine with plain water, drained into a white bucket to see a very very small amount of the material settle at the bottom.

I see a very similar picture on google which shows it as "silicate dropout" - the engine did shoot hot exhaust into the coolant when the threads let go in the block - the coolant may have cooked it to the point of such mineral being precipitated out of it. - OR its just plain stupid stop leak giving me grief.


prepping for a citric acid flush now on the weekend and now looking for a better quality pump than the GMB brand, NPW Japan make good pumps, used them and also GMB on a lot of other toyotas/nissan/honda etc. - I have had good experience with NAPA rebuilt pumps too on other cars (mostly american) - but this one is a sure PITA - two pumps within 2000 miles is not good - doing the pump on this engine is not very hard but thats no reason for such work over and again.


Pump failures of this engine are littered all across the web, I think it partly maybe the routing of the belt too - the belt wraps around the pump this way

http://www.combibo.net/images/serpentineDiagram.jpg

that tensioner is a hard SOB to unload - in comparison the MB tensioner is a piece of cake.


If that flush dont work - Im going to remove the radiator and heater core and get a radiator shop to bubble them out.

This link suggests Ethylene Glycol eats aluminium =>

Antifreeze is antifreeze - not any more - Land Rover Zone

Some chemistry-like explanations in it too - could be right - could be "the internet"

found an answer to it

its burnt out stop leak. I had to remove the heater core too and took it to a place that used a water/air setup as a water hammer and purged out a lot of debris.

had to put in a new radiator as the stop leak had fused to the plastic of the radiator tank and was causing a slow erosion.

cleaned the whole system with shout/citric acid flush and got out lots of super fine gray sediment. hose flushed out everything again with hot connection from washing machine.

new japanese nissan branded pump, new radiator, new coolant (peak final charge truck coolant) - and its running again.

lesson learned - never underestimate the power of stop leak - it may stop a leak in the radiator but it may blow a hole in your wallet.

another learning was that aftermarket lower cost replacement water pumps for this engine are shipped with some sort of seal that is incompatible with even slight debris in the system, the replacements also warn to not use any silicated coolant. - Rubber seals maybe?


I have been recommended to install a coolant filter too and run it for a year or so to keep the system clean as there could be some debris still hiding somewhere. - I think its a good idea - the kit costs 70 dollars at napa

Glad you found the source. That's a real hassle and congrats to you for sticking it out to get to the bottom of the problem!

Rgds,
Chris W.
'95 E300D, 441K

Yep - traditional Bars Leak will do this. Makes coolant black. Gives one the impression they have oil in the coolant - lots of oil.

this was the culprit

http://i160.photobucket.com/albums/t...pss56gi9th.jpg


please refrain from adding stop leak to any system - no matter how strong the marketing or how convincing the sales person sounds.


this has damaged water pumps for me, choked up the expansion tank barb fitting and destroyed the radiator cap neck too.

Bugger...

europeon,and Jap cars and trucks,have tiny radiator passages.They Need to stop making Bar's,and Prestone.I had to replace a 126 radiator that turned to concrete.Alumiun seal is safe.

American cars have gone that way too. New chevys etc. But there are tons of people out there who will buy such products and continue to destroy their vehicles.

btw i rodded out this old radiator with a wiper blade spine, all the passages you see covered in the mud were fully clogged, along with a lot of others too - I think about half the radiator was clogged. and the total crap collected filled styrofoam cup.

good thing is that the radiator for this car is not pricey like a benz - an OEM repalcement is 70 dollars. - but its meant to be as its nowhere near a benz in driving.

update - the car is working great after the service - its been 7000 miles without problem.

Nice one