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Coolant turned to sludge, replaced complete system, HAPPENED AGAIN!

H

hjz8785

New member
Alright, I'll try to be as precise and to the point as possible. About 6 months ago after shutting of my 06 3.8L SC, I noticed a bubbling sound coming from the reservoir. When I opened it there was sludgy dark red fluid in it...NOT GOOD! At first I thought it was infamous head gasket/intake gasket issue...it wasn't. Upon further inspection and my mechanic and I brainstorming, we figured it to be the transmission cooler on the inside of the radiator had cracked and leaked into the coolant causing the problem. SO, we replaced EVERYTHING on the cooling system except the heater core. This includes: radiator, tranny cooler, water pump, plastic elbows, EVERY HOSE, and the thermostat. Replaced dexcool with the yellow stuff. ALSO, we changed the tranny filter and fluid. We flushed the entire cooling system with chemicals and filled it back up. Car ran AWESOME for 3 months, ran at great temperatures in this Arizona heat. Checked the coolant several times the first month...no loss of fluid, no discoloration. A week ago I noticed some slippage between 2nd and 3rd gear. Fluid level seemed fine, so I bought BG Transmission fluid conditioner. Checked the coolant at the same time and noticed it was low...then I noticed the sludgy film around the inside of the radiator cap...NOT AGAIN! :mad: Added some water and drove it home...shifted much better may I add. Got home and further inspected the coolant, doesn't look sludgy, still yellow and clear. WHAT IS CAUSING THIS?! All and any help will be GREATLY appreciated. Thanks guys!
 


I can imagine the type of damage that can do. I need to find out whats causing the coolant to sludge though, I dont want to rebuild of replace the transmission until I figure that out :confused:
 
There still may have been some residue in the cooling system. No flush will get it all. Also, over time, corrosion occurs on the inside of the engine that will look kinda like a film. The water pump bearings start to wear and do the same thing.
 
did you clean the over flow tank and the hose to it, change the rad cap?

that sludge was most likely just dex sludge, the trans i bet is just a coincidence. if the trans fluid had just old tranny fluid in it, not coolant as well. and the level never dropped or raised on you.

dex sludge does stick inside good. i flushed my engine and rad, by taking out the t state, put the hose back on, then i pulled the lower hose off the water pump, drained the rad, then put that hose back on. then start the engine, put the garden hose in the rad, let it run till clear water comes out of the upper hose to the ground/bucket. put that hose back on, drive the car for a day or 2 with just water.

then dump it again, and top off with coolant.

my coolant is still green, but the rad cap does get some sludge on it still.
 


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