Radiator funk? What is it?

I pulled my radiator cap off on this fine spring day and look what was underneath. Ewwwww.... It's fresh coolant as of last summer's timing belt change. It's consistency is that of fine dirt or clay. Anyone seen anything like this?

 

almost looks like excessive use of stop leak, but can't say for sure...does it run hot?

 

No. Not running hot. Never had stop leak in it, whatever that is. As part of the timing belt replacement, i had to pull the radiator off, drain it, and then reverse the process later. I used Zerex. Is it possible that a new batch of antifreeze could have flushed some grime out this winter? It was all collected at the radiator cap, deposited slowly. So...let's say it's simple dirt. How did it get there?

 

Hopefully it's just a bad radiator cap.

 

Well it certainly took a long time to show up, but that looks to be casting sand from inside the block.

 

I agree ^

 

Looks like sand to me too.

 

That's a BIZARRE thesis. Casting sand??

So now what? Is there a coolant filter in the 3.4 5VZ-FE?

 

I well could be wrong but the looks kind of like what I thought of as "hard water deposits". I get a little each time I change the coolant. But it may just be a little dirt/corrosion coming out or casting sand as others have said. I definitely would use a cooling system flush product. Refill with premixed 50/50 coolant or use distilled water with the anti-freeze. Maybe a new radiator cap too. \/\/ As long as there isn't any oil showing up or bubbles I wouldn't sweat it, just change and roll on. And no filter I am aware of. I am not a mechanic though, I just try to keep my own stuff running.

 

There's no filter/screen for Toyota coolant systems. You can flush it a couple times, or do a plain drain/refill a couple times; if using water (without coolant) for flushing, do NOT drive the vehicle, idle only and monitor temp gauge carefully. You don't want to run the engine for an extended period of time, only long enough to cycle the thermostat through a time or two. Refill with fresh coolant/water mix and let it ride.

The tolerances on the water pump and thermostat are large enough that it won't harm either of them and it doesn't appear to be enough sand to stop up the heat exchange tubes. If the heat exchange tubes were plugged, you'd have MUCH worse problems with the coolant system and you'd have seen indicators much earlier than this.

End result, if it's casting sand, it's a bit of a fluke and may not occur again. I wouldn't be overly concerned about it.

 

Could this be from mixing 'green' coolant with 'red' coolant by mistake? Not sure what happens when you mix them up.

 

Mixing the two can shake crap loose and produce gunk on the cap. Found that out first hand on another rig.

Green for old systems that came with green, Red Dexcool? for newer.

A quick hot overheat can pop sand particles loose, when bubbles form and burst on the inner surfaces. But that's smoking hot to do that.

That stuff looks to be smeared on the wet side rubber baffle where it contacts the neck, almost looks like wax mixed with fine river dirt.

A full flush with heater core flowing, thermostat open, ect. Maybe two depending on what the first looks like after a few hundred miles. With that much accum, I would do two regardless after 1000 miles or under. The inside of the radiator neck looks coated waay down in there from the pic. Check the overflow and make sure all of that system is clean and clear, That cap is loaded up. Toothbrush/flush that out and maybe run down to the parts store and have them pressure test that. If anything the test will force the river dirt? out the vent and then it should be clear.