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Mustard like substance in radiator

3K views 11 replies 5 participants last post by  behind-bars 
#1 ·
I was doing some battery maintaince on my 93 today, Popped the radiator cap off and see a mustard like substance. It was on the bottom of the radiator cap and i could see it caked up all along the filler neck and in between the coils inside the radiator. Its soft and mushy.

I am not sure what the cause of it was though, A few weeks back I used white vinegar to flush the cooling system out, then ran water through several times and drained it all, then refilled with the standard water/coolant and added the bars leak power.


I think it may just be the bars leak, but why would it turn yellowish/green and stick to the filler neck? I pulled the drain at the bottom of the radiator and it came out fresh looking coolant so I know its not entirely clogged up.

Anyone seen this before? perhaps left over vinegar caused some type of reaction?
 
#4 ·
Oil and ATF dipsticks look normal. I took a few pics of the radiator before the cleaning began, I really didnt want to reflush it since i just did it a few weeks back, but once I saw how much of it their was all throughout the system, and how the thermostat housing was clogged up I knew their was no alternative.

I had to blow it out of the heater core aswell.

Off to the pics... This is still after i cleaned some of it yesterday. I am glad it didnt mix with oil, and Atf. But does it look like scale?

 
#7 ·
Yeah, Thats off tap water, Our local tap is actually pretty good though. Apparently not good enough lol. Ill probably continue the massive flushing via tap, but then fill with distilled.

I read a neat trick from another site, they suggested using sock, or similar,as a filter. I may use a coffee filter at the end of the upper hose before it goes into the T-Stat to catch the gunk and help keep me from just recirculating it.
 
#9 ·
I think it was a combination of bars leak and scale. I really flushed it good today an will do so again tomorrow, I took the cap off the radiator and filled straight water and ran the car with cap off. After 2 secs i could see the yellow rising up to the top so i kept a trickle of fresh water going into the rad so the yellow would overflow out. I didn this for several mins then drained everything out totally, removed the T-Stat for more flow and repeated several times. Each time I took a hose off I could see the yellow running out of it. I flushed all hoses, Heater core etc and got it to run clear.

I peeked into the radiator from the fill neck and its nice and shiny lol :D

So vinegar is a great cleaner, but its reallly important to get it ALL out before adding fresh antifreeze lol
 
#12 ·
Yeah, I just kept flushing over and over. If its as bad as mine I had good luck leaving the rad cap off, as the engine ran the scale floated up to the fill neck and i ran a stream of water in as it foamed at the top, the yellow spilled over the top and out of the radiator, Of course my lower engine bay is all yellow now, but who cares lol
 
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