350z-Na

iTrader: (5)

Hey guys, I'm in the process of fully draining my coolant system, and I noticed that there is yellow sandy substance in my radiator. The water looked clean while draining it. I check my oil every week and the colour is normal like always.

What do you guys think it could be?

Sean

I need to see it, I think there are a couple things it could be. Corrosion, a dissolving seal in the coolant system, water-pump bearing, or the prior owner added a chemical to the coolant system that is now breaking down (like a Gumout or a leak stopper).

350z-Na

iTrader: (5)

Ok, i will post some pictures once i get home.

2004Black350z

iTrader: (37)

threads like this blow me away. Want help but dont have anything to help us

350z-Na

iTrader: (5)

I didn't think i would've need to post pics, since i pretty much described it. I will post pics once i get home from work. My bad though

350z-Na

iTrader: (5)

Sean

The picture is no help this time. drain the coolant through paper in a strainer. Once it dries, take a picture of that and let us know if it feels metalic.

jds4181t

is your vehicle auto

SR71

iTrader: (1)

Looks like two different kinds of coolant got mixed together that didn't work well with each other and it coagulated.

jds4181t

if its an auto, it looks like the trans cooling line is leaking into the radiator, seen that happen a lot on nissan..

350z-Na

iTrader: (5)

No, my car is 6mt

350z-Na

iTrader: (5)

I already drained the coolant from the radiator plug. I still have the coolant in the block. How do i drain it from the block? I just remove the lower hose?

350z-Na

iTrader: (5)

The colour of the coolant was green like usual.

jds4181t

i think an easy step would be to use a block tester

350z-Na

iTrader: (5)

Can't really test it, since i'm doing full engine bay wire tuck. I noticed as well my cylinder #6 has blown spark plug seal. I'm going to scoop up a bit of the substance and mix in a cup of water, and do what Sean suggested.

350z-Na

iTrader: (5)

Sean, what type of paper should I use?

Sean

Ideally you would use medical straining paper, but assuming you don't have that, use a 3m mask or a coffee filter.

350z-Na

iTrader: (5)

Alright, thx a lot. I will check it out tomorrow.

mr. sparco

iTrader: (13)

Silicate drop out, the coolants been in the system for too long and is "spent." Do a search on it, turns into yellow crust over time. Usually kills the water pump if left unchanged for too long.

zetosan

Hey man did you figure out what the yellow substances were? cause my thermostat gave up and i was changing and did a coolant flush and i also saw the yellow stuffs in the radiator through the cap. you think its anything to be worried about?