coolant headgasket material or just dirt?

[proveitwithdata]

Nissan Im working on in another thread, came with factory green then replaced with Prestone universal green. Recently thermostat failed (170F is opening temp), didnt completely overheat, but pushed into the 215s from what I was told. Mechanic also replaced the radiator, and did a complete fill with Prestone Universal.

I was checking fluids today, and the radiator is full, but it has some black particles suspended in the rad. The overflow when shining light through the tank, has an interesting pattern. Clear up top, then the bottom has a light golden color. Looking at it from the top into the tank, its green.

I'm thinking HG failure, but waiting on the combustion gas test kit to confirm. Vehicle doesnt smoke.

Am I out of line for thinking a slow but steady HG failure?

 

[zrxkawboy]

I'm not sure, but it doesn't hurt to check with the test kit...peace of mind, if nothing else.

 

[Lubener]

I doubt it is head gasket material. Coolant would under pressure would cause coolant to be pushed out and likely overflow the coolant bottle. I think you have some debris which developed over time or was introduced when the cooling system was serviced. 215 degrees is not going to blow the head gasket.