Coolant Overflow Tank With Lots of Sediment in it

[yugoner]

2007 Fuso FG coolant reserve tank has a hell of a lot of sediment. Sand and grit on the bottom. White residue sticking to the inside walls on the fist 2 inches up the tank.
My coolant in the radiator is full, and clear looking good. Not milky at all, no sign of sediment.
Truck has sat for at least the last year before I purchased it.
I was wondering if my head gasket may be a bit funky. Yet I'm not overheating, or losing coolant, or gaining coolant levels at all.
I also noticed as a new buyer that my coolant system pressures up very fast when I start the vehicle. Within 3-5 minutes, and upon shutting vehicle down, I have to burp the rad cap to avoid coolant spilling everywhere. Wondering if this is normal for these truck platforms, or if I have some gas in the system because of this head gasket.
I'm just thinking the worst here but hoping its just simply sediment that's in their and isn't from fuel/oil mixing with coolant.
any words?

Thanks

 

[gait]

two related issues:-

1:- clean out the reservoir, if there's no evidence in the radiator its probably dried "stuff" from sitting idle. May need hot water.

2:- "burping" doesn't sound good. Look for telltale oil on surface of water in radiator. I would first try replacing the radiator cap - after a year of sitting the seal may not be sealing. Make sure the seat in radiator top is clean.

Only time I had an overflow of radiator water was when I drove too far in too high gear in too hot weather with rubbish fuel - water circulation not sufficient to remove heat at low revs under load.

 

[yugoner]

The burping is just me saying that there is pressure built up under cap within minutes of starting truck.
Seems interesting to me. Makes me think combustion gasses are getting into it, unless it's just the water pump.
Burping is my way of saying when I want to take radiator cap off after I start it briefly I have to go very gingerly about it and let antifreeze spill out from pressure.
I just drove 600km, didn't lose any oil, didn't lose/gain any antifreeze, and my thermostat stayed consultant the entire time.
Cleaned my resovoir coolant tank and haven't had any sign of deposit since. No signs of milky oil in engine, which can happen from coolant mixing with it.
I think I'm fine.
I'm just curious, from a cold start, does your system get slight pressure in radiator literally after 1 minute is idling??
Thanks gait!

 

[yugoner]

I'm interested as to how many fusos have had head gasket issues anyways..
I'm assuming not many

 

[unkamonkey]

The pressure should build as the engine warms up.
I have to wonder if a PO filled the overflow tank from a salts laden creek and that is where the deposits came from. I have had to replenish the radiator in my Volvo from a nasty cow tank out in the fields. Lots of flushing it out after that.
I have never had a head gasket issue from it. Cracked exhaust manifold and issues with the tire shop people not knowing which way to turn the lug nuts on older MFs and trying to over torque them.

 

[gait]

...
I'm just curious, from a cold start, does your system get slight pressure in radiator literally after 1 minute is idling??
Thanks gait!

not something I've noticed. But then I haven't checked.

Probably not a good test on my system, I have a webasto diesel heater in the circuit with a reservoir (and pressure cap) higher than the engine radiator.