Rusty coolant (78 GMC k15 350ci)

[235SB]

So, I got this truck 6 months ago and it was running tap water for coolant. I swapped this out for a basic ‘b’ type coolant (this might be an Australia/NZ definition, basically means it contains only inhibitors for rust, corrosion & cavitation. No Anti-Freeze/Anti-Boil emulsions).

It’s always looked a bit murky but checking on it this morning i thought I’d blown a head gasket as it looked like milkshake down the radiator cap. I pulled the rad hose to get all the water out and it’s actually just brown and rusty, but no sign of oil. (I also drained some oil which looks fine, no evidence of water).

So… am I in the clear with regards to a heeadgasket issue? And if so, why is my radiator so effing dirty?! Do I just need a professional flush? Do I just fill ‘er up and stop worrying?

Any advice much appreciated.

 

[StickyLifter]

I'm not an expert by any means, but I think I would probably flush the system if it were mine. Hard to say what kind of coolant the previous owner had in it.

 

[Vbb199]

So, I got this truck 6 months ago and it was running tap water for coolant.....

.....why is my radiator so effing dirty?! Do I just need a professional flush? Do I just fill ‘er up and stop worrying?

Any advice much appreciated.

Tap water rusts everything internally usually, have them flush the whole system really really good

 

[235SB]

Thanks guys... flushing it is, then. Appreciate the reassurance.