What would cause a wax like residue to coat the entire coolant system, reservoir, radiator, engine, etc? I've got a black waxy residue that will not flush out.
Another interesting characteristic is that the solidified residue liquifies when heated and floats to the top like oil. But goes solid again when cooled.
A significant factor: 200k miles, coolant probably never been flushed, aged Dexcool here in a 2006 Chevy 5.3l suburban.
I've identified these possibilities:
The problem with the head gasket theory is that compression, leak down and block tests all pass! No signs of combustion gasses getting into coolant. That said, I can't rule this out completely... perhaps it's a small leak that only happen under load?
I've never thought of oil becoming wax, but then again, I also don't understand Dexcool chemistry. But then I learned that overheated oil actually does solidify, also known as engine sludge that can build up in the case due to being burnt. But never heard of this building up in the coolant! Unless perhaps it's literally burnt and accumulating slowly over a long period of time through an undetectable head leak, now completely overtaking the coolant system.
Anyway, I'm frustrated. Even if my head gasket is fine, the engine is doomed as there is no way to get this crap out. Not even a radiator specialty shop offers a heated flush, which is is the only way this junk will ever have a possibility of leaving the system!
Anyone else ever seen anything like this? Ideas ?
Another interesting characteristic is that the solidified residue liquifies when heated and floats to the top like oil. But goes solid again when cooled.
A significant factor: 200k miles, coolant probably never been flushed, aged Dexcool here in a 2006 Chevy 5.3l suburban.
I've identified these possibilities:
- Burnt oil (head gasket leak)
- Dexcool mixed with air and/or other contaminant
- Dexcool eating at gaskets and seals
The problem with the head gasket theory is that compression, leak down and block tests all pass! No signs of combustion gasses getting into coolant. That said, I can't rule this out completely... perhaps it's a small leak that only happen under load?
I've never thought of oil becoming wax, but then again, I also don't understand Dexcool chemistry. But then I learned that overheated oil actually does solidify, also known as engine sludge that can build up in the case due to being burnt. But never heard of this building up in the coolant! Unless perhaps it's literally burnt and accumulating slowly over a long period of time through an undetectable head leak, now completely overtaking the coolant system.
Anyway, I'm frustrated. Even if my head gasket is fine, the engine is doomed as there is no way to get this crap out. Not even a radiator specialty shop offers a heated flush, which is is the only way this junk will ever have a possibility of leaving the system!
Anyone else ever seen anything like this? Ideas ?