the 'waterfall' sound from behind the dash is classic to BHG in these cars. its some air that has gotten in the lines. its not necessarily BHG but it could easily be. its not common but its possible to have a leak that sucks air in...
signs to look for:
-white exhaust. most cars start with this until warmed up but with BHG it keeps going. its coolant getting in the cylinders and getting burned.
-'milkshake' like sludge under the oil cap. this is coolant getting into your oil and causing a sludge as it mixes. btw this is VERY bad for your bearings.
-loss of coolant (self explanatory)
-overheating. beware of this, it WILL warp your head! in more extreme cases it can crack the head making it scrap
-bubbling in the coolant overflow tank. this is exhaust gasses entering the coolant system creating the bubbling/overflowing
now you also mentioned the 'rusty coolant'. that sounds like badly contaminated coolant. check that out. the antifreeze serves two purposes for the engine - 1. prevents freezing in cold weather and 2. stops galvanic corrosion between the aluminum head and the cast iron block. this is why coolant has to be flushed every now and then. after a while it loses the ability to stop the galvanic corrosion and it begins to rot out the block and head.
the next question is how much do you feel comfortable doing yourself? a simple compression test can tell you a lot here. theres enough information around to get the job done if you can take the time to learn it.
signs to look for:
-white exhaust. most cars start with this until warmed up but with BHG it keeps going. its coolant getting in the cylinders and getting burned.
-'milkshake' like sludge under the oil cap. this is coolant getting into your oil and causing a sludge as it mixes. btw this is VERY bad for your bearings.
-loss of coolant (self explanatory)
-overheating. beware of this, it WILL warp your head! in more extreme cases it can crack the head making it scrap
-bubbling in the coolant overflow tank. this is exhaust gasses entering the coolant system creating the bubbling/overflowing
now you also mentioned the 'rusty coolant'. that sounds like badly contaminated coolant. check that out. the antifreeze serves two purposes for the engine - 1. prevents freezing in cold weather and 2. stops galvanic corrosion between the aluminum head and the cast iron block. this is why coolant has to be flushed every now and then. after a while it loses the ability to stop the galvanic corrosion and it begins to rot out the block and head.
the next question is how much do you feel comfortable doing yourself? a simple compression test can tell you a lot here. theres enough information around to get the job done if you can take the time to learn it.