Hi how are you? I flushed my radiator out and put valvoline
coolant in due to having really dirty water in it (just bought
recently) and I haven't had a problem, but after I drove for a
while a bit of sludge would come to the top so I have
drained and filled with more expensive coolant and since I
have done that it overheats and chugs/splutters at low
speed/idle, so I replaced the thermostat and put more of
the expensive coolant in and it still overheating and running
So in short, since I've put the dearer coolant in I've had
nothing but problems, but with the cheaper coolant it was
fine. The dearer ones contain ethylene glycol and the
cheaper one doesn't, would that matter????
Thanks for your time
I'd appreciate any feedback thank you
when filling a coolant system it must be permitted to recede while filling ( purge). this means don't just fill it and cap it but rather wait for it to recede and add more. You will have to wait a few times while filling the system. Think of it as air in the system that should be given time to escape while filling. Check the oil for milky color ( dip stick and under the oil cap)as well the sludge could be oil mixing with the coolant ( blown head gasket ) see if you have smoke coming out the tail pipe while running as well.