Hello, I have a rotax max with rust in its cooling system, inside the radiator and engine cooling ports, albeit it doesnt look completely rusted rather a bit patchy, but water comes out brown and sludgy, so Im trying to find a way to remove the rust, I tried 4 different flushing solutions, (pour in solution, run kart until 55C, drain, pour in distilled, run, drain) which havent had an effect on it, would I need some kind of rebuild for the engine and a new radiator? Or is there a cheaper way?
The water comes out brown and sludgy after leaving it for how long?
If I’m not driving for a ~month, I drain the radiator. It comes out clear. If you leave it for 6 months I’d expect it to be brown from rust.
I keep the radiator drained in storage, brown water and sludge only presents itself when i run it on the track, leaving the water in doesnt change it brown or into sludge for some reason
It’s probably the bolts holding down the combustion chamber. If you aren’t racing you can break the seal and simply remove the red cover (evo engines) to get to the bolts. Replace them with stainless. If you are racing in a series then an engine builder will need to do it for you and reseal.
Without replacing those it will continue to add rust to the water if they are really bad.
Wouldnt it just be coming from the inside of the cooling system? Because the top port is cleary rusty, not saying that the bolts arent the issue, just that it might be coming from a bigger issue.