August 2023:
Well, I overheated my car on the track and now I discovered my thermostat cap is cracked. The cap is made of cast aluminum and the crack seems to reach the fan sensor’s threads. This may have been slowly leaking for a long time as the grime built underneath it on top of the transmission seem to make sense now. I must have just made it worse after overheating it and taking it off and putting it back on.
This part (17561-61F00-000) is discontinued from Suzuki. I am currently having it worked on at a local shop and they will produce it with billet stock. Waiting for the first sample to be made to test fit.