Re: My JD 332
As coolant, or whatever is in the radiator, heats up, it expands creating pressure in the radiator. when the pressure in the radiator meets or exceeds the rating of the radiator cap, (yours is probably 15psi) the valve on the bottom of the cap opens and allows excess pressure to bleed off. This is a "normal" condition..assuming the cap is not worn and relieving pressure to soon (like 5 or 10 psi).
Soo, where does that leave you...no place yet! After running for only an hour...or even 3 or 4 hours...the flush hasn't done too much. This is a chemical reaction that has to dissolve the corrosion and chemical deposits left from your antifreeze breaking down. It usually takes a few hours, (6-8) AT OPERATING TEMPERATURE, to do this...the clock doesn't start when you turn the key! And one more quick comment. When your engine is running, your fan is cooling the radiator. When you stop the engine, especially after working it hard, the heat in the engine transfers into the coolant making it hotter and possibly "boiling over".
Let the engine cool, remove cap, and check level. You want to see the level maybe 1/2 inch or slightly more below the bottom of the radiator neck. As far as the overflow tube, pull it off and blow air through it. If you can get air through, it'll be fine. Run the flush for the time on the bottle and even a few more hours. Cool, drain, fill with water (rinse), and run for another hour. You need to get to operating temp so your thermostat opens and "rinses" both the radiator and the engine. With just water, I'd try mowing and see what happens...maybe a light, maybe not.
I've been following a post on a forum...maybe this site, maybe another... about a 332 overheating. The guy is just starting to troubleshoot but another poster commented that he had a new water pump, thermostat, radiator rodded, and STILL had overheating problems. His closing comment was that the system wasn't designed correctly. I don't buy it! I'm thinking more like a shabby rodding job and he still has a bad radiator.
Mow for a bit with plain water and keep us posted! Bob