My dealer installed a new radiator in my Lazer 27HP LC last fall before putting the mower away for the winter. It had been leaking since new and after 2 years it was decided that a new radiator was needed. This spring upon using the mower for about 10 minutes the mower overheated and blew most of the antifreeze out the radiator cap. Took it back to the dealer and they refilled it and let it run for a long time and nothing happened. They ordered a new cap for it but said it would probably be OK. Although they did run the mower it wasn't under a full load and not mowing. I picked it up today, used it for 10 minutes or so and noticed the gauge read hot. On my way to the trailer the antifreeze let loose as it was once again all over the place. I dropped it off once again at the dealer. Any thoughts as to what is making this overheat?