I have a Mitsubishi tractor D2000 with a 2cyl. 2DR5 Diesel engine. I recently bought this tractor and it almost immediately started squirting radiator fluid from the overflow tube on the radiator. I had a new core put in radiator because old one started leaking when it was being tested. I put a new thermostat in it which it did not have one when I took it out to check. I put a new belt on when I had radiator out. Put back together and still have problem. Tractor will really flow fluid sometimes. I can release pressure off of cap and then run it for a little while without it doing. No white smoke tractor engine seems to run fine. No water in oil or coming from exhaust. Can someone tell me what may be wrong with tractor.